linuxcnc EMC2 Users Manual

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Integrators Manual V2.4

The EMC Team

December 9, 2011

Page 2

EMC V2.4 Integrator Manual

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EMC Handbook is the product of several authors writing for linuxCNC.org. As you ﬁnd it to be of

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Page 3

Contents

Cover I

1 Important Concepts 1

1.1 Stepper Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.1.1 Base Period . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.1.2 Step Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.2 Servos . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1.2.1 Tuning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1.2.2 Proportional term . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1.2.3 Integral term . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1.2.4 Derivative term . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

1.2.5 Loop tuning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

1.2.6 Manual tuning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

1.3 RTAI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

I Conﬁguration 4

2 Hardware 5

2.1 Latency Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

2.2 Port Address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

3 Conﬁg Files 8

3.1 Files Used for Conﬁguration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

4 INI File 9

4.1 The INI File Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

4.1.1 Comments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

4.1.2 Sections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

4.1.3 Variables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

4.1.4 Deﬁnitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

4.2 Sections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

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EMC V2.4 Integrator Manual CONTENTS

4.2.1 [EMC] Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

4.2.2 [DISPLAY] Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

4.2.3 [FILTER] Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

4.2.4 [RS274NGC] Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

4.2.5 [EMCMOT] Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

4.2.6 [TASK] Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

4.2.7 [HAL] section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

4.2.8 [TRAJ] Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

4.2.9 [AXIS_<num>] Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

4.2.9.1 Homing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

4.2.9.2 Servo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

4.2.9.3 Stepper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

4.2.10[EMCIO] Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

4.3 Homing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

4.3.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

4.3.2 Homing Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

4.3.3 Conﬁguration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

4.3.3.1 HOME_SEARCH_VEL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

4.3.3.2 HOME_LATCH_VEL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

4.3.3.3 HOME_FINAL_VEL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

4.3.3.4 HOME_IGNORE_LIMITS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

4.3.3.5 HOME_USE_INDEX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

4.3.3.6 HOME_OFFSET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

4.3.3.7 HOME . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

4.3.3.8 HOME_IS_SHARED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

4.3.3.9 HOME_SEQUENCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

4.4 Lathe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

4.4.1 Default Plane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

4.4.2 INI Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

5 EMC2 and HAL 27

5.1 motion (realtime) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

5.1.1 Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

5.1.2 Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

5.1.3 Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

5.1.4 Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

5.2 axis.N (realtime) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

5.2.1 Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

5.2.2 Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

5.3 iocontrol (userspace) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

5.3.1 Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

III

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II HAL 32

6 Getting Started 33

6.1 Hal Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

6.1.1 loadrt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

6.1.2 addf . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

6.1.3 loadusr . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

6.1.4 net . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

6.1.5 setp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

6.1.6 unlinkp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

6.1.7 Obsolete Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

6.1.7.1 linksp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

6.1.7.2 linkps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

6.1.7.3 newsig . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

6.2 Hal Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

6.2.1 Bit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

6.2.2 Float . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

6.2.3 s32 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

6.2.4 u32 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

6.3 Hal Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

6.4 HAL Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

6.5 Logic Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

6.5.1 and2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

6.5.2 not . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

6.5.3 or2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

6.5.4 xor2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

6.5.5 Logic Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

6.6 Conversion Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

6.6.1 weighted_sum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

6.7 Halshow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

6.7.1 Starting Halshow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

6.7.2 Hal Tree Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

6.7.3 Hal Show Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

6.7.4 Hal Watch Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

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7 Basic Conﬁguration 48

7.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

7.2 Maximum step rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

7.3 Pinout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

7.3.1 standard_pinout.hal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

7.3.2 Overview of the standard_pinout.hal . . . . . . . . . . . . . . . . . . . . . . . . . . 50

7.3.3 Changing the standard_pinout.hal . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

7.3.4 Changing the polarity of a signal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

7.3.5 Adding PWM Spindle Speed Control . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

7.3.6 Adding an enable signal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

7.3.7 Adding an external ESTOP button . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

8 HAL Components 53

8.1 Commands and Userspace Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

8.2 Realtime Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

8.2.1 abs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

8.2.2 and2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

8.2.3 at_pid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

8.2.4 axis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

8.2.5 biquad . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

8.2.6 bldc_hall3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

8.2.7 blend . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

8.2.8 charge_pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

8.2.9 clarke2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

8.2.10clarke3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

8.2.11clarkeinv . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

8.2.12classicladder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

8.2.13comp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

8.2.14constant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

8.2.15conv_bit_s32 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

8.2.16conv_bit_u32 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

8.2.17conv_ﬂoat_s32 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

8.2.18conv_ﬂoat_u32 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

8.2.19conv_s32_bit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

8.2.20conv_s32_ﬂoat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

8.2.21conv_s32_u32 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

8.2.22conv_u32_bit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

8.2.23conv_u32_ﬂoat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

8.2.24conv_u32_s32 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

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8.2.25counter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

8.2.26ddt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

8.2.27deadzone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

8.2.28debounce . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

8.2.29edge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

8.2.30encoder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

8.2.31encoder_ratio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

8.2.32estop_latch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

8.2.33feedcomp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

8.2.34ﬂipﬂop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

8.2.35freqgen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

8.2.36gantrykins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

8.2.37gearchange . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

8.2.38genhexkins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

8.2.39genserkins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

8.2.40hm2_7i43 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

8.2.41hm2_pci . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

8.2.42hostmot2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

8.2.43hypot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

8.2.44ilowpass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

8.2.45integ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

8.2.46invert . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

8.2.47joyhandle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

8.2.48kins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

8.2.49knob2ﬂoat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

8.2.50limit1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

8.2.51limit2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

8.2.52limit3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

8.2.53logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

8.2.54lowpass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

8.2.55lut5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

8.2.56maj3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

8.2.57match8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

8.2.58maxkins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

8.2.59minmax . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

8.2.60motion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

8.2.61mult2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

8.2.62mux2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

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8.2.63mux4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

8.2.64mux8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

8.2.65near . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

8.2.66not . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

8.2.67offset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

8.2.68oneshot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

8.2.69or2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

8.2.70pid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

8.2.71pluto_servo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

8.2.72pluto_step . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

8.2.73pwmgen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

8.2.74rotatekins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

8.2.75sample_hold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

8.2.76sampler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

8.2.77scale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

8.2.78scarakins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

8.2.79select8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

8.2.80serport . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

8.2.81siggen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

8.2.82sim_encoder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

8.2.83sphereprobe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

8.2.84stepgen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

8.2.85steptest . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

8.2.86streamer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

8.2.87sum2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

8.2.88supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

8.2.89thc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

8.2.90threads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

8.2.91threadtest . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

8.2.92timedelay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

8.2.93timedelta . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

8.2.94toggle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

8.2.95toggle2nist . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

8.2.96tripodkins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

8.2.97tristate_bit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

8.2.98tristate_ﬂoat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

8.2.99trivkins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

8.2.100updown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

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8.2.101wcomp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

8.2.102weighted_sum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

8.2.103xor2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

8.3 Hal Meter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

8.4 Stepgen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

8.4.1 Installing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

8.4.2 Removing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

8.4.3 Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

8.4.4 Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

8.4.5 Step Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

8.4.6 Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

8.5 PWMgen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76

8.5.1 Installing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76

8.5.2 Removing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76

8.5.3 Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76

8.5.4 Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

8.5.5 Output Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

8.5.6 Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

8.6 Encoder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

8.6.1 Installing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

8.6.2 Removing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

8.6.3 Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

8.6.4 Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

8.6.5 Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

8.7 PID . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

8.7.1 Installing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

8.7.2 Removing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

8.7.3 Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

8.7.4 Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83

8.7.5 Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83

8.8 Simulated Encoder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

8.8.1 Installing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

8.8.2 Removing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

8.8.3 Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

8.8.4 Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

8.8.5 Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

8.9 Debounce . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

8.9.1 Installing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

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8.9.2 Removing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

8.9.3 Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

8.9.4 Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

8.9.5 Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

8.10Siggen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

8.10.1Installing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

8.10.2Removing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

8.10.3Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

8.10.4Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

8.10.5Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

9 Parallel Port 87

9.1 Parport . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

9.1.1 Installing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

9.1.2 Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

9.1.3 Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

9.1.4 Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90

9.1.5 Common problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90

9.1.6 Using DoubleStep . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90

9.2 probe_parport . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

9.2.1 Installing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

10 Hal User Interface 92

10.1Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

10.2Halui pin reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

10.2.1Abort . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

10.2.2Axis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

10.2.3E-Stop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

10.2.4Feed Override . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

10.2.5Flood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

10.2.6Homing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

10.2.7Jog . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

10.2.8Joint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

10.2.9Lube . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

10.2.10Machine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

10.2.11Max Velocity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

10.2.12MDI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

10.2.13Mist . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

10.2.14Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

10.2.15Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

10.2.16Spindle Override . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

10.2.17Spindle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

10.2.18Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

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11 HAL Examples 98

11.1Manual Toolchange . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98

11.2Compute Velocity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98

11.3Soft Start . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101

12 Virtual Control Panel 103

12.1Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

12.2Panel Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104

12.3Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105

12.4AXIS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105

12.5Stand Alone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106

12.6Widgets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

12.6.1Label . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

12.6.2LEDs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

12.6.2.1Round LED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

12.6.2.2Rectangle LED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110

12.6.3Buttons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110

12.6.3.1Text Button . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110

12.6.3.2Checkbutton . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111

12.6.3.3Radiobutton . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111

12.6.4Number Displays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112

12.6.4.1Number . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112

12.6.4.2s32 Number . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112

12.6.4.3u32 Number . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113

12.6.4.4Bar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113

12.6.4.5Meter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113

12.6.5Number Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114

12.6.5.1Spinbox . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114

12.6.5.2Scale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114

12.6.5.3Dial . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115

12.6.5.4Jogwheel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116

12.6.6Images . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116

12.6.6.1Image Bit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117

12.6.6.2Image u32 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117

12.6.7Containers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117

12.6.7.1Borders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118

12.6.7.2Hbox . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118

12.6.7.3Vbox . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119

12.6.7.4Labelframe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119

12.6.7.5Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120

12.6.7.6Tabs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120

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13 VCP Examples 122

13.1AXIS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122

13.2Floating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122

13.3Jog Buttons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123

13.4Port Tester . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127

13.5GS2 RPM Meter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131

III Hardware Drivers 134

14 AX5214H 135

14.1Installing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135

14.2Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135

14.3Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136

14.4Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136

15 GS2 VFD 137

16 Mesa HostMot2 139

16.1Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139

16.2Firmware Binaries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139

16.3Installing Firmware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140

16.4Loading HostMot2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140

16.5Watchdog . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140

16.6HostMot2 Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141

16.7Pinouts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141

16.8PIN Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142

16.9Firmware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142

16.10HAL Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142

16.11Conﬁgurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143

16.12GPIO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144

16.13StepGen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145

16.14PWMGen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146

16.15Encoder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147

16.16Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149

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17.1Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150

17.2Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151

17.3Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151

17.4Connector pinout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152

17.4.1Connector P2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152

17.4.2Connector P3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152

17.4.3Connector P4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153

17.4.4LEDs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154

18 Motenc 155

18.1Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155

18.2Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156

18.3Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156

19 OPTO22 PCI 157

19.1The Adapter Card . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157

19.2The Driver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157

19.3PINS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157

19.4PARAMETERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158

19.5FUNCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158

19.6Conﬁguring I/O Ports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158

19.7Pin Numbering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159

20 Pico PPMC 160

20.0.1Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160

20.0.2Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161

20.0.3Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162

21 Pluto-P 163

21.1General Info . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163

21.1.1Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163

21.1.2Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163

21.1.3Physical Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163

21.1.4LED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164

21.1.5Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164

21.1.6PC interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164

21.1.7Rebuilding the FPGA ﬁrmware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164

21.1.8For more information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164

21.2pluto-servo: Hardware PWM and quadrature counting . . . . . . . . . . . . . . . . . . . . 165

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21.2.1Pinout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165

21.2.2Input latching and output updating . . . . . . . . . . . . . . . . . . . . . . . . . . . 166

21.2.3HAL Functions, Pins and Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . 167

21.2.4Compatible driver hardware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167

21.3Pluto-step: 300kHz Hardware Step Generator . . . . . . . . . . . . . . . . . . . . . . . . . 167

21.3.1Pinout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167

21.3.2Input latching and output updating . . . . . . . . . . . . . . . . . . . . . . . . . . . 168

21.3.3Step Waveform Timings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168

21.3.4HAL Functions, Pins and Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . 169

22 Servo-To-Go 170

22.0.5Installing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170

22.1Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170

22.2Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171

22.2.1Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171

IV Advanced topics 172

23 Kinematics in EMC2 173

23.1Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173

23.1.1Joints vs. Axes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173

23.2Trivial Kinematics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173

23.3Non-trivial kinematics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174

23.3.1Forward transformation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174

23.3.2Inverse transformation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176

23.4Implementation details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176

V Tuning 177

24 Stepper Tuning 178

24.1Getting the most out of Software Stepping . . . . . . . . . . . . . . . . . . . . . . . . . . . 178

24.1.1Run a Latency Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178

24.1.2Figure out what your drives expect . . . . . . . . . . . . . . . . . . . . . . . . . . . 179

24.1.3Choose your BASE_PERIOD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180

24.1.4Use steplen, stepspace, dirsetup, and/or dirhold . . . . . . . . . . . . . . . . . . . 181

24.1.5No Guessing! . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181

25 PID Tuning 183

25.1PID Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183

25.1.1Control loop basics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183

25.1.2Theory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184

25.1.3Loop Tuning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184

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VI Ladder Logic 186

26 Ladder programming 187

26.1Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187

26.2Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187

27 Classic Ladder 189

27.1Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189

27.2Ladder Concepts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189

27.3Languages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190

27.4Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190

27.4.1Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190

27.4.2Realtime Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190

27.4.3Variables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190

27.5Loading the Classic Ladder user module . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191

27.6Classic Ladder GUI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192

27.6.1Sections Manager . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192

27.6.2Section Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192

27.6.3The Variable Windows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193

27.6.4Symbol Window . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196

27.6.5The Editor window . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197

27.6.6Conﬁg Window . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198

27.7Ladder objects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199

27.7.1CONTACTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199

27.7.2IEC TIMERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200

27.7.3TIMERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201

27.7.4MONOSTABLES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201

27.7.5COUNTERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201

27.7.6COMPARE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202

27.7.7VARIABLE ASSIGNMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202

27.7.8COILS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203

27.7.8.1JUMP COIL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204

27.7.8.2CALL COIL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204

27.8Classic Ladder Variables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204

27.9GRAFCET Programming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206

27.10Modbus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207

27.10.1MODBUS Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209

27.10.2MODBUS Info . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210

27.10.3Communication Errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210

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27.10.4MODBUS Bugs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210

27.11Setting up Classic Ladder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211

27.11.1Add the Modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211

27.11.2Adding Ladder Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211

27.12Ladder Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 216

27.12.1Wrapping Counter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 216

27.12.2Reject Extra Pulses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 216

27.12.3External E-Stop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 217

27.12.4Timer/Operate Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220

27.12.5Tool Turret . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 221

27.12.6Sequential Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 221

VII Hardware Examples 222

28 Second Parallel Port 223

29 Spindle Control 224

29.10-10v Spindle Speed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224

29.2PWM Spindle Speed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224

29.3Spindle Enable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224

29.4Spindle Direction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225

29.5Spindle Soft Start . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225

30 Spindle Feedback 226

30.1Spindle Synchronized Motion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226

30.2Spindle At Speed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226

31 MPG Pendant 228

32 GS2 Spindle 230

VIII Diagnostics 231

33 Steppers 232

33.1Common Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232

33.1.1Stepper Moves One Step . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232

33.1.2No Steppers Move . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232

33.1.3Distance Not Correct . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232

33.2Error Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232

33.2.1Following Error . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232

33.2.2RTAPI Error . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 233

33.3Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 233

33.3.1Step Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 233

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EMC V2.4 Integrator Manual CONTENTS

IX FAQ 235

34 Linux FAQ 236

34.1Automatic Login . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 236

34.2Automatic Startup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 236

34.3Man Pages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 236

34.4List Modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237

34.5Editing a Root File . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237

34.5.1The Command Line Way . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237

34.5.2The GUI Way . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237

34.5.3Root Access . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237

34.6Terminal Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237

34.6.1Working Directory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237

34.6.2Changing Directories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238

34.6.3Listing ﬁles in a directory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238

34.6.4Finding a File . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238

34.6.5Searching for Text . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239

34.6.6Bootup Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239

34.7Convenience Items . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239

34.7.1Terminal Launcher . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239

34.8Hardware Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239

34.8.1Hardware Info . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239

34.8.2Monitor Resolution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239

X Appendices 240

35 Glossary 241

36 Legal Section 245

36.1Copyright Terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 245

36.2GNU Free Documentation License . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 245

XVI

Page 18

Chapter 1

Important Concepts

1.1 Stepper Systems

1.1.1 Base Period

BASE_PERIOD is the "heartbeat" of your EMC computer. Every period, the software step generator decides if it is time for another step pulse. A shorter period will allow you to generate more pulses per second, within limits. But if you go too short, your computer will spend so much time generating step pulses that everything else will slow to a crawl, or maybe even lock up. Latency and stepper drive requirements affect the shortest period you can use.

Worst case latencies might only happen a few times a minute, and the odds of bad latency happening just as the motor is changing direction are low. So you can get very rare errors that ruin a part every once in a while and are impossible to troubleshoot.

The simplest way to avoid this problem is to choose a BASE_PERIOD that is the sum of the longest timing requirement of your drive, and the worst case latency of your computer. This is not always the best choice for example if you are running a drive with a 20uS hold time requirement, and your latency test said you have a maximum latency of 11uS, then if you set the BASE_PERIOD to 20+11 = 31uS and a not-so-nice 16,129 steps per second.

The problem is with the 20uS hold time requirement. That plus the 11uS latency is what forces us to use a slow 31uS period. But the EMC2 software step generator has some parameters that let you increase the various time from one period to several. For example, if steplen is changed from 1 to 2, then it there will be two periods between the beginning and end of the step pulse. Likewise, if dirhold is changed from 1 to 3, there will be at least three periods between the step pulse and a change of the direction pin.

If we can use dirhold to meet the 20uS hold time requirement, then the next longest time is the

4.5uS high time. Add the 11uS latency to the 4.5uS high time, and you get a minimum period of

15.5uS. When you try 15.5uS, you ﬁnd that the computer is sluggish, so you settle on 16uS. If we leave dirhold at 1 (the default), then the minimum time between step and direction is the 16uS period minus the 11uS latency = 5uS, which is not enough. We need another 15uS. Since the period is 16uS, we need one more period. So we change dirhold from 1 to 2. Now the minimum time from the end of the step pulse to the changing direction pin is 5+16=21uS, and we don’t have to worry about the drive stepping the wrong direction because of latency.

For more information on stepgen see Section (8.4).

1.1.2 Step Timing

Step Timing and Step Space on some drives are different. In this case the Step point becomes important. If the drive steps on the falling edge then the output pin should be inverted.

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EMC V2.4 Integrator Manual Chapter 1. Important Concepts

1.2 Servos

1.2.1 Tuning

Servo systems must be "tuned" as they don’t quite work out of the box like a stepper system might. This is because servos don’t "step" in ﬁxed increments like steppers do. PID is the "Black Magic" that makes your servos move where you want them to move and when you want them to move.

PID stand for Proportional, Integral, and Derivative. The Proportional value determines the reaction to the current error, the Integral value determines the reaction based on the sum of recent errors, and the Derivative value determines the reaction based on the rate at which the error has been changing. They are three common mathematical techniques that are applied to the task of getting a working process to follow a set point. In the case of EMC the process we want to control is actual axis position and the set point is the commanded axis position.

Figure 1.1: PID Loop

By "tuning" the three constants in the PID controller algorithm, the controller can provide control action designed for speciﬁc process requirements. The response of the controller can be described in terms of the responsiveness of the controller to an error, the degree to which the controller overshoots the set point and the degree of system oscillation.

1.2.2 Proportional term

The proportional term (sometimes called gain) makes a change to the output that is proportional to the current error value. A high proportional gain results in a large change in the output for a given change in the error. If the proportional gain is too high, the system can become unstable. In contrast, a small gain results in a small output response to a large input error. If the proportional gain is too low, the control action may be too small when responding to system disturbances.

In the absence of disturbances, pure proportional control will not settle at its target value, but will retain a steady state error that is a function of the proportional gain and the process gain. Despite the steady-state offset, both tuning theory and industrial practice indicate that it is the proportional term that should contribute the bulk of the output change.

1.2.3 Integral term

The contribution from the integral term (sometimes called reset) is proportional to both the magnitude of the error and the duration of the error. Summing the instantaneous error over time (integrating the error) gives the accumulated offset that should have been corrected previously. The accumulated error is then multiplied by the integral gain and added to the controller output.

The integral term (when added to the proportional term) accelerates the movement of the process towards set point and eliminates the residual steady-state error that occurs with a proportional

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EMC V2.4 Integrator Manual Chapter 1. Important Concepts

only controller. However, since the integral term is responding to accumulated errors from the past, it can cause the present value to overshoot the set point value (cross over the set point and then create a deviation in the other direction).

1.2.4 Derivative term

The rate of change of the process error is calculated by determining the slope of the error over time (i.e. its ﬁrst derivative with respect to time) and multiplying this rate of change by the derivative gain.

The derivative term slows the rate of change of the controller output and this effect is most noticeable close to the controller set point. Hence, derivative control is used to reduce the magnitude of the overshoot produced by the integral component and improve the combined controller -process stability.

1.2.5 Loop tuning

If the PID controller parameters (the gains of the proportional, integral and derivative terms) are chosen incorrectly, the controlled process input can be unstable, i.e. its output diverges, with or without oscillation, and is limited only by saturation or mechanical breakage. Tuning a control loop is the adjustment of its control parameters (gain/proportional band, integral gain/reset, derivative gain/rate) to the optimum values for the desired control response.

1.2.6 Manual tuning

A simple tuning method is to ﬁrst set the I and D values to zero. Increase the P until the output of the loop oscillates, then the P should be set to be approximately half of that value for a "quarter amplitude decay" type response. Then increase I until any offset is correct in sufﬁcient time for the process. However, too much I will cause instability. Finally, increase D, if required, until the loop is acceptably quick to reach its reference after a load disturbance. However, too much D will cause excessive response and overshoot. A fast PID loop tuning usually overshoots slightly to reach the set point more quickly; however, some systems cannot accept overshoot, in which case an "overdamped" closed-loop system is required, which will require a P setting signiﬁcantly less than half that of the P setting causing oscillation.

1.3 RTAI

The Real Time Application Interface (RTAI) is used to provide the best Real Time (RT) performance. The RTAI patched kernel lets you write applications with strict timing constraints. RTAI gives you the ability to have things like software step generation which require precise timing.

ACPI

The Advanced Conﬁguration and Power Interface (ACPI) has a lot of different functions, most of which interfere with RT performance (for example: power management, CPU power down, CPU frequency scaling, etc). The EMC2 kernel (and probably all RTAI-patched kernels) has ACPI disabled. ACPI also takes care of powering down the system after a shutdown has been started, and that’s why you need to push the power button to completely turn off your computer.

Page 21

Part I

Conﬁguration

Page 22

Chapter 2

Hardware

2.1 Latency Test

Latency is how long it takes the PC to stop what it is doing and respond to an external request. For EMC2 the request is BASE_THREAD that makes the periodic "heartbeat" that serves as a timing reference for the step pulses. The lower the latency, the faster you can run the heartbeat, and the faster and smoother the step pulses will be.

Latency is far more important than CPU speed. A lowly Pentium II that responds to interrupts within 10 microseconds each and every time can give better results than the latest and fastest P4 Hyperthreading beast.

The CPU isn’t the only factor in determining latency. Motherboards, video cards, USB ports, and a number of other things can hurt the latency. The best way to ﬁnd out what you are dealing with is to run the RTAI latency test.

Generating step pulses in software has one very big advantage - it’s free. Just about every PC has a parallel port that is capable of outputting step pulses that are generated by the software. However, software step pulses also have some disadvantages:

• limited maximum step rate

• jitter in the generated pulses

• loads the CPU

The best way to ﬁnd out what you are dealing with is to run the HAL latency test. To run the test, open a terminal window from Applications/Accessories/Terminal (Ubuntu) and run the following command:

latency-test

You should see something like this:

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EMC V2.4 Integrator Manual Chapter 2. Hardware

While the test is running, you should "abuse" the computer. Move windows around on the screen. Surf the web. Copy some large ﬁles around on the disk. Play some music. Run an OpenGL program such as glxgears. The idea is to put the PC through its paces while the latency test checks to see what the worst case numbers are.

NOTE: Do not run EMC2 or Stepconf while the latency test is running.

The important numbers are the "max jitter". In the example above, that is 7555 nanoseconds, or

7.5 microseconds. Record this number, and enter it in Stepconf when it is requested.

In the example above, latency-test only ran for a few seconds. You should run the test for at least several minutes; sometimes the worst case latency doesn’t happen very often, or only happens when you do some particular action. For instance, one Intel motherboard worked pretty well most of the time, but every 64 seconds it had a very bad 300uS latency. Fortunately that was ﬁxable see

http://wiki.linuxcnc.org/cgi-bin/emcinfo.pl?FixingSMIIssues

So, what do the results mean? If your Max Jitter number is less than about 15-20 microseconds (15000-20000 nanoseconds), the computer should give very nice results with software stepping. If the max latency is more like 30-50 microseconds, you can still get good results, but your maximum step rate might be a little disappointing, especially if you use microstepping or have very ﬁne pitch leadscrews. If the numbers are 100uS or more (100,000 nanoseconds), then the PC is not a good candidate for software stepping. Numbers over 1 millisecond (1,000,000 nanoseconds) mean the PC is not a good candidate for EMC, regardless of whether you use software stepping or not.

Note that if you get high numbers, there may be ways to improve them. Another PC had very bad latency (several milliseconds) when using the onboard video. But a $5 used video card solved the problem - EMC does not require bleeding edge hardware.

For more information on stepper tuning see the Stepper Tuning chapter (24).

2.2 Port Address

For those who build their own hardware, one safeguard against shorting out an on-board parallel port - or even the whole motherboard - is to use an add-on parallel port card. Even if you don’t need the extra layer of safety, a parport card is a good way to add extra I/O lines with EMC.

One good PCI parport card is made with the Netmos 9815 chipset. It has good +5V signals, and can come in a single or dual ports.

To ﬁnd the I/O addresses for these cards open a terminal window and use the list pci command:

lspci -v

Look for the entry with "NetMos" in it. Example of a 2-port card:

0000:01:0a.0 Communication controller: Netmos Technology PCI 9815 Multi-I/O Controller (rev 01)

Subsystem: LSI Losgic / Symbios Logic 2POS (2 port parallel adapter) Flags: medium devsel, IRQ 5

I/O ports at b800 [size=8] I/O ports at bc00 [size=8] I/O ports at c000 [size=8] I/O ports at c400 [size=8] I/O ports at c800 [size=8] I/O ports at cc00 [size=16]

From experimentation, I’ve found the ﬁrst port (the on-card port) uses the third address listed (c000), and the second port (the one that attaches with a ribbon cable) uses the ﬁrst address listed (b800).

You can then open an editor and put the addresses into the appropriate place in your .hal ﬁle.

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EMC V2.4 Integrator Manual Chapter 2. Hardware

loadrt hal_parport cfg="0x378 0xc000"

You must also direct EMC to run the "read" and "write" functions for the second card. For example,

addf parport.1.read base-thread 1 addf parport.1.write base-thread -1

Please note that your values will differ. The Netmos cards are Plug-N-Play, and might change their settings depending on which slot you put them into, so if you like to ’get under the hood’ and re-arrange things, be sure to check these values before you start EMC.

Page 25

Chapter 3

Conﬁg Files

3.1 Files Used for Conﬁguration

The EMC is conﬁgured with human readable text ﬁles. All of these ﬁles can be read and edited in any of the common text ﬁle editors available with most any Linux distribution.1You’ll need to be a bit careful when you edit these ﬁles. Some mistakes will cause the start up to fail. These ﬁles are read whenever the software starts up. Some of them are read repeatedly while the CNC is running.

Conﬁguration ﬁles include

INI The ini ﬁle overrides defaults that are compiled into the EMC code. It also provides sections

that are read directly by the Hardware Abstraction Layer.

HAL The HAL ﬁles start up process modules and provide linkages between EMC signals and speciﬁc

hardware pins.

VAR The var ﬁle is a way for the interpreter to save some values from one run to the next. These val-

ues are saved from one run to another but not always saved immediately. See the Parameters section of the G Code Manual for information on what each parameter is.

TBL The tbl ﬁle saves tool information. See the User Manual Tool File section for more info.

NML The nml ﬁle conﬁgures the communication channels used by the EMC. It is normally setup

to run all of the communication within a single computer but can be modiﬁed to communicate between several computers.

.emcrc This ﬁle saves user speciﬁc information and is created to save the name of the directory

when the user ﬁrst selects an EMC conﬁguration.

Items marked (H AL) are used only by the sample HAL ﬁles and are suggested as a good convention. Other items are used by EMC directly, and must always have the section and item names given.

Don’t confuse a text editor with a word processor. A text editor like gedit or kwrite produce ﬁles that are plain text. They also produce lines of text that are separated from each other. A word processor like Open Ofﬁce produce ﬁles with paragraphs and word wrapping and lots of embedded codes that control font size and such. A text editor does none of this.

Usually this ﬁle is in the users home directory (e.g. /home/user/ )

Page 26

Chapter 4

INI File

4.1 The INI File Layout

A typical INI ﬁle follows a rather simple layout that includes;

• comments.

• sections,

• variables.

Each of these elements is separated on single lines. Each end of line or newline character creates a new element.

4.1.1 Comments

A comment line is started with a ; or a # mark. When the ini reader sees either of these marks at the start a line, the rest of the line is ignored by the software. Comments can be used to describe what some INI element will do.

; This is my little mill configuration file. ; I set it up on January 12, 2006

Comments can also be used to select between several values of a single variable.

DISPLAY = axis # DISPLAY = touchy

In this list, the DISPLAY variable will be set to axis because the other one is commented out. If someone carelessly edits a list like this and leaves two of the lines uncommented, the ﬁrst one encountered will be used.

Note that inside a variable, the "#" and ";" characters do not denote comments:

INCORRECT = value # and a comment # Correct Comment CORRECT = value

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EMC V2.4 Integrator Manual Chapter 4. INI File

4.1.2 Sections

Related parts of an ini ﬁle are separated into sections. A section line looks like [THIS_SECTION]. The name of the section is enclosed in brackets. The order of sections is unimportant. The following sections are used by EMC:

• [EMC] general information (4.2.1)

• [DISPLAY] settings related to the graphical user interface (4.2.2)

• [FILTER] settings input ﬁlter programs ([sub:[FILTER]-Section])

• [RS274NGC] settings used by the g-code interpreter (4.2.4)

• [EMCMOT] settings used by the real time motion controller (4.2.5)

• [HAL] speciﬁes .hal ﬁles (4.2.7)

• [TASK] settings used by the task controller (4.2.6)

• [TRAJ] additional settings used by the real time motion controller (4.2.8)

• [AXIS_0] ... [AXIS_n] individual axis variables (4.2.9)

• [EMCIO] settings used by the I/O Controller (4.2.10)

• [HALUI] MDI commands used by HALUI. See the HALUI chapter for more information (10.2.12)

4.1.3 Variables

A variable line is made up of a variable name, an equals sign(=), and a value. Everything from the ﬁrst non-white space character after the = up to the end of the line is passed as the value, so you can embed spaces in string symbols if you want to or need to. A variable name is often called a keyword.

The following sections detail each section of the conﬁguration ﬁle, using sample values for the conﬁguration lines.

Some of the variables are used by EMC, and must always use the section names and variable names shown. Other variables are used only by HAL, and the section names and variable names shown are those used in the sample conﬁguration ﬁles.

4.1.4 Deﬁnitions

Machine Unit The unit of measurement for an axis is determined by the settings in the [TRAJ] sec-

tion. A machine unit is equal to one unit as speciﬁed by LINEAR_UNITS or ANGULAR_UNITS.

4.2 Sections

4.2.1 [EMC] Section

VERSION = $Revision: 1.3 $ The version number for the INI ﬁle. The value shown here looks odd

because it is automatically updated when using the Revision Control System. It’s a good idea to change this number each time you revise your ﬁle. If you want to edit this manually just change the number and leave the other tags alone.

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EMC V2.4 Integrator Manual Chapter 4. INI File

MACHINE = My Controller This is the name of the controller, which is printed out at the top of

most graphical interfaces. You can put whatever you want here as long as you make it a single line long.

DEBUG = 0 Debug level 0 means no messages will be printed when EMC is run from a terminal.

Debug ﬂags are usually only useful to developers. See src/emc/nml_int/emcglb.h for other settings.

4.2.2 [DISPLAY] Section

Different user interface programs use different options, and not every option is supported by every user interface. The main two interfaces for EMC are AXIS and Touchy. Axis is an interface for use with normal computer and monitor, Touchy is for use with touch screens. Descriptions of the interfaces are in the Interfaces section of the User Manual.

DISPLAY = axis The name of the user interface to use. Valid options may include:

• axis

• touchy

• keystick

• mini

• tkemc

• xemc

POSITION_OFFSET = RELATIVE The coordinate system (RELATIVE or MACHINE) to show when

the user interface starts. The RELATIVE coordinate system reﬂects the G92 and G5x coordinate offsets currently in effect.

POSITION_FEEDBACK = ACTUAL The coordinate value (COMMANDED or ACTUAL) to show when

the user interface starts. The COMMANDED position is the ideal position requested by EMC. The ACTUAL position is the feedback position of the motors.

MAX_FEED_OVERRIDE = 1.2 The maximum feed override the user may select. 1.2 means 120%

of the programmed feed rate

MIN_SPINDLE_OVERRIDE = 0.5 The minimum spindle override the user may select. 0.5 means

50% of the programmed spindle speed. (This is useful as it’s dangerous to run a program with a too low spindle speed).

MAX_SPINDLE_OVERRIDE = 1.0 The maximum spindle override the user may select. 1.0 means

100% of the programmed spindle speed

PROGRAM_PREFIX = ~/emc2/nc_ﬁles The default location for g-code ﬁles and the location for

user-deﬁned M-codes

INTRO_GRAPHIC = emc2.gif The image shown on the splash screen

INTRO_TIME = 5 The maximum time to show the splash screen

CYCLE_TIME = 0.0500 Cycle time in seconds that display will sleep between polls.

The following [DISPLAY] items are used only if you select AXIS as your user interface program.

DEFAULT_LINEAR_VELOCITY = .25 The default velocity for linear jogs, in machine units per sec-

ond.

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EMC V2.4 Integrator Manual Chapter 4. INI File

MIN_VELOCITY = .01 The approximate lowest value the jog slider.

MAX_LINEAR_VELOCITY = 1.0 The maximum velocity for linear jogs, in machine units per sec-

ond.

MIN_LINEAR_VELOCITY = .01 The approximate lowest value the jog slider.

DEFAULT_ANGULAR_VELOCITY = .25 The default velocity for angular jogs, in machine units per

second.

MIN_ANGULAR_VELOCITY = .01 The approximate lowest value the jog slider.

MAX_ANGULAR_VELOCITY = 1.0 The maximum velocity for angular jogs, in machine units per

second.

INCREMENTS = 1 mm, .5 in, ... Deﬁnes the increments available for incremental jogs. The IN-

CREMENTS can be used to override the default. The values can be decimal numbers (e.g.,

0.1000) or fractional numbers (e.g., 1/16), optionally followed by a unit (cm, mm, um, inch, in or mil). If a unit is not speciﬁed the machine unit is assumed. Metric and imperial distances may be mixed: INCREMENTS = 1 inch, 1 mil, 1 cm, 1 mm, 1 um is a valid entry.

OPEN_FILE = /full/path/to/ﬁle.ngc The ﬁle to show in the preview plot when AXIS starts. Use a

blank string "" and no ﬁle will be loaded at start up.

EDITOR = gedit The editor to use when selecting File > Edit or File Edit Tool Table from the AXIS

menu. This must be conﬁgured for these menu items to work. Another valid entry is gnometerminal -e vim.

PYVCP = /ﬁlename.xml The pyVCP panel description ﬁle. See the pyVCP section for more infor-

mation.

LATHE = 1 This displays in lathe mode with a top view and with Radius and Diameter on the DRO.

GEOMETRY = XYZABCUVW Controls the preview and backplot of rotary motion. This item con-

sists of a sequence of axis letters, optionally preceded by a "-" sign. Only axes deﬁned in [TRAJ]AXES should be used. This sequence speciﬁes the order in which the effect of each axis is applied, with a "-" inverting the sense of the rotation. The proper GEOMETRY string depends on the machine conﬁguration and the kinematics used to control it. The example string GEOMETRY=XYZBCUVW is for a 5-axis machine where kinematics causes UVW to move in the coordinate system of the tool and XYZ to move in the coordinate system of the material. The order of the letters is important, because it expresses the order in which the different transformations are applied. For example rotating around C then B is different than rotating around B then C. Geometry has no effect without a rotary axis.

ARCDIVISION = 64 Set the quality of preview of arcs. Arcs are previewed by dividing them into

a number of straight lines; a semicircle is divided into ARCDIVISION parts. Larger values give a more accurate preview, but take longer to load and result in a more sluggish display. Smaller values give a less accurate preview, but take less time to load and may result in a faster display. The default value of 64 means a circle of up to 3 inches will be displayed to within 1 mil (.03%).

The following [DISPLAY] items are not used if you select AXIS as your user interface program.

HELP_FILE = tkemc.txt Path to help ﬁle (not used in AXIS).

In emc2.4 and earlier, the default value was 128.

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4.2.3 [FILTER] Section

AXIS has the ability to send loaded ﬁles through a ﬁlter program. This ﬁlter can do any desired task: Something as simple as making sure the ﬁle ends with M2, or something as complicated as detecting whether the input is a depth image, and generating g-code to mill the shape it deﬁnes. The [FILTER] section of the ini ﬁle controls how ﬁlters work. First, for each type of ﬁle, write a PROGRAM_EXTENSION line. Then, specify the program to execute for each type of ﬁle. This program is given the name of the input ﬁle as its ﬁrst argument, and must write rs274ngc code to standard output. This output is what will be displayed in the text area, previewed in the display area, and executed by EMC when Run.

PROGRAM_EXTENSION = .extension Description

If your post processor outputs ﬁles in all caps you might want to add the following line:

PROGRAM_EXTENSION = .NGC XYZ Post Processor

The following lines add support for the image-to-gcode converter included with EMC2:

PROGRAM_EXTENSION = .png,.gif Greyscale Depth Image png = image-to-gcode gif = image-to-gcode

It is also possible to specify an interpreter:

PROGRAM_EXTENSION = .py Python Script py = python

In this way, any Python script can be opened, and its output is treated as g-code. One such example script is available at nc_ﬁles/holecircle.py. This script creates g-code for drilling a series of holes along the circumference of a circle. Many more g-code generators are on the EMC Wiki site

http://wiki.linuxcnc.org/cgi-bin/emcinfo.pl.

If the environment variable AXIS_PROGRESS_BAR is set, then lines written to stderr of the form

FILTER_PROGRESS=%d

Sets the AXIS progress bar to the given percentage. This feature should be used by any ﬁlter that runs for a long time.

4.2.4 [RS274NGC] Section

PARAMETER_FILE = ﬁle.var The ﬁle which contains the parameters used by the interpreter (saved

between runs).

RS274NGC_STARTUP_CODE = G21 G90 A string of NC codes that the interpreter is initialized

with. This is not a substitute for specifying modal g-codes at the top of each ngc ﬁle, because the modal codes of machines differ, and may be changed by g-code interpreted earlier in the session.

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4.2.5 [EMCMOT] Section

You may ﬁnd other entries in this section and they should not be changed.

BASE_PERIOD = 50000 (HAL) "Base" task period, in nanoseconds - this is the fastest thread in the

machine. On servo-based systems, there is generally no reason for BASE_PERIOD to be smaller than SERVO_PERIOD. On machines with software step generation, the BASE_PERIOD determines the maximum number of steps per second. In the absence of long step length and step space requirements, the absolute maximum step rate is one step per BASE_PERIOD. Thus, the BASE_PERIOD shown above gives an absolute maximum step rate of 20000 steps per second. 50000ns is a fairly conservative value. The smallest usable value is related to the Latency Test result, the necessary step length, and the processor speed. Choosing a BASE_PERIOD that is too low can lead to the "Unexpected real time delay" message, lockups, or spontaneous reboots.

SERVO_PERIOD = 1000000 (HAL) "Servo" task period is also in nanoseconds. This value will be

rounded to an integer multiple of BASE_PERIOD. This value is used even on systems based on stepper motors. This is the rate at which new motor positions are computed, following error is checked, PID output values are updated, and so on. Most systems will not need to change this value. It is the update rate of the low level motion planner.

TRAJ_PERIOD = 1000000 (HAL) Trajectory Planner task period in nanoseconds This value will be

rounded to an integer multiple of SERVO_PERIOD. Except for machines with unusual kinematics (e.g., hexapods) there is no reason to make this value larger than SERVO_PERIOD.

4.2.6 [TASK] Section

TASK = milltask Speciﬁes the name of the "task" executable. "task" does various things, such

as communicate with the UIs over NML, communicate with the realtime motion planner over non-HAL shared memory, and interpret gcode. Currently there is only one task executable that makes sense for 99.9% of users, milltask In the dim mists of time (before HAL), it was frequently the case that an integrator would have to build a modiﬁed version of things like task, io, and motion for a speciﬁc machine.

CYCLE_TIME = 0.001 The period, in seconds, at which EMCTASK will run. This parameter affects

the polling interval when waiting for motion to complete, when executing a pause instruction, and when accepting a command from a user interface. There is usually no need to change this number.

4.2.7 [HAL] section

HALFILE = example.hal Execute the ﬁle ’example.hal’ at start up. If HALFILE is speciﬁed multiple

times, the ﬁles are executed in the order they appear in the ini ﬁle. Almost all conﬁgurations will have at least one HALFILE, and stepper systems typically have two such ﬁles, one which speciﬁes the generic stepper conﬁguration (core_stepper.hal) and one which speciﬁes the machine pin out (xxx_pinout.hal)

HALCMD = command Execute ’command’ as a single hal command. If HALCMD is speciﬁed mul-

tiple times, the commands are executed in the order they appear in the ini ﬁle. HALCMD lines are executed after all HALFILE lines.

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SHUTDOWN = shutdown.hal Execute the ﬁle ’shutdown.hal’ when EMC is exiting. Depending on

the hardware drivers used, this may make it possible to set outputs to deﬁned values when EMC is exited normally. However, because there is no guarantee this ﬁle will be executed (for instance, in the case of a computer crash) it is not a replacement for a proper physical e-stop chain or other protections against software failure.

POSTGUI_HALFILE = example2.hal (Only with the AXIS GUI) Execute ’example2.hal’ after the GUI

has created its HAL pins. See section 12.4 for more information.

4.2.8 [TRAJ] Section

The [TRAJ] section contains general parameters for the trajectory planning module in EMCMOT.

COORDINATES = X Y Z The names of the axes being controlled. X, Y, Z, A, B, C, U, V, and W are

all valid. Only axis named in COORDINATES are accepted in g-code. This has no effect on the mapping from G-code axis names (X- Y- Z-) to joint numbers–for "trivial kinematics", X is always joint 0, A is always joint 4, and U is always joint 7, and so on. It is permitted to write an axis name twice (e.g., X Y Y Z for a gantry machine) but this has no effect.

AXES = 3 One more than the number of the highest joint number in the system. For an XYZ

machine, the joints are numbered 0, 1 and 2; in this case AXES should be 3. For an XYUV machine using "trivial kinematics", the V joint is numbered 7 and therefore AXES should be 8. For a machine with nontrivial kinematics (e.g., scarakins) this will generally be the number of controlled joints.

HOME = 0 0 0 Coordinates of the homed position of each axis. Again for a fourth axis you will need

0 0 0 0. This value is only used for machines with nontrivial kinematics. On machines with trivial kinematics this value is ignored.

LINEAR_UNITS = <units> Speciﬁes the machine units for linear axes. Possible choices are (in,

inch, imperial, metric, mm). This does not affect the linear units in NC code (the G20 and G21 words do this).

ANGULAR_UNITS = <units> Speciﬁes the machine units for rotational axes. Possible choices are

’deg’, ’degree’ (360 per circle), ’rad’, ’radian’ (2pi per circle), ’grad’, or ’gon’ (400 per circle). This does not affect the angular units of NC code. In RS274NGC, A-, B- and C- words are always expressed in degrees.

DEFAULT_VELOCITY = 0.0167 The initial rate for jogs of linear axes, in machine units per second.

The value shown equals one unit per minute.

DEFAULT_ACCELERATION = 2.0 In machines with nontrivial kinematics, the acceleration used

for "teleop" (Cartesian space) jogs, in machine units per second per second.

MAX_VELOCITY = 5.0 The maximum velocity for any axis or coordinated move, in machine units

per second. The value shown equals 300 units per minute.

MAX_ACCELERATION = 20.0 The maximum acceleration for any axis or coordinated axis move,

in machine units per second per second.

POSITION_FILE = position.txt If set to a non-empty value, the joint positions are stored between

runs in this ﬁle. This allows the machine to start with the same coordinates it had on shutdown. This assumes there was no movement of the machine while powered off. If unset, joint positions are not stored and will begin at 0 each time EMC is started. This can help on smaller machines without home switches.

NO_FORCE_HOMING = 1 The default behavior is for EMC to force the user to home the machine

before any MDI command or a program is run. Normally jogging only is allowed before homing.

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Setting NO_FORCE_HOMING = 1 allows the user to make MDI moves and run programs without homing the machine ﬁrst. Interfaces without homing ability will need to have this option set to 1. Warning: Using this will allow the machine to run past soft limits while in operation and is not generally desirable to allow this.

4.2.9 [AXIS_<num>] Section

The [AXIS_0], [AXIS_1], etc. sections contains general parameters for the individual components in the axis control module. The axis section names begin numbering at 0, and run through the number of axes speciﬁed in the [TRAJ] AXES entry minus 1.

• AXIS_0 = X

• AXIS_1 = Y

• AXIS_2 = Z

• AXIS_3 = A

• AXIS_4 = B

• AXIS_5 = C

• AXIS_6 = U

• AXIS_7 = V

• AXIS_8 = W

TYPE = LINEAR The type of axes, either LINEAR or ANGULAR.

WRAPPED_ROTARY = 1 When this is set to 1 for an ANGULAR axis the axis will move 0-359.999

degrees. Plus Numbers will move the axis in a positive direction and minus numbers will move the axis in the opposite direction.

UNITS = inch If speciﬁed, this setting overrides the related [TRAJ] UNITS setting.

(e.g., [TRAJ]LINEAR_UNITS if the TYPE of this axis is LINEAR, [TRAJ]ANGULAR_UNITS if the TYPE of this axis is ANGULAR)

MAX_VELOCITY = 1.2 Maximum velocity for this axis in machine units per second.

MAX_ACCELERATION = 20.0 Maximum acceleration for this axis in machine units per second

squared.

BACKLASH = 0.000 Backlash in machine units. Backlash compensation value can be used to

make up for small deﬁciencies in the hardware used to drive an axis. If backlash is added to an axis and you are using steppers the STEPGEN_MAXACCEL must be increased to 1.5 to 2 times the MAX_ACCELERATION for the axis.

COMP_FILE = ﬁle.extension A ﬁle holding compensation structure for the axis. The ﬁle could

be named xscrew.comp for example for the X axis. File names are case sensitive and can contain letters and or numbers. The values are triplets per line separated by a space. The ﬁrst value is nominal (where it should be). The second and third values depend on the setting of COMP_FILE_TYPE. Currently the limit inside EMC2 is for 256 triplets per axis. If COMP_FILE is speciﬁed, BACKLASH is ignored. Compensation ﬁle values are in machine units.

• COMP_FILE_TYPE=0 the second and third values specify the forward position (where the axis is while traveling forward) and reverse position (where the axis is while traveling reverse) positions which correspond to the nominal position.

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• COMP_FILE_TYPE=1 the second and third values specify the forward trim (how far from nominal while traveling forward) and the reverse trim (how far from nominal while traveling in reverse).

COMP_FILE_TYPE = 0 For COMP_FILE_TYPE of zero, the values in the compensation ﬁle are nom-

inal, forward & reverse. For COMP_FILE_TYPE of non-zero the values in the compensation ﬁle are nominal, forward_trim and reverse_trim.

MIN_LIMIT = -1000 The minimum limit (soft limit) for axis motion, in machine units. When this

limit is exceeded, the controller aborts axis motion.

MAX_LIMIT = 1000 The maximum limit (soft limit) for axis motion, in machine units. When this

limit is exceeded, the controller aborts axis motion.

MIN_FERROR = 0.010 This is the value in machine units by which the axis is permitted to deviate

from commanded position at very low speeds. If MIN_FERROR is smaller than FERROR, the two produce a ramp of error trip points. You could think of this as a graph where one dimension is speed and the other is permitted following error. As speed increases the amount of following error also increases toward the FERROR value.

FERROR = 1.0 FERROR is the maximum allowable following error, in machine units. If the differ-

ence between commanded and sensed position exceeds this amount, the controller disables servo calculations, sets all the outputs to 0.0, and disables the ampliﬁers. If MIN_FERROR is present in the .ini ﬁle, velocity-proportional following errors are used. Here, the maximum allowable following error is proportional to the speed, with FERROR applying to the rapid rate set by [TRAJ]MAX_VELOCITY, and proportionally smaller following errors for slower speeds. The maximum allowable following error will always be greater than MIN_FERROR. This prevents small following errors for stationary axes from inadvertently aborting motion. Small following errors will always be present due to vibration, etc. The following polarity values determine how inputs are interpreted and how outputs are applied. They can usually be set via trial-and-error since there are only two possibilities. The EMC2 Servo Axis Calibration utility program (in the AXIS interface menu Machine/Calibration and in TkEMC it is under Setting/Calibration) can be used to set these and more interactively and verify their results so that the proper values can be put in the INI ﬁle with a minimum of trouble.

4.2.9.1 Homing

These parameters are Homing related, for a better explanation read the Homing Section (4.3).

HOME = 0.0 The position that the joint will go to upon completion of the homing sequence.

HOME_OFFSET = 0.0 The axis position of the home switch or index pulse, in machine units.

HOME_SEARCH_VEL = 0.0 Initial homing velocity in machine units per second. Sign denotes di-

rection of travel. A value of zero means assume that the current location is the home position for the machine. If your machine has no home switches you will want to leave this value alone.

HOME_LATCH_VEL = 0.0 Homing velocity in machine units per second to the home switch latch

position. Sign denotes direction of travel.

HOME_FINAL_VEL = 0.0 Velocity in machine units per second from home latch position to home

position. If left at 0 or not included in the axis rapid velocity is used. Must be a positive number.

HOME_USE_INDEX = NO If the encoder used for this axis has an index pulse, and the motion card

has provision for this signal you may set it to yes. When it is yes, it will affect the kind of home pattern used. Currently, you can’t home to index with steppers unless your using stepgen in velocity mode and pid.

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HOME_IGNORE_LIMITS = NO Some machines use a single switch as a home switch and limit

switch. This variable should be set to yes if the machine conﬁgured this way.

HOME_IS_SHARED = <n> If the home input is shared by more than one axis set <n> to 1 to prevent

homing from starting if the one of the shared switches is already closed. Set <n> to 0 to permit homing if a switch is closed.

HOME_SEQUENCE = <n> Used to deﬁne the "Home All" sequence. <n> starts at 0 and no numbers

may be skipped. If left out or set to -1 the joint will not be homed by the "Home All" function. More than one axis can be homed at the same time.

VOLATILE_HOME = 0 When enabled (set to 1) this joint will be unhomed if the Machine Power is

off or if E-Stop is on. This is useful if your machine has home switches and does not have position feedback such as a step and direction driven machine.

4.2.9.2 Servo

The following items are for servo-based systems and servo-like systems. This description assumes that the units of output from the PID component are volts.

DEADBAND = 0.000015 (HAL) How close is close enough the consider the motor in position.

BIAS = 0.000 (HAL) This is used by hm2-servo and some others. Bias is a constant amount that

is added to the output. In most cases it should be left at zero. However, it can sometimes be useful to compensate for offsets in servo ampliﬁers, or to balance the weight of an object that moves vertically. bias is turned off when the PID loop is disabled, just like all other components of the output.

P = 50 (HAL) The proportional gain for the axis servo. This value multiplies the error between

commanded and actual position in machine units, resulting in a contribution to the computed voltage for the motor ampliﬁer. The units on the P gain are volts per machine unit, e.g.,

volt

I = 0 (HAL) The integral gain for the axis servo. The value multiplies the cumulative error between

commanded and actual position in machine units, resulting in a contribution to the computed voltage for the motor ampliﬁer. The units on the I gain are volts per machine unit second, e.g.,

volt

mu s

D = 0 (HAL) The derivative gain for the axis servo. The value multiplies the difference between the

current and previous errors, resulting in a contribution to the computed voltage for the motor ampliﬁer. The units on the D gain are volts per machine unit per second, e.g.,

volt

mu/s

FF0 = 0 (HAL) The 0th order feed forward gain. This number is multiplied by the commanded

position, resulting in a contribution to the computed voltage for the motor ampliﬁer. The units on the FF0 gain are volts per machine unit, e.g.,

volt

FF1 = 0 (HAL) The 1st order feed forward gain. This number is multiplied by the change in com-

manded position per second, resulting in a contribution to the computed voltage for the motor ampliﬁer. The units on the FF1 gain are volts per machine unit per second, e.g.,

volt

mu s

FF2 = 0 (HAL) The 2nd order feed forward gain. This number is multiplied by the change in com-

manded position per second per second, resulting in a contribution to the computed voltage for the motor ampliﬁer. The units on the FF2 gain are volts per machine unit per second per second, e.g.,

volt

mu s

OUTPUT_SCALE = 1.000

OUTPUT_OFFSET = 0.000 (HAL) These two values are the scale and offset factors for the axis

output to the motor ampliﬁers. The second value (offset) is subtracted from the computed output (in volts), and divided by the ﬁrst value (scale factor), before being written to the D/A converters. The units on the scale value are in true volts per DAC output volts. The units on

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the offset value are in volts. These can be used to linearize a DAC. Speciﬁcally, when writing outputs, the EMC ﬁrst converts the desired output in quasi-SI units to raw actuator values, e.g., volts for an ampliﬁer DAC. This scaling looks like:

raw =

output − off set

scale

The value for scale can be obtained analytically by doing a unit analysis, i.e., units are [output SI units]/[actuator units]. For example, on a machine with a velocity mode ampliﬁer such that 1 volt results in 250 mm/sec velocity,

amplif ier[volts] = (output[

] − off set[

sec

])/250

sec volt

Note that the units of the offset are in machine units, e.g., mm/sec, and they are presubtracted from the sensor readings. The value for this offset is obtained by ﬁnding the value of your output which yields 0.0 for the actuator output. If the DAC is linearized, this offset is normally 0.0. The scale and offset can be used to linearize the DAC as well, resulting in values that reﬂect the combined effects of ampliﬁer gain, DAC non-linearity, DAC units, etc. To do this, follow this procedure:

1. Build a calibration table for the output, driving the DAC with a desired voltage and measuring the result. See table 4.2.9.2 for an example of voltage measurements.

2. Do a least-squares linear ﬁt to get coefﬁcients a, b such that

meas = a ∗ raw + b

3. Note that we want raw output such that our measured result is identical to the commanded output. This means

(a)

cmd = a ∗ raw + b

(b)

raw = (cmd − b)/a

4. As a result, the a and b coefﬁcients from the linear ﬁt can be used as the scale and offset for the controller directly.

MAX_OUTPUT = 10 (HAL) The maximum value for the output of the PID compensation that is

written to the motor ampliﬁer, in volts. The computed output value is clamped to this limit. The limit is applied before scaling to raw output units. The value is applied symmetrically to both the plus and the minus side.

Output Voltage Measurements

Raw Measured

-10 -9.93

-9 -8.83 0 -0.03 1 0.96 9 9.87

10 10.87

INPUT_SCALE = 20000 (HAL) Speciﬁes the number of pulses that corresponds to a move of one

machine unit as set in the [TRAJ] section. For a linear axis one machine unit will be equal to the setting of LINEAR_UNITS. For an angular axis one unit is equal to the setting in ANGULAR_UNITS.

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A second number, if speciﬁed, is ignored. For example, on a 2000 counts per rev encoder, and 10 revs/inch gearing, and desired units of inch, we have

input_scale = 2000

= 20000

4.2.9.3 Stepper

The following items are Stepper related items.

SCALE = 4000 (HAL) Speciﬁes the number of pulses that corresponds to a move of one machine

unit as set in the [TRAJ] section. For stepper systems, this is the number of step pulses issued per machine unit. For a linear axis one machine unit will be equal to the setting of LINEAR_UNITS. For an angular axis one unit is equal to the setting in ANGULAR_UNITS. For servo systems, this is the number of feedback pulses per machine unit. A second number, if speciﬁed, is ignored. For example, on a 1.8 degree stepper motor with half-stepping, and 10 revs/inch gearing, and desired machine units of inch, we have

input_scale =

2 steps

1.8 degree

= 4000

counts

rev

counts

inch

∗ 360

steps

inch

∗ 10

degree

rev

inch

∗ 10

rev

inch

Older stepper conﬁguration .ini and .hal used INPUT_SCALE for this value.

STEPGEN_MAXACCEL = 21.0 (HAL) Acceleration limit for the step generator. This should be 1%

to 10% larger than the axis MAX_ACCELERATION. This value improves the tuning of stepgen’s "position loop". If you have added backlash compensation to an axis then this should be 1.5 to 2 times greater than MAX_ACCELERATION.

STEPGEN_MAXVEL = 1.4 (HAL) Older conﬁguration ﬁles have a velocity limit for the step gener-

ator as well. If speciﬁed, it should also be 1% to 10% larger than the axis MAX_VELOCITY. Subsequent testing has shown that use of STEPGEN_MAXVEL does not improve the tuning of stepgen’s position loop.

4.2.10 [EMCIO] Section

CYCLE_TIME = 0.100 The period, in seconds, at which EMCIO will run. Making it 0.0 or a negative

number will tell EMCIO not to sleep at all. There is usually no need to change this number.

TOOL_TABLE = tool.tbl The ﬁle which contains tool information, described in the User Manual.

TOOL_CHANGE_POSITION = 0 0 2 Speciﬁes the X Y Z location to move to when performing a tool

change if three digits are used. Speciﬁes the X Y Z A B C location when 6 digits are used. Speciﬁes the X Y Z A B C U V W location when 9 digits are used. Tool Changes can be combined. For example if you combine the quill up with change position you can move the Z ﬁrst then the X and Y.

TOOL_CHANGE_WITH_SPINDLE_ON = 1 The spindle will be left on during the tool change when

the value is 1. Useful for lathes or machines where the material is in the spindle not the tool.

TOOL_CHANGE_QUILL_UP = 1 The Z axis will be moved to machine zero prior to the tool change

when the value is 1. This is the same as issuing a G0 G53 Z0.

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TOOL_CHANGE_AT_G30 = 1 The machine is moved to reference point deﬁned by parameters 5181-

5186 for G30 if the value is 1. For more information on G30 and Parameters see the G Code Manual.

RANDOM_TOOLCHANGER = 1 This is for machines that cannot place the tool back into the pocket

it came from. For example, machines that exchange the tool in the active pocket with the tool in the spindle.

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4.3 Homing

4.3.1 Overview

Homing seems simple enough - just move each joint to a known location, and set EMC’s internal variables accordingly. However, different machines have different requirements, and homing is actually quite complicated.

4.3.2 Homing Sequence

There are four possible homing sequences, along with the associated conﬁguration parameters as shown in the following table. For a more detailed description of what each conﬁguration parameter does, see the following section.

SEARCH_VEL LATCH_VEL USE_INDEX Homing Type

nonzero nonzero NO Switch-only nonzero nonzero YES Switch + Index

0 nonzero YES Index-only 0 0 NO None

Other combinations Error

4.3.3 Conﬁguration

There are six pieces of information that determine exactly how the home sequence behaves. They are deﬁned in an [AXIS] section of the iniﬁle.

4.3.3.1 HOME_SEARCH_VEL

The default value is zero. A value of zero causes EMC to assume that there is no home switch; the search stage of homing is skipped.

If HOME_SEARCH_VEL is non-zero, then EMC assumes that there is a home switch. It begins by checking whether the home switch is already tripped. If tripped it backs off the switch at HOME_SEARCH_VEL. The direction of the back-off is opposite the sign of HOME_SEARCH_VEL. Then it searches for the home switch by moving in the direction speciﬁed by the sign of HOME_SEARCH_VEL, at a speed determined by its absolute value. When the home switch is detected, the joint will stop as fast as possible, but there will always be some overshoot. The amount of overshoot depends on the speed. If it is too high, the joint might overshoot enough to hit a limit switch or crash into the end of travel. On the other hand, if HOME_SEARCH_VEL is too low, homing can take a long time.

4.3.3.2 HOME_LATCH_VEL

Speciﬁes the speed and direction that EMC uses when it makes its ﬁnal accurate determination of the home switch (if present) and index pulse location (if present). It will usually be slower than the search velocity to maximise accuracy. If HOME_SEARCH_VEL and HOME_LATCH_VEL have the same sign, then the latch phase is done while moving in the same direction as the search phase. (In that case, EMC ﬁrst backs off the switch, before moving towards it again at the latch velocity.) If HOME_SEARCH_VEL and HOME_LATCH_VEL have opposite signs, the latch phase is done while moving in the opposite direction from the search phase. That means EMC will latch the ﬁrst pulse after it moves off the switch. If HOME_SEARCH_VEL is zero (meaning there is no home switch), and this parameter is nonzero, EMC goes ahead to the index pulse search. If HOME_SEARCH_VEL is non-zero and this parameter is zero, it is an error and the homing operation will fail. The default value is zero.

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4.3.3.3 HOME_FINAL_VEL

It speciﬁes the speed that EMC uses when it makes its move from HOME_OFFSET to the HOME position. If the HOME_FINAL_VEL is missing from the ini ﬁle, then the maximum joint speed is used to make this move. The value must a positive number.

4.3.3.4 HOME_IGNORE_LIMITS

Can hold the values YES / NO. This ﬂag determines whether EMC will ignore the limit switch inputs. Some machine conﬁgurations do not use a separate home switch, instead they route one of the limit switch signals to the home switch input as well. In this case, EMC needs to ignore that limit during homing. The default value for this parameter is NO.

4.3.3.5 HOME_USE_INDEX

Speciﬁes whether or not there is an index pulse. If the ﬂag is true (HOME_USE_INDEX = YES), EMC will latch on the rising edge of the index pulse. If false, EMC will latch on either the rising or falling edge of the home switch (depending on the signs of HOME_SEARCH_VEL and HOME_LATCH_VEL). The default value is NO.

4.3.3.6 HOME_OFFSET

Contains the location of the home switch or index pulse, in joint coordinates. It can also be treated as the distance between the point where the switch or index pulse is latched and the zero point of the joint. After detecting the index pulse, EMC sets the joint coordinate of the current point to HOME_OFFSET. The default value is zero.

4.3.3.7 HOME

The position that the joint will go to upon completion of the homing sequence. After detecting the index pulse, and setting the coordinate of that point to HOME_OFFSET, EMC makes a move to HOME as the ﬁnal step of the homing process. The default value is zero. Note that even if this parameter is the same as HOME_OFFSET, the axis will slightly overshoot the latched position as it stops. Therefore there will always be a small move at this time (unless HOME_SEARCH_VEL is zero, and the entire search/latch stage was skipped). This ﬁnal move will be made at the joint’s maximum velocity. Since the axis is now homed, there should be no risk of crashing the machine, and a rapid move is the quickest way to ﬁnish the homing sequence.

4.3.3.8 HOME_IS_SHARED

If there is not a separate home switch input for this axis, but a number of momentary switches wired to the same pin, set this value to 1 to prevent homing from starting if one of the shared switches is already closed. Set this value to 0 to permit homing even if the switch is already closed.

The distinction between ’home’ and ’home_offset’ is not as clear as I would like. I intend to make a small drawing and

example to help clarify it.

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EMC V2.4 Integrator Manual Chapter 4. INI File

4.3.3.9 HOME_SEQUENCE

Used to deﬁne a multi-axis homing sequence HOME ALL and enforce homing order (e.g., Z may not be homed if X is not yet homed). An axis may be homed after all axes with a lower HOME_SEQUENCE have already been homed and are at the HOME_OFFSET. If two axes have the same HOME_SEQUENCE, they may be homed at the same time. If HOME_SEQUENCE is -1 or not speciﬁed then this joint will not be homed by the HOME ALL sequence. HOME_SEQUENCE numbers start with 0 and there may be no unused numbers.

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EMC V2.4 Integrator Manual Chapter 4. INI File

INDEX PULSES

HOME SWITCH TRIPS

SEARCH FOR HOME SWITCH (SEARCH_VEL)

BACK OFF OF HOME SWITCH (SEARCH_VEL)

FINAL DETECTION OF SWITCH (LATCH_VEL)

FINAL DETECTION OF SWITCH AND

INDEX PULSE (LATCH_VEL)

FINAL DETECTION OF SWITCH (LATCH_VEL)

FINAL DETECTION OF SWITCH AND

INDEX PULSE (LATCH_VEL)

GO TO HOME POSITION (MAX_VEL)

1.000

3.000

SEARCH_VEL = POSITIVE

LATCH_VEL = NEGATIVE

LATCH_VEL = POSITIVE

USE_INDEX = FALSE

USE_INDEX = TRUE

USE_INDEX = FALSE

USE_INDEX = TRUE

HOME_OFFSET = 3.000

HOME = 1.000

OVERSHOOT

HOME SWITCH RELEASES

Figure 4.1: Homing Sequences

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EMC V2.4 Integrator Manual Chapter 4. INI File

4.4 Lathe

4.4.1 Default Plane

When EMC’s interpreter was ﬁrst written, it was designed for mills. That is why the default plane is XY (G17). A normal lathe only uses the XZ plane (G18). To change the default plane place the following line in the .ini ﬁle in the RS274NGC section.

RS274NGC_STARTUP_CODE = G18

4.4.2 INI Settings

The following .ini settings are needed for lathe mode in addition to or replacing normal settings in the .ini ﬁle.

[DISPLAY] DISPLAY = axis LATHE = 1 [TRAJ] AXES = 3 COORDINATES = X Z [AXIS_0] ... [AXIS_2] ...

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EMC2 and HAL

See also the manual pages motion(9) and iocontrol(1).

5.1 motion (realtime)

5.1.1 Options

Motion is loaded with the motmod command. A kins should be loaded before motion.

loadrt motmod [base_period_nsec=period] [servo_period_nsec=period] [traj_period_nsec=period] [num_joints=[0-9] ([num_dio=1-64] num_aio=1-16])]

If the number of digital I/O needed is above the default of 4 you can add up to 64 digital I/O by using the num_dio option when loading motmod.

If the number of analog I/O needed is more that the default of 4 you can add up to 16 analog I/O by using the num_aio option when loading motmod.

5.1.2 Pins

These pins, parameters, and functions are created by the realtime motmod module.

motion.adaptive-feed (ﬂoat, in) When adaptive feed is enabled with M52 P1, the commanded ve-

locity is multiplied by this value. This effect is multiplicative with the NML-level feed override value and motion.feed-hold.

motion.analog-in-00 (ﬂoat, in) These pins (00, 01, 02, 03 or more if conﬁgured) are controlled by

M66.

motion.analog-out-00 (ﬂoat, out) These pins (00, 01, 02, 03 or more if conﬁgured) are controlled

by M67 or M68.

motion.coord-error (bit, out) TRUE when motion has encountered an error, such as exceeding a

soft limit

motion.coord-mode (bit, out) TRUE when motion is in "coordinated mode", as opposed to "teleop

mode"

motion.current-vel (ﬂoat, out) The current tool velocity in user units per second.

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motion.digital-in-00 (bit, in) These pins (00, 01, 02, 03 or more if conﬁgured) are controlled by

M62-65.

motion.digital-out-00 (bit, out) These pins (00, 01, 02, 03 or more if conﬁgured) are controlled by

the M62-65.

motion.distance-to-go (ﬂoat,out) The distance remaining in the current move.

motion.enable (bit, in) If this bit is driven FALSE, motion stops, the machine is placed in the

"machine off" state, and a message is displayed for the operator. For normal motion, drive this bit TRUE.

motion.feed-hold (bit, in) When Feed Stop Control is enabled with M53 P1, and this bit is TRUE,

the feed rate is set to 0.

motion.in-position (bit, out) TRUE if the machine is in position.

motion.motion-enabled (bit, out) TRUE when in "machine on" state.

motion.on-soft-limit (bit, out) TRUE when the machine is on a soft limit.

motion.probe-input (bit, in) G38.x uses the value on this pin to determine when the probe has

made contact. TRUE for probe contact closed (touching), FALSE for probe contact open.

motion.program-line (s32, out) The current program line while executing. Zero if not running or

between lines while single stepping.

motion.requested-vel (ﬂoat, out) The current requested velocity in user units per second from the

F=n setting in the G Code ﬁle. No feed overrides or any other adjustments are applied to this pin.

motion.spindle-at-speed (bit, in) Motion will pause until this pin is TRUE, under the following

conditions: before the ﬁrst feed move after each spindle start or speed change; before the start of every chain of spindle-synchronized moves; and if in CSS mode, at every rapid to feed transition. This input can be used to ensure that the spindle is up to speed before starting a cut, or that a lathe spindle in CSS mode has slowed down after a large to small facing pass before starting the next pass at the large diameter. Many VFDs have an "at speed" output. Otherwise, it is easy to generate this signal with the HAL near component, by comparing requested and actual spindle speeds.

motion.spindle-brake (bit, out) TRUE when the spindle brake should be applied.

motion.spindle-forward (bit, out) TRUE when the spindle should rotate forward.

motion.spindle-index-enable (bit, I/O) For correct operation of spindle synchronized moves, this

pin must be hooked to the index-enable pin of the spindle encoder.

motion.spindle-on (bit, out) TRUE when spindle should rotate.

motion.spindle-reverse (bit, out) TRUE when the spindle should rotate backward

motion.spindle-revs (ﬂoat, in) For correct operation of spindle synchronized moves, this signal

must be hooked to the position pin of the spindle encoder. The spindle encoder position should be scaled such that spindle-revs increases by 1.0 for each rotation of the spindle in the clockwise (M3) direction.

motion.spindle-speed-in (ﬂoat, in) Feedback of actual spindle speed in rotations per second. This

is used by feed-per-revolution motion (G95). If your spindle encoder driver does not have a velocity output, you can generate a suitable one by sending the spindle position through a ddt component.

motion.spindle-speed-out (ﬂoat, out) Commanded spindle speed in rotations per minute. Positive

for spindle forward (M3), negative for spindle reverse (M4).

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motion.spindle-speed-out-rps (ﬂoat, out) Commanded spindle speed in rotations per second. Pos-

itive for spindle forward (M3), negative for spindle reverse (M4).

motion.teleop-mode (bit, out) TRUE when motion is in "teleop mode", as opposed to "coordinated

mode"

motion.tooloffset.w (ﬂoat, out) shows the w offset in effect; it could come from the tool table (G43

active), or it could come from the gcode (G43.1 active)

motion.tooloffset.x (ﬂoat, out) shows the x offset in effect; it could come from the tool table (G43

active), or it could come from the gcode (G43.1 active)

motion.tooloffset.z (ﬂoat, out) shows the z offset in effect; it could come from the tool table (G43

active), or it could come from the gcode (G43.1 active)

5.1.3 Parameters

Many of these parameters serve as debugging aids, and are subject to change or removal at any time.

motion-command-handler.time (s32, RO)

motion-command-handler.tmax (s32, RW)

motion-controller.time (s32, RO)

motion-controller.tmax (s32, RW)

motion.debug-bit-0 (bit, RO) This is used for debugging purposes.

motion.debug-bit-1 (bit, RO) This is used for debugging purposes.

motion.debug-ﬂoat-0 (ﬂoat, RO) This is used for debugging purposes.

motion.debug-ﬂoat-1 (ﬂoat, RO) This is used for debugging purposes.

motion.debug-ﬂoat-2 (ﬂoat, RO) This is used for debugging purposes.

motion.debug-ﬂoat-3 (ﬂoat, RO) This is used for debugging purposes.

motion.debug-s32-0 (s32, RO) This is used for debugging purposes.

motion.debug-s32-1 (s32, RO) This is used for debugging purposes.

motion.servo.last-period (u32, RO) The number of CPU cycles between invocations of the servo

thread. Typically, this number divided by the CPU speed gives the time in seconds, and can be used to determine whether the realtime motion controller is meeting its timing constraints

motion.servo.last-period-ns (ﬂoat, RO)

motion.servo.overruns (u32, RW) By noting large differences between successive values of motion.servo.last-

period, the motion controller can determine that there has probably been a failure to meet its timing constraints. Each time such a failure is detected, this value is incremented.

5.1.4 Functions

Generally, these functions are both added to the servo-thread in the order shown.

motion-command-handler Processes motion commands coming from user space

motion-controller Runs the EMC motion controller

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5.2 axis.N (realtime)

These pins and parameters are created by the realtime motmod module. These are actually joint values, but the pins and parameters are still called "axis.N".1They are read and updated by the motion-controller function.

5.2.1 Pins

axis.N.active (bit, out)

axis.N.amp-enable-out (bit, out) TRUE if the ampliﬁer for this joint should be enabled

axis.N.amp-fault-in (bit, in) Should be driven TRUE if an external fault is detected with the ampli-

ﬁer for this joint

axis.N.backlash-corr (ﬂoat, out)

axis.N.backlash-ﬁlt (ﬂoat, out)

axis.N.backlash-vel (ﬂoat, out)

axis.N.coarse-pos-cmd (ﬂoat, out)

axis.N.error (bit, out)

axis.N.f-error (ﬂoat, out)

axis.N.f-error-lim (ﬂoat, out)

axis.N.f-errored (bit, out)

axis.N.faulted (bit, out)

axis.N.free-pos-cmd (ﬂoat, out)

axis.N.free-tp-enable (bit, out)

axis.N.free-vel-lim (ﬂoat, out)

axis.N.home-sw-in (bit, in) Should be driven TRUE if the home switch for this joint is closed.

axis.N.homed (bit, out)

axis.N.homing (bit, out) TRUE if the joint is currently homing

axis.N.in-position (bit, out)

axis.N.index-enable (bit, I/O)

axis.N.jog-counts (s32, in) Connect to the "counts" pin of an external encoder to use a physical jog

wheel.

axis.N.jog-enable (bit, in) When TRUE (and in manual mode), any change in "jog-counts" will result

in motion. When false, "jog-counts" is ignored.

axis.N.jog-scale (ﬂoat, in) Sets the distance moved for each count on "jog-counts", in machine

units.

axis.N.jog-vel-mode (bit, in) When FALSE (the default), the jogwheel operates in position mode.

The axis will move exactly jog-scale units for each count, regardless of how long that might take. When TRUE, the wheel operates in velocity mode - motion stops when the wheel stops, even if that means the commanded motion is not completed.

In "trivial kinematics" machines, there is a one-to-one correspondence between joints and axes.

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axis.N.joint-pos-cmd (ﬂoat, out) The joint (as opposed to motor) commanded position. There may

be an offset between the joint and motor positions–for example, the homing process sets this offset.

axis.N.joint-pos-fb (ﬂoat, out) The joint (as opposed to motor) feedback position.

axis.N.joint-vel-cmd (ﬂoat, out)

axis.N.kb-jog-active (bit, out)

axis.N.motor-pos-cmd (ﬂoat, out) The commanded position for this joint.

axis.N.motor-pos-fb (ﬂoat, in) The actual position for this joint.

axis.N.neg-hard-limit (bit, out)

axis.N.pos-lim-sw-in (bit, in) Should be driven TRUE if the positive limit switch for this joint is

closed

axis.N.pos-hard-limit (bit, out)

axis.N.neg-lim-sw-in (bit, in) Should be driven TRUE if the negative limit switch for this joint is

closed

axis.N.wheel-jog-active (bit, out)

5.2.2 Parameters

axis.N.home-state Reﬂects the step of homing currently taking place

5.3 iocontrol (userspace)

These pins are created by the userspace IO controller, usually called io.

5.3.1 Pins

iocontrol.0.coolant-ﬂood (bit, out) TRUE when ﬂood coolant is requested

iocontrol.0.coolant-mist (bit, out) TRUE when mist coolant is requested

iocontrol.0.emc-enable-in (bit, in) Should be driven FALSE when an external E-Stop condition

exists

iocontrol.0.lube (bit, out) TRUE when lube is commanded

iocontrol.0.lube_level (bit, in) Should be driven TRUE when lube level is high enough

iocontrol.0.tool-change (bit, out) TRUE when a tool change is requested

iocontrol.0.tool-changed (bit, in) Should be driven TRUE when a tool change is completed

iocontrol.0.tool-number (s32, out) The current tool number

iocontrol.0.tool-prep-number (s32, out) The number of the next tool, from the RS274NGC T-word

iocontrol.0.tool-prepare (bit, out) TRUE when a tool prepare is requested

iocontrol.0.tool-prepared (bit, in) Should be driven TRUE when a tool prepare is completed

iocontrol.0.user-enable-out (bit, out) FALSE when an internal E-Stop condition exists

iocontrol.0.user-request-enable (bit, out) TRUE when the user has requested that E-Stop be

cleared

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Part II

HAL

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Chapter 6

Getting Started

6.1 Hal Commands

More detailed information can be found in the man page for halcmd "man halcmd" in a terminal window. To see the HAL conﬁguration and check the status of pins and parameters use the HAL Conﬁguration window on the Machine menu in AXIS. To watch a pin status open the Watch tab and click on each pin you wish to watch and it will be added to the watch window.

Figure 6.1: HAL Conﬁguration Window

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6.1.1 loadrt

The command "loadrt" loads a real time HAL component. Real time component functions need to be added to a thread to be updated at the rate of the thread. You cannot load a user space component into the real time space.

The syntax and an example:

loadrt <component> <options> loadrt mux4 count=1

6.1.2 addf

The command "addf" adds a real time component function to a thread. You have to add a function from a HAL real time component to a thread to get the function to update at the rate of the thread.

If you used the Stepper Conﬁg Wizard to generate your conﬁg you will have two threads.

• base-thread (the high-speed thread): this thread handles items that need a fast response, like making step pulses, and reading and writing the parallel port.

• servo-thread (the slow-speed thread): this thread handles items that can tolerate a slower response, like the motion controller, ClassicLadder, and the motion command handler.

The syntax and an example:

addf <component> <thread> addf mux4 servo-thread

6.1.3 loadusr

The command "loadusr" loads a user space HAL component. User space programs are their own separate processes, which optionally talk to other HAL components via pins and parameters. You cannot load real time components into user space.

Flags may be one or more of the following:

-W to wait for the component to become ready. The component is assumed to have the same name

as the ﬁrst argument of the command.

-Wn <name> to wait for the component, which will have the given <name>.

-w to wait for the program to exit

-i to ignore the program return value (with -w)

The syntax and examples:

loadusr <component> <options> loadusr halui loadusr -Wn spindle gs2_vfd -n spindle in English it means "loadusr wait for name spindle component gs2_vfd name spindle." the -n spindle is part of the gs2_vfd component not the loadusr command.

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6.1.4 net

The command "net" creates a "connection" between a signal and and one or more pins. If the signal does not exist net creates the new signal. This replaces the need to use the command newsig. The direction indicators "<= and =>" are only to make it easier for humans to follow the logic and are not used by the net command.

The syntax and an example:

net <signal-name> <pin-name> <opt-direction> <opt-pin-name> net both-home-y <= parport.0.pin-11-in

Each signal can only have one source (a HAL "Dir out” pin) and as many readers (a HAL "Dir in" pin) as you like. In the Dir column of the HAL Conﬁguration window you can see which pins are "in" and which are "out". The following ﬁgure shows the "direction" of the signal from the source, through the signal, and then out to the reader(s).

Figure 6.2: Signal Direction

This example shows the signal xStep with the source being stepgen.0.out and with two readers, parport.0.pin-02-out and parport.0.pin-08-out. Basically the value of stepgen.0.out is send to the signal xStep and that value is then sent to parport.0.pin-02-out and parport.0.pin-08-out.

signal source destination destination

net xStep stepgen.0.out => parport.0.pin-02-out parport.0.pin-08-out

Since the signal xStep contains the value of stepgen.0.out (the source) you can use the same signal again to send the value to another reader. To do this just use the signal with the readers on another line.

net xStep <= stepgen.0.out => parport.0.pin-02-out net xStep => parport.0.pin-08-out

The so called I/O pins like index-enable do not follow this rule.

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6.1.5 setp

The command "setp" sets the value of a pin or parameter. The valid values will depend on the type of the pin or parameter. It is an error if the data types do not match.

Some components have parameters that need to be set before use. Parameters can be set before use or while running as needed. You cannot use setp on a pin that is connected to a signal.

The syntax and an example:

setp <pin/parameter-name> <value> setp parport.0.pin-08-out TRUE

6.1.6 unlinkp

The command "unlinkp" unlinks a pin from the connected signal. If no signal was connected to the pin prior running the command, nothing happens.

The syntax and an example:

unlinkp <pin-name> unlinkp parport.0.pin-02-out

6.1.7 Obsolete Commands

6.1.7.1 linksp

The command "linksp" creates a "connection" between a signal and one pin.

The syntax and an example:

linksp <signal-name> <pin-name> linksp X-step parport.0.pin-02-out

The "linksp" command has been superseded by the "net" command.

6.1.7.2 linkps

The command "linkps" creates a "connection" between one pin and one signal. It is the same as linksp but the arguments are reversed.

The syntax and an example:

linkps <pin-name> <signal-name> linkps parport.0.pin-02-out X-Step

The "linkps" command has been superseded by the "net" command.

6.1.7.3 newsig

the command "newsig" creates a new HAL signal by the name <signame> and the data type of <type>. Type must be "bit", "s32", "u32" or "ﬂoat". Error if <signame> all ready exists.

The syntax and an example:

newsig <signame> <type> newsig Xstep bit

More information can be found in the HAL manual or the man pages for halrun.

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6.2 Hal Data

6.2.1 Bit

A bit value is an on or off.

• bit values = true or 1 and false or 0 (True, TRUE, true are all valid)

6.2.2 Float

A "ﬂoat" is a ﬂoating point number. In other words the decimal point can move as needed.

• ﬂoat values = a 32 bit ﬂoating point value, with approximately 24 bits of resolution and over 200 bits of dynamic range.

For more information on ﬂoating point numbers see:

http://en.wikipedia.org/wiki/Floating_point

6.2.3 s32

An "s32" number is a whole number that can have a negative or positive value.

• s32 values = integer numbers -2147483648 to 2147483647

6.2.4 u32

A "u32" number is a whole number that is positive only.

• u32 values = integer numbers 0 to 4294967295

6.3 Hal Files

If you used the Stepper Conﬁg Wizard to generate your conﬁg you will have up to three HAL ﬁles in your conﬁg directory.

• my-mill.hal (if your conﬁg is named "my-mill") This ﬁle is loaded ﬁrst and should not be changed if you used the Stepper Conﬁg Wizard.

• custom.hal This ﬁle is loaded next and before the GUI loads. This is where you put your custom HAL commands that you want loaded before the GUI is loaded.

• custom_postgui.hal This ﬁle is loaded after the GUI loads. This is where you put your custom HAL commands that you want loaded after the GUI is loaded. Any HAL commands that use pyVCP widgets need to be placed here.

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6.4 HAL Components

Two parameters are automatically added to each HAL component when it is created. These parameters allow you to scope the execution time of a component.

.time .tmax

Time is the number of CPU cycles it took to execute the function.

Tmax is the maximum number of CPU cycles it took to execute the function. Tmax is a read/write parameter so the user can set it to 0 to get rid of the ﬁrst time initialization on the function’s execution time.

6.5 Logic Components

Hal contains several real time logic components. Logic components follow a "Truth Table" that states what the output is for any given input. Typically these are bit manipulators and follow electrical logic gate truth tables.

6.5.1 and2

The "and2" component is a two input "and" gate. The truth table below shows the output based on each combination of input.

Syntax

and2 [count=N] or [names=name1[,name2...]]

Functions

and2.n

Pins

and2.N.in0 (bit, in) and2.N.in1 (bit, in) and2.N.out (bit, out)

Truth Table

in0 in1 out

False False False

True False False

False True False

True True True

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EMC V2.4 Integrator Manual Chapter 6. Getting Started

6.5.2 not

The "not" component is a bit inverter.

Syntax

not [count=n] or [names=name1[,name2...]]

Functions

not.all not.n

Pins

not.n.in (bit, in) not.n.out (bit, out)

Truth Table

in out

True False

False True

6.5.3 or2

The "or2" component is a two input OR gate.

Syntax

or2[count=n] or [names=name1[,name2...]]

Functions

or2.n

Pins

or2.n.in0 (bit, in) or2.n.in1 (bit, in) or2.n.out (bit, out)

in0 in1 out

True False True

True True True False True True False False False

Truth Table

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EMC V2.4 Integrator Manual Chapter 6. Getting Started

6.5.4 xor2

The "xor2" component is a two input XOR (exclusive OR)gate.

Syntax

xor2[count=n] or [names=name1[,name2...]]

Functions

xor2.n

Pins

xor2.n.in0 (bit, in) xor2.n.in1 (bit, in) xor2.n.out (bit, out)

Truth Table

in0 in1 out

True False True

True True False False True True False False False

6.5.5 Logic Examples

An "and2" example connecting two inputs to one output.

loadrt and2 count=1 addf and2.0 servo-thread net my-sigin1 and2.0.in0 <= parport.0.pin-11-in net my-sigin2 and2.0.in1 <= parport.0.pin-12-in net both-on parport.0.pin-14-out <= and2.0.out

In the above example one copy of and2 is loaded into real time space and added to the servo thread. Next pin 11 of the parallel port is connected to the in0 bit of the and gate. Next pin 12 is connected to the in1 bit of the and gate. Last we connect the and2 out bit to the parallel port pin 14. So following the truth table for and2 if pin 11 and pin 12 are on then the output pin 14 will be on.

6.6 Conversion Components

6.6.1 weighted_sum

The weighted_sum converts a group of bits to an integer. The conversion is the sum of the "weights" of the bits that are on plus any offset. This is similar to a binary coded decimal but with more options. The "hold" bit stops processing the input changes so the "sum" will not change.

The following syntax is used to load the weighted_sum component.

loadrt weighted_sum wsum_sizes=size[,size,...]

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EMC V2.4 Integrator Manual Chapter 6. Getting Started

Creates weighted sum groups each with the given number of input bits (size).

To update the weighted_sum you need to attach process_wsums to a thread.

addf process_wsums servo-thread

This updates the weighted_sum component.

In the following example clipped from the HAL Conﬁguration window in Axis the bits "0" and "2" are true and there is no offset. The "weight" of 0 is 1 and the "weight" of 2 is 4 so the sum is 5.

Figure 6.3: weighted_sum

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6.7 Halshow

The script halshow can help you ﬁnd your way around a running HAL. This is a very specialized system and it must connect to a working HAL. It cannot run standalone because it relies on the ability of HAL to report what it knows of itself through the halcmd interface library. It is discovery based. Each time halshow runs with a different EMC conﬁguration it will be different.

As we will soon see, this ability of HAL to document itself is one key to making an effective CNC system.

6.7.1 Starting Halshow

Halshow is in the AXIS menu under Machine/Show Hal Conﬁguration.

Halshow is in the TkEMC menu under Scripts/Hal Show.

6.7.2 Hal Tree Area

At the left of its display as shown in ﬁgure 6.4 is a tree view, somewhat like you might see with some ﬁle browsers. At the right is a tabbed notebook with tabs for show and watch.

Figure 6.4: Halshow Layout

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The tree shows all of the major parts of a HAL. In front of each is a small plus (+) or minus (-) sign in a box. Clicking the plus will expand that tree node to display what is under it. If that box shows a minus sign, clicking it will collapse that section of the tree.

You can also expand or collapse the tree display using the Tree View menu at the upper left edge of the display. Under Tree View you will ﬁnd: Expand Tree, Collapse Tree; Expand Pins, Expand Parameters, Expand Signals; and Erase Watch. (Note that Erase Watch erasesall previously set watches, you cannot erase just one watch.)

Figure 6.5: Show Menu

6.7.3 Hal Show Area

Clicking on the node name, the word "Components" for example, will show you (under the "Show" tab) all that hal knows about the contents of that node. Figure 6.4 shows a list exactly like you will see if you click the "Components" name while you are running a standard m5i20 servo card. The information display is exactly like those shown in traditional text based HAL analysis tools. The advantage here is that we have mouse click access, access that can be as broad or as focused as you need.

If we take a closer look at the tree display we can see that the six major parts of a HAL can all be expanded at least one level. As these levels are expanded you can get more focused with the reply when you click on the rightmost tree node. You will ﬁnd that there are some hal pins and parameters that show more than one reply. This is due to the nature of the search routines in halcmd itself. If you search one pin you may get two, like this:

Component Pins: Owner Type Dir Value Name 06 bit -W TRUE parport.0.pin-10-in 06 bit -W FALSE parport.0.pin-10-in-not

The second pin’s name contains the complete name of the ﬁrst.

Below the show area on the right is a set of widgets that will allow you to play with the running HAL. The commands you enter here and the effect that they have on the running HAL are not saved. They will persist as long as EMC remains up but are gone as soon as EMC is.

The entry box labeled "Test Hal Command:" will accept any of the commands listed for halcmd. These include:

• loadrt, unloadrt (load/unload real-time module)

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• loadusr, unloadusr (load/unload user-space component)

• addf, delf (add/delete a function to/from a real-time thread)

• net (create a connection between two or more items)

• setp (set parameter (or pin) to a value)

This little editor will enter a command any time you press <enter> or push the execute button. An error message from halcmd will show below this entry widget when these commands are not properly formed. If you are not certain how to set up a proper command you’ll need to read again the documentation on halcmd and the speciﬁc modules that you are working with.

Let’s use this editor to add a differential module to a hal and connect it to axis position so that we could see the rate of change in position, i.e., acceleration. We ﬁrst need to load a hal module named blocks, add it to the servo thread, then connect it to the position pin of an axis. Once that is done we can ﬁnd the output of the differentiator in halscope. So let’s go. (Yes, I looked this one up.)

loadrt blocks ddt=1

Now look at the components node and you should see blocks in there someplace.

Loaded HAL Components: ID Type Name 10 User halcmd29800 09 User halcmd29374 08 RT blocks 06 RT hal_parport 05 RT scope_rt 04 RT stepgen 03 RT motmod 02 User iocontrol

Sure enough there it is. Notice that its ID is 08. Next we need to ﬁnd out what functions are available with it so we look at functions:

Exported Functions: Owner CodeAddr Arg FP Users Name 08 E0B97630 E0DC7674 YES 0 ddt.0 03 E0DEF83C 00000000 YES 1 motion-command-handler 03 E0DF0BF3 00000000 YES 1 motion-controller 06 E0B541FE E0DC75B8 NO 1 parport.0.read 06 E0B54270 E0DC75B8 NO 1 parport.0.write 06 E0B54309 E0DC75B8 NO 0 parport.read-all 06 E0B5433A E0DC75B8 NO 0 parport.write-all 05 E0AD712D 00000000 NO 0 scope.sample 04 E0B618C1 E0DC7448 YES 1 stepgen.capture-position 04 E0B612F5 E0DC7448 NO 1 stepgen.make-pulses 04 E0B614AD E0DC7448 YES 1 stepgen.update-freq

Here we look for owner #08 and see that blocks has exported a function named ddt.0. We should be able to add ddt.0 to the servo thread and it will do its math each time the servo thread is updated. Once again we look up the addf command and ﬁnd that it uses three arguments like this:

addf <functname> <threadname> [<position>]

We already know the functname=ddt.0 so let’s get the thread name right by expanding the thread node in the tree. Here we see two threads, servo-thread and base-thread. The position of ddt.0 in the thread is not critical. So we add the function ddt.0 to the servo-thread:

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addf ddt.0 servo-thread

This is just for viewing, so we leave position blank and get the last position in the thread. Figure 6.6 shows the state of halshow after this command has been issued.

Figure 6.6: Addf Command

Next we need to connect this block to something. But how do we know what pins are available? The answer is to look under pins. There we ﬁnd ddt and see this:

Component Pins: Owner Type Dir Value Name 08 ﬂoat R- 0.00000e+00 ddt.0.in 08 ﬂoat -W 0.00000e+00 ddt.0.out

That looks easy enough to understand, but what signal or pin do we want to connect to it? It could be an axis pin, a stepgen pin, or a signal. We see this when we look at axis.0:

Component Pins: Owner Type Dir Value Name 03 ﬂoat -W 0.00000e+00 axis.0.motor-pos-cmd ==> Xpos-cmd

So it looks like Xpos-cmd should be a good signal to use. Back to the editor where we enter the following command:

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linksp Xpos-cmd ddt.0.in

Now if we look at the Xpos-cmd signal using the tree node we’ll see what we’ve done:

Signals: Type Value Name ﬂoat 0.00000e+00 Xpos-cmd <== axis.0.motor-pos-cmd ==> ddt.0.in ==> stepgen.0.position-cmd

We see that this signal comes from axis.o.motor-pos-cmd and goes to both ddt.0.in and stepgen.0.positioncmd. By connecting our block to the signal we have avoided any complications with the normal ﬂow of this motion command.

The Hal Show Area uses halcmd to discover what is happening in a running HAL. It gives you complete information about what it has discovered. It also updates as you issue commands from the little editor panel to modify that HAL. There are times when you want a different set of things displayed without all of the information available in this area. That is where the Hal Watch Area is of value.

6.7.4 Hal Watch Area

Clicking the watch tab produces a blank canvas. You can add signals and pins to this canvas and watch their values.1You can add signals or pins when the watch tab is displayed by clicking on the name of it. Figure 6.7 shows this canvas with several "bit" type signals. These signals include enable-out for the ﬁrst three axes and two of the three iocontrol "estop" signals. Notice that the axes are not enabled even though the estop signals say that EMC is not in estop. A quick look at TkEMC shows that the condition of EMC is ESTOP RESET. The amp enables do not turn true until the machine has been turned on.

The refresh rate of the watch display is much lower than Halmeter or Halscope. If you need good resolution of the timing

of signals those tools are much more effective.

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Figure 6.7: Watch Display

Watch displays bit type (binary) values using colored circles representing LEDs. They show as dark brown when a bit signal or pin is false, and as light yellow whenever that signal is true. If you select a pin or signal that is not a bit type (binary) signal, watch will show it as a numerical value.

Watch will quickly allow you to test switches or see the effect of changes that you make to EMC while using the graphical interface. Watch’s refresh rate is a bit slow to see stepper pulses, but you can use it for these if you move an axis very slowly or in very small increments of distance. If you’ve used IO_Show in EMC, the watch page in halshow can be set up to watch a parport much as IO_Show did.

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Chapter 7

Basic Conﬁguration

7.1 Introduction

The preferred way to set up a standard stepper machine is with the Step Conﬁguration Wizard. See the Getting Started Guide.

This chapter describes some of the more common settings for manually setting up a stepper based system. Because of the various possibilities of conﬁguring EMC2, it is very hard to document them all, and keep this document relatively short.

The most common EMC2 usage is for stepper based systems. These systems are using stepper motors with drives that accept step & direction signals.

It is one of the simpler setups, because the motors run open-loop (no feedback comes back from the motors), yet the system needs to be conﬁgured properly so the motors don’t stall or lose steps.

Most of this chapter is based on the sample conﬁg released along with EMC2. The conﬁg is called stepper, and usually it is found in /etc/emc2/sample-configs/stepper.

7.2 Maximum step rate

With software step generation, the maximum step rate is one step per two BASE_PERIODs for stepand-direction output. The maximum requested step rate is the product of an axis’ MAX_VELOCITY and its INPUT_SCALE. If the requested step rate is not attainable, following errors will occur, particularly during fast jogs and G0 moves.

If your stepper driver can accept quadrature input, use this mode. With a quadrature signal, one step is possible for each BASE_PERIOD, doubling the maximum step rate.

The other remedies are to decrease one or more of: the BASE_PERIOD (setting this too low will cause the machine to become unresponsive or even lock up), the INPUT_SCALE (if you can select different step sizes on your stepper driver, change pulley ratios, or leadscrew pitch), or the MAX_VELOCITY and STEPGEN_MAXVEL.

If no valid combination of BASE_PERIOD, INPUT_SCALE, and MAX_VELOCITY is acceptable, then consider using hardware step generation (such as with the emc2-supported Universal Stepper Controller, Mesa cards, and others.)

7.3 Pinout

One of the major ﬂaws in EMC was that you couldn’t specify the pinout without recompiling the source code. EMC2 is far more ﬂexible, and now (thanks to the Hardware Abstraction Layer) you

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can easily specify which signal goes where. See the HAL manual for more detailed information on HAL.

As it is described in the HAL Introduction and tutorial, we have signals, pins and parameters inside the HAL.

The ones relevant for our pinout are1:

signals: Xstep, Xdir & Xen pins: parport.0.pin-XX-out & parport.0.pin-XX-in

Depending on what you have chosen in your .ini ﬁle you are using either standard_pinout.hal or xylotex_pinout.hal. These are two ﬁles that instruct the HAL how to link the various signals & pins. Further on we’ll investigate the standard_pinout.hal.

7.3.1 standard_pinout.hal

This ﬁle contains several HAL commands, and usually looks like this:

# standard pinout config file for 3-axis steppers # using a parport for I/O # # first load the parport driver loadrt hal_parport cfg="0x0378" # # next connect the parport functions to threads # read inputs first addf parport.0.read base-thread 1 # write outputs last addf parport.0.write base-thread -1 # # finally connect physical pins to the signals net Xstep => parport.0.pin-03-out net Xdir => parport.0.pin-02-out net Ystep => parport.0.pin-05-out net Ydir => parport.0.pin-04-out net Zstep => parport.0.pin-07-out net Zdir => parport.0.pin-06-out

# create a signal for the estop loopback net estop-loop iocontrol.0.user-enable-out iocontrol.0.emc-enable-in

# create signals for tool loading loopback net tool-prep-loop iocontrol.0.tool-prepare iocontrol.0.tool-prepared net tool-change-loop iocontrol.0.tool-change iocontrol.0.tool-changed

# connect "spindle on" motion controller pin to a physical pin net spindle-on motion.spindle-on => parport.0.pin-09-out

### ### You might use something like this to enable chopper drives when machine ON ### the Xen signal is defined in core_stepper.hal ###

Note: we are only presenting one axis to keep it short, all others are similar.

Refer to section 9.1 for additional information

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# net Xen => parport.0.pin-01-out

### ### If you want active low for this pin, invert it like this: ###

# setp parport.0.pin-01-out-invert 1

### ### A sample home switch on the X axis (axis 0). make a signal, ### link the incoming parport pin to the signal, then link the signal ### to EMC’s axis 0 home switch input pin ###

# net Xhome parport.0.pin-10-in => axis.0.home-sw-in

### ### Shared home switches all on one parallel port pin? ### that’s ok, hook the same signal to all the axes, but be sure to ### set HOME_IS_SHARED and HOME_SEQUENCE in the ini file. See the ### user manual! ###

# net homeswitches <= parport.0.pin-10-in # net homeswitches => axis.0.home-sw-in # net homeswitches => axis.1.home-sw-in # net homeswitches => axis.2.home-sw-in

### ### Sample separate limit switches on the X axis (axis 0) ###

# net X-neg-limit parport.0.pin-11-in => axis.0.neg-lim-sw-in # net X-pos-limit parport.0.pin-12-in => axis.0.pos-lim-sw-in

### ### Just like the shared home switches example, you can wire together ### limit switches. Beware if you hit one, EMC will stop but can’t tell ### you which switch/axis has faulted. Use caution when recovering from this. ###

# net Xlimits parport.0.pin-13-in => axis.0.neg-lim-sw-in axis.0.pos-lim-sw-in

The ﬁles starting with ’#’ are comments, and their only purpose is to guide the reader through the ﬁle.

7.3.2 Overview of the standard_pinout.hal

There are a couple of operations that get executed when the standard_pinout.hal gets executed / interpreted:

1. The Parport driver gets loaded (see 9.1 for details)

2. The read & write functions of the parport driver get assigned to the base thread

the fastest thread in the EMC2 setup, usually the code gets executed every few microseconds

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3. The step & direction signals for axes X,Y,Z get linked to pins on the parport

4. Further IO signals get connected (estop loopback, toolchanger loopback)

5. A spindle-on signal gets deﬁned and linked to a parport pin

7.3.3 Changing the standard_pinout.hal

If you want to change the standard_pinout.hal ﬁle, all you need is a text editor. Open the ﬁle and locate the parts you want to change.

If you want for example to change the pin for the X-axis Step & Directions signals, all you need to do is to change the number in the ’parport.0.pin-XX-out’ name:

net Xstep parport.0.pin-03-out net Xdir parport.0.pin-02-out

can be changed to:

net Xstep parport.0.pin-02-out net Xdir parport.0.pin-03-out

or basically any other numbers you like.

Hint: make sure you don’t have more than one signal connected to the same pin.

7.3.4 Changing the polarity of a signal

If external hardware expects an “active low” signal, set the corresponding -invert parameter. For instance, to invert the spindle control signal:

setp parport.0.pin-09-invert TRUE

7.3.5 Adding PWM Spindle Speed Control

If your spindle can be controlled by a PWM signal, use the pwmgen component to create the signal:

loadrt pwmgen output_type=0 addf pwmgen.update servo-thread addf pwmgen.make-pulses base-thread net spindle-speed-cmd motion.spindle-speed-out => pwmgen.0.value net spindle-on motion.spindle-on => pwmgen.0.enable net spindle-pwm pwmgen.0.pwm => parport.0.pin-09-out setp pwmgen.0.scale 1800 # Change to your spindle’s top speed in RPM

This assumes that the spindle controller’s response to PWM is simple: 0% PWM gives 0 RPM, 10% PWM gives 180 RPM, etc. If there is a minimum PWM required to get the spindle to turn, follow the example in the nist-lathe sample conﬁguration to use a scale component.

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7.3.6 Adding an enable signal

Some ampliﬁers (drives) require an enable signal before they accept and command movement of the motors. For this reason there are already deﬁned signals called ’Xen’, ’Yen’, ’Zen’.

To connect them use the following example:

net Xen parport.0.pin-08-out

You can either have one single pin that enables all drives; or several, depending on the setup you have. Note, however, that usually when one axis faults, all the other drives will be disabled as well, so having only one enable signal / pin for all drives is a common practice.

7.3.7 Adding an external ESTOP button

As you can see in 7.3.1 by default the stepper conﬁguration assumes no external ESTOP button.

To add a simple external button you need to replace the line:

net estop-loop iocontrol.0.user-enable-out iocontrol.0.emc-enable-in

with

net estop-loop parport.0.pin-01-in iocontrol.0.emc-enable-in

This assumes an ESTOP switch connected to pin 01 on the parport. As long as the switch will stay pushed5, EMC2 will be in the ESTOP state. When the external button gets released EMC2 will imediately switch to the ESTOP-RESET state, and all you need to do is switch to Machine On and you’ll be able to continue your work with EMC2.

An extensive explanation of hooking up ESTOP circuitry is explained in the wiki.linuxcnc.org and in the Integrator

Manual

make sure you use a maintained switch for ESTOP.

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Chapter 8

HAL Components

8.1 Commands and Userspace Components

Some of these will have expanded descriptions from the man pages. Some will have limited descriptions. All of the components have man pages. From this list you know what components exist and can use man n name to get additional information. For example in a terminal window type

man 1 axis

to view the information in the man page.

axis-remote.1 = AXIS Remote Interface

axis.1 = AXIS EMC (The Enhanced Machine Controller) Graphical User Interface

bﬂoad.1 = A program for loading a Xilinx Bitﬁle program into the FPGA of an Anything I/O board

from Mesa

comp.1 = Build, compile and install EMC HAL components

emc.1 = EMC (The Enhanced Machine Controller)

hal_input.1 = control HAL pins with any Linux input device, including USB HID devices

halcmd.1 = manipulate the Enhanced Machine Controller HAL from the command line

halmeter.1 = observe HAL pins, signals, and parameters

halrun.1 = manipulate the Enhanced Machine Controller HAL from the command line

halsampler.1 = sample data from HAL in realtime

halstreamer.1 = stream ﬁle data into HAL in real time

halui.1 = observe HAL pins and command EMC through NML

io.1 = accepts NML I/O commands, interacts with HAL in userspace

iocontrol.1 = accepts NML I/O commands, interacts with HAL in userspace

pyvcp.1 = Virtual Control Panel for EMC2

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8.2 Realtime Components

8.2.1 abs

Compute the absolute value and sign of the input signal

8.2.1.0.0.1 Loading

loadrt abs [count=N|names=name1[,name2...]]

8.2.1.0.0.2 Functions

addf abs.N|name thread-name

8.2.1.0.0.3 Pins

abs.N.in (float in) Input value abs.N.out (float out) Output Value, always positive abs.N.sign (bit out) Sign of Input, false = positive, true = negative

The ﬁrst abs loaded will be abs.0 and each one after that the "N" number will increment.

8.2.2 and2

Two-input AND gate. For out to be true both inputs must be true

8.2.2.0.0.4 Loading

loadrt and2 [count=N|names=name1[,name2...]]

8.2.2.0.0.5 Functions

addf and2.N|name thread-name

8.2.2.0.0.6 Pins

and2.N.in0 (bit in) Input 0 and2.N.in1 (bit in) Input 1 and2.N.out (bit out) Output

8.2.3 at_pid

proportional/integral/derivative controller with auto tuning

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8.2.4 axis

accepts NML motion commands, interacts with HAL in realtime

8.2.5 biquad

Biquad IIR ﬁlter

8.2.6 bldc_hall3

3-wire Bipolar trapezoidal commutation BLDC motor driver using Hall sensors

8.2.7 blend

Perform linear interpolation between two values

8.2.7.0.0.7 Loading

loadrt blend [count=N|names=name1[,name2...]]

8.2.7.0.0.8 Functions

addf blend.N|name thread-name

8.2.7.0.0.9 Pins

blend.N.in1 (float in) First input. blend.N.in2 (float in) Second input. blend.N.select (float in) Select input. blend.N.out (float out) Output value.

8.2.7.0.0.10 Parameters

blend.N.open (bit r/w)

8.2.7.0.0.11 Description If select is equal to 0.0 output is equal to in1.

If select is equal to 1.0, the output is equal to in2.

For select values between 0.0 and 1.0, the output changes linearly from in1 to in2.

If blend.N.open is true, select values outside the range 0.0 to 1.0 give values outside the range in1 to in2. If false, outputs are clamped to the the range in1 to in2

8.2.8 charge_pump

Create a square-wave for the "charge pump" input of some controller boards

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8.2.8.0.0.12 Loading

loadrt charge_pump

8.2.8.0.0.13 Functions

addf charge-pump

8.2.8.0.0.14 Pins

charge-pump.out (bit out) charge-pump.enable (bit in) default = TRUE

8.2.8.0.0.15 Description Outputs a square wave if enable is TRUE or unconnected, low if enable is FALSE

8.2.9 clarke2

Two input version of Clarke transform

8.2.9.0.0.16 Loading

loadrt clarke2 [count=N|names=name1[,name2...]]

8.2.9.0.0.17 Functions

addf clarke2.N | name

8.2.9.0.0.18 Pins

clarke2.N.a (float in) phase a input clarke2.N.b (float in) phase b input clarke2.N.x (float out) cartesian components of output clarke2.N.y (float out) cartesian components of output

8.2.9.0.0.19 Description The Clarke transform can be used to translate a vector quantity from a three phase system (three components 120 degrees apart) to a two phase Cartesian system.

clarke2 implements a special case of the Clarke transform, which only needs two of the three input phases. In a three wire three phase system, the sum of the three phase currents or voltages must always be zero. As a result only two of the three are needed to completely deﬁne the current or voltage. clarke2 assumes that the sum is zero, so it only uses phases A and B of the input. Since the H (homopolar) output will always be zero in this case, it is not generated.

8.2.10 clarke3

Clarke (3 phase to cartesian) transform

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8.2.10.0.0.20 Loading

loadrt clarke3 [count=N|names=name1[,name2...]]

8.2.10.0.0.21 Functions

addf clarke3.N | name

8.2.10.0.0.22 Pins

clarke3.N.a (float in) three phase input vector clarke3.N.b (float in) three phase input vector clarke3.N.c (float in) three phase input vector clarke3.N.x (float out) cartesian components of output clarke3.N.y (float out) cartesian components of output clarke3.N.h (float out) homopolar component of output

8.2.10.0.0.23 Description The Clarke transform can be used to translate a vector quantity from a three phase system (three components 120 degrees apart) to a two phase Cartesian system (plus a homopolar component if the three phases don’t sum to zero).

clarke3 implements the general case of the transform, using all three phases. If the three phases are known to sum to zero, see clarke2 for a simpler version.

8.2.11 clarkeinv

Inverse Clarke transform

8.2.11.0.0.24 Loading

loadrt clarkeinv [count=N|names=name1[,name2...]]

8.2.11.0.0.25 Functions

addf clarkeinv.N | name

8.2.11.0.0.26 Pins

clarkeinv.N.x (float in) cartesian components of input clarkeinv.N.y (float in) cartesian components of input clarkeinv.N.h (float in) homopolar component of input (usually zero) clarkeinv.N.a (float out) three phase output vector clarkeinv.N.b (float out) three phase output vector clarkeinv.N.c (float out) three phase output vector

8.2.11.0.0.27 Parameters

8.2.11.0.0.28 Description The inverse Clarke transform can be used to translate a vector quan-

tity from Cartesian coordinate system to a three phase system (three components 120 degrees apart).

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8.2.12 classicladder

Realtime software plc based on ladder logic

8.2.13 comp

Two input comparator with hysteresis

8.2.14 constant

Use a parameter to set the value of a pin

8.2.15 conv_bit_s32

Convert a value from bit to s32

8.2.16 conv_bit_u32

Convert a value from bit to u32

8.2.17 conv_ﬂoat_s32

Convert a value from ﬂoat to s32

8.2.18 conv_ﬂoat_u32

Convert a value from ﬂoat to u32

8.2.19 conv_s32_bit

Convert a value from s32 to bit

8.2.20 conv_s32_ﬂoat

Convert a value from u32 to bit

8.2.21 conv_s32_u32

Convert a value from s32 to u32

8.2.22 conv_u32_bit

Convert a value from u32 to bit

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8.2.23 conv_u32_ﬂoat

Convert a value from u32 to ﬂoat

8.2.24 conv_u32_s32

Convert a value from u32 to s32

8.2.25 counter

counts input pulses (deprecated)

8.2.26 ddt

Compute the derivative of the input function

8.2.27 deadzone

Return the center if within the threshold

8.2.28 debounce

ﬁlter noisy digital inputs, for more information see 8.9

8.2.29 edge

Edge detector

8.2.30 encoder

software counting of quadrature encoder signals, for more information see 8.6

8.2.31 encoder_ratio

an electronic gear to synchronize two axes

8.2.32 estop_latch

ESTOP latch

8.2.33 feedcomp

Multiply the input by the ratio of current velocity to the feed rate

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8.2.34 ﬂipﬂop

D type ﬂip-ﬂop

8.2.35 freqgen

software step pulse generation

8.2.36 gantrykins

A kinematics module that maps one axis to multiple joints

8.2.37 gearchange

Select from one two speed ranges

8.2.38 genhexkins

Gives six degrees of freedom in position and orientation (XYZABC). The location of the motors is deﬁned at compile time.

8.2.39 genserkins

Kinematics that can model a general serial-link manipulator with up to 6 angular joints.

8.2.40 hm2_7i43

HAL driver for the Mesa Electronics 7i43 EPP Anything IO board with HostMot2

8.2.41 hm2_pci

HAL driver for the Mesa Electronics 5i20, 5i22, 5i23, 4i65, and 4i68 Anything IO boards, with HostMot2 ﬁrmware

8.2.42 hostmot2

HAL driver for the Mesa Electronics HostMot2 ﬁrmware

8.2.43 hypot

Three-input hypotenuse (Euclidean distance) calculator

8.2.44 ilowpass

Low-pass ﬁlter with integer inputs and outputs

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8.2.45 integ

Integrator

8.2.46 invert

Compute the inverse of the input signal

8.2.47 joyhandle

sets nonlinear joypad movements, deadbands and scales

8.2.48 kins

kinematics deﬁnitions for emc2

8.2.49 knob2ﬂoat

Convert counts (probably from an encoder) to a ﬂoat value

8.2.50 limit1

Limit the output signal to fall between min and max

8.2.51 limit2

Limit the output signal to fall between min and max

8.2.52 limit3

Limit the output signal to fall between min and max

8.2.53 logic

Experimental general logic function component

8.2.54 lowpass

Low-pass ﬁlter

8.2.55 lut5

Arbitrary 5-input logic function based on a look-up table

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8.2.56 maj3

Compute the majority of 3 inputs

8.2.57 match8

8-bit binary match detector

8.2.58 maxkins

Kinematics for a tabletop 5 axis mill named "max" with tilting head (B axis) and horizintal rotary mounted to the table (C axis). Provides UVW motion in the rotated coordinate system. The source ﬁle, maxkins.c, may be a useful starting point for other 5-axis systems.

8.2.59 minmax

Track the minimum and maximum values of the input to the outputs

8.2.60 motion

accepts NML motion commands, interacts with HAL in realtime

8.2.61 mult2

Product of two inputs

8.2.62 mux2

Select from one of two input values

8.2.63 mux4

Select from one of four input values

8.2.64 mux8

Select from one of eight input values

8.2.65 near

Determine whether two values are roughly equal

8.2.66 not

Inverter

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8.2.67 offset

Adds an offset to an input, and subtracts it from the feedback value

8.2.68 oneshot

one-shot pulse generator

8.2.69 or2

Two-input OR gate

8.2.70 pid

proportional/integral/derivative controller, for more information see 8.7

8.2.71 pluto_servo

Hardware driver and ﬁrmware for the Pluto-P parallel-port FPGA, for use with servos

8.2.72 pluto_step

Hardware driver and ﬁrmware for the Pluto-P parallel-port FPGA, for use with steppers

8.2.73 pwmgen

software PWM/PDM generation, for more information see 8.5

8.2.74 rotatekins

The X and Y axes are rotated 45 degrees compared to the joints 0 and 1.

8.2.75 sample_hold

Sample and Hold

8.2.76 sampler

sample data from HAL in real time

8.2.77 scale

applies a scale and offset to its input

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8.2.78 scarakins

kinematics for SCARA-type robots

8.2.79 select8

8-bit binary match detector

8.2.80 serport

Hardware driver for the digital I/O bits of the 8250 and 16550 serial port

8.2.81 siggen

signal generator, for more information see 8.10

8.2.82 sim_encoder

simulated quadrature encoder, for more information see 8.8

8.2.83 sphereprobe

Probe a pretend hemisphere

8.2.84 stepgen

software step pulse generation, for more information see 8.4

8.2.85 steptest

Used by Stepconf to allow testing of acceleration and velocity values for an axis

8.2.86 streamer

stream ﬁle data into HAL in real time

8.2.87 sum2

Sum of two inputs (each with a gain) and an offset

8.2.88 supply

set output pins with values from parameters (deprecated)

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8.2.89 thc

Torch Height Control using a Mesa THC card.

8.2.90 threads

creates hard realtime HAL threads

8.2.91 threadtest

component for testing thread behavior

8.2.92 timedelay

The equivalent of a time-delay relay

8.2.93 timedelta

component that measures thread scheduling timing behavior

8.2.94 toggle

push-on, push-off from momentary pushbuttons

8.2.95 toggle2nist

toggle button to nist logic

8.2.96 tripodkins

The joints represent the distance of the controlled point from three predeﬁned locations (the motors), giving three degrees of freedom in position (XYZ)

8.2.97 tristate_bit

Place a signal on an I/O pin only when enabled, similar to a tristate buffer in electronics

8.2.98 tristate_ﬂoat

Place a signal on an I/O pin only when enabled, similar to a tristate buffer in electronics

8.2.99 trivkins

There is a 1:1 correspondence between joints and axes. Most standard milling machines and lathes use the trivial kinematics module.

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8.2.100 updown

Counts up or down, with optional limits and wraparound behavior

8.2.101 wcomp

Window comparator

8.2.102 weighted_sum

convert a group of bits to an integer

8.2.103 xor2

Two-input XOR (exclusive OR) gate

8.2.103.0.0.29 Loading

8.2.103.0.0.30 Functions

8.2.103.0.0.31 Pins

8.2.103.0.0.32 Parameters

8.2.103.0.0.33 Description

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8.3 Hal Meter

Hal Meter can be loaded from a terminal or from Axis. Hal Meter is faster than Hal Show displaying values. Hal Meter has two windows, one to pick the pin, signal, or parameter to monitor and one that displays the value. Multiple Hal Meters can be open at the same time. If you use a script to open multiple Hal Meters you can set the position of each one with -g X Y relative to the upper left corner of your screen. See the man page for more options.

loadusr halmeter pin hm2.0.stepgen.00.velocity-fb -g 0 500

Figure 8.1: Hal Meter

8.4 Stepgen

This component provides software based generation of step pulses in response to position or velocity commands. In position mode, it has a built in pre-tuned position loop, so PID tuning is not required. In velocity mode, it drives a motor at the commanded speed, while obeying velocity and acceleration limits. It is a realtime component only, and depending on CPU speed, etc, is capable of maximum step rates of 10kHz to perhaps 50kHz. Figure 8.2 shows three block diagrams, each is a single step pulse generator. The ﬁrst diagram is for step type ’0’, (step and direction). The second is for step type ’1’ (up/down, or pseudo-PWM), and the third is for step types 2 through 14 (various stepping patterns). The ﬁrst two diagrams show position mode control, and the third one shows velocity mode. Control mode and step type are set independently, and any combination can be selected.

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velocity-cmd

position-cmd

phase-B

phase-E

phase-D

down

step

phase-A

phase-Cupdir

pos err

vel err

counts

position-fb

maxaccel

maxfreq

position

accumulator

lookup

table

ramp

latch

state

up/down

step/dir

counter

logic

and

timing

frequency

stepspace

dirsetup

dirdelay

dirhold

steplen

rawcounts

position-scale

dddTdTstate

hold

make_pulses()

STEP TYPE = 1

STEP TYPE = 2 - 14

CTRL TYPE = VELOCITY

CTRL TYPE = POSITION

STEP TYPE = 0

update_freq()

capture_position()

stepgen.0

1/x

control

equation

Figure 8.2: Step Pulse Generator Block Diagram (position mode)

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velocity

phase-B

phase-E

phase-D

down

step

phase-A

phase-Cupdir

counts

position

maxfreq

frequency

generator

frequency

generator

frequency

generator

state

counter

lookup

table

ramp

latch

counter

step/dir

logic

and

timing

maxaccel

frequency

stepspace

dirsetup

dirhold

steplen

rawcounts

velocity-scale

position-scale

up/dn

count

make_pulses()

STEP TYPE = 1

STEP TYPE = 2 - 14

STEP TYPE = 0

make_pulses()

update_freq()

capture_position()

freqgen.0

Figure 8.3: Step Pulse Generator Block Diagram (velocity mode)

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8.4.1 Installing

emc2$ halcmd loadrt stepgen step_type=<type-array> [ctrl_type=<ctrl_array>]

<type-array> is a series of comma separated decimal integers. Each number causes a single step pulse generator to be loaded, the value of the number determines the stepping type. <ctrl_array> is a comma separated series of “p” or “v” characters, to specify position or velocity mode. ctrl_type is optional, if ommitted, all of the step generators will be position mode. For example:

emc2# halcmd loadrt stepgen step_type=0,0,2 ctrl_type=p,p,v

will install three step generators. The ﬁrst two use step type ’0’ (step and direction) and run in position mode. The last one uses step type ’2’ (quadrature) and runs in velocity mode. The default value for <config-array> is “0,0,0” which will install three type ’0’ (step/dir) generators. The maximum number of step generators is 8 (as deﬁned by MAX_CHAN in stepgen.c). Each generator is independent, but all are updated by the same function(s) at the same time. In the following descriptions, <chan> is the number of a speciﬁc generator. The ﬁrst generator is number 0.

8.4.2 Removing

emc2$ halcmd unloadrt stepgen

8.4.3 Pins

Each step pulse generator will have only some of these pins, depending on the step type and control type selected.

• (F L O A T) stepgen.<chan>.position-cmd – Desired motor position, in position units (position mode only).

• (F L O A T) stepgen.<chan>.velocity-cmd – Desired motor velocity, in position units per second (velocity mode only).

• (S32) stepgen.<chan>.counts – Feedback position in counts, updated by capture_position().

• (F L O A T) stepgen.<chan>.position-fb – Feedback position in position units, updated by

capture_position().

• (B I T) stepgen.<chan>.enable – Enables output steps - when false, no steps are generated.

• (B I T) stepgen.<chan>.step – Step pulse output (step type 0 only).

• (B I T) stepgen.<chan>.dir – Direction output (step type 0 only).

• (B I T) stepgen.<chan>.up – UP pseudo-PWM output (step type 1 only).

• (B I T) stepgen.<chan>.down – DOWN pseudo-PWM output (step type 1 only).

• (B I T) stepgen.<chan>.phase-A – Phase A output (step types 2-14 only).

• (B I T) stepgen.<chan>.phase-B – Phase B output (step types 2-14 only).

• (B I T) stepgen.<chan>.phase-C – Phase C output (step types 3-14 only).

• (B I T) stepgen.<chan>.phase-D – Phase D output (step types 5-14 only).

• (B I T) stepgen.<chan>.phase-E – Phase E output (step types 11-14 only).

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8.4.4 Parameters

• (F L O A T) stepgen.<chan>.position-scale – Steps per position unit. This parameter is used for both output and feedback.

• (F L O A T) stepgen.<chan>.maxvel – Maximum velocity, in position units per second. If 0.0, has no effect.

• (F L O A T) stepgen.<chan>.maxaccel – Maximum accel/decel rate, in positions units per second squared. If 0.0, has no effect.

• (F L O A T) stepgen.<chan>.frequency – The current step rate, in steps per second.

• (F L O A T) stepgen.<chan>.steplen – Length of a step pulse (step type 0 and 1) or minimum

time in a given state (step types 2-14), in nano-seconds.

• (F L O A T) stepgen.<chan>.stepspace – Minimum spacing between two step pulses (step types 0 and 1 only), in nano-seconds.

• (F L O A T) stepgen.<chan>.dirsetup – Minimum time from a direction change to the beginning of the next step pulse (step type 0 only), in nanoseconds.

• (F L O A T) stepgen.<chan>.dirhold – Minmum time from the end of a step pulse to a direction change (step type 0 only), in nanoseconds.

• (F L O A T) stepgen.<chan>.dirdelay – Minmum time any step to a step in the opposite direction (step types 1-14 only), in nano-seconds.

• (S32) stepgen.<chan>.rawcounts – The raw feedback count, updated by make_pulses().

In position mode, the values of maxvel and maxaccel are used by the internal position loop to avoid generating step pulse trains that the motor cannot follow. When set to values that are appropriate for the motor, even a large instantaneous change in commanded position will result in a smooth trapezoidal move to the new location. The algorithm works by measuring both position error and velocity error, and calculating an acceleration that attempts to reduce both to zero at the same time. For more details, including the contents of the “control equation” box, consult the code.

In velocity mode, maxvel is a simple limit that is applied to the commanded velocity, and maxaccel is used to ramp the actual frequency if the commanded velocity changes abruptly. As in position mode, proper values for these parameters ensure that the motor can follow the generated pulse train.

8.4.5 Step Types

The step generator supports 15 different “step types”. Step type 0 is the most familiar, standard step and direction. When conﬁgured for step type 0, there are four extra parameters that determine the exact timing of the step and direction signals. See ﬁgure 8.4 for the meaning of these parameters. The parameters are in nanoseconds, but will be rounded up to an integer multiple of the thread period for the threaed that calls make_pulses(). For example, if make_pulses() is called every 16uS, and steplen is 20000, then the step pulses will be 2 x 16 = 32uS long. The default value for all four of the parameters is 1nS, but the automatic rounding takes effect the ﬁrst time the code runs. Since one step requires steplen nS high and stepspace nS low, the maximum frequency is 1,000,000,000 divided by (steplen+stepspace). If maxfreq is set higher than that limit, it will be lowered automatically. If maxfreq is zero, it will remain zero, but the output frequency will still be limited.

Step type 1 has two outputs, up and down. Pulses appear on one or the other, depending on the direction of travel. Each pulse is steplen nS long, and the pulses are separated by at least stepspace nS. The maximum frequency is the same as for step type 0. If maxfreq is set higher

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steplen

stepspace

(min)

stepspace

(min)

dirsetup

(min)

dirsetup

(min)

dirhold

(min)

steplen

step

direction

Figure 8.4: Step and Direction Timing

than the limit it will be lowered. If maxfreq is zero, it will remain zero but the output frequency will still be limited.

Step types 2 through 14 are state based, and have from two to ﬁve outputs. On each step, a state counter is incremented or decremented. Figures 8.5, 8.6, and 8.7 show the output patterns as a function of the state counter. The maximum frequency is 1,000,000,000 divided by steplen, and as in the other modes, maxfreq will be lowered if it is above the limit.

8.4.6 Functions

The component exports three functions. Each function acts on all of the step pulse generators running different generators in different threads is not supported.

• (F U N C T) stepgen.make-pulses – High speed function to generate and count pulses (no ﬂoating point).

• (F U N C T) stepgen.update-freq – Low speed function does position to velocity conversion, scaling and limiting.

• (F U N C T) stepgen.capture-position – Low speed function for feedback, updates latches and scales position.

The high speed function stepgen.make-pulses should be run in a very fast thread, from 10 to 50uS depending on the capabilities of the computer. That thread’s period determines the maximum step frequency, since steplen, stepspace, dirsetup, dirhold, and dirdelay are all rounded up to a integer multiple of the thread periond in nanoseconds. The other two functions can be called at a much lower rate.

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00011122214003325100211322003

STEP TYPE 3

STEP TYPE 4

STEP TYPE 2

phase-A

phase-B

phase-C

Figure 8.5: Three-Phase step types

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000

0011111122222200004433333311115522226633337700000

0 STEP TYPE 5

STEP TYPE 6

STEP TYPE 7

STEP TYPE 8

STEP TYPE 9

STEP TYPE 10

phase-A

phase-B

phase-C

phase-D

Figure 8.6: Four-Phase Step Types

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00000011111122222244444433333355667788990000STEP TYPE 11

STEP TYPE 12

STEP TYPE 14

STEP TYPE 13

phase-A

phase-B

phase-C

phase-D

phase-E

Figure 8.7: Five-Phase Step Types

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8.5 PWMgen

This component provides software based generation of PWM (Pulse Width Modulation) and PDM (Pulse Density Modulation) waveforms. It is a realtime component only, and depending on CPU speed, etc, is capable of PWM frequencies from a few hundred Hertz at pretty good resolution, to perhaps 10KHz with limited resolution.

8.5.1 Installing

emc2$ halcmd loadrt pwmgen output_type=<config-array>

<config-array> is a series of comma separated decimal integers. Each number causes a single

PWM generator to be loaded, the value of the number determines the output type. For example:

emc2$ halcmd loadrt pwmgen output_type=0,1,2

will install three PWM generators. The ﬁrst one will use output type ’0’ (PWM only), the next uses output type 1 (PWM and direction) and the last one uses output type 2 (UP and DOWN). There is no default value, if <config-array> is not speciﬁed, no PWM generators will be installed. The maximum number of frequency generators is 8 (as deﬁned by MAX_CHAN in pwmgen.c). Each generator is independent, but all are updated by the same function(s) at the same time. In the following descriptions, <chan> is the number of a speciﬁc generator. The ﬁrst generator is number

8.5.2 Removing

emc2$ halcmd unloadrt pwmgen

8.5.3 Pins

Each PWM generator will have the following pins:

• (F L O A T) pwmgen.<chan>.value – Command value, in arbitrary units. Will be scaled by the scale parameter (see below).

• (B I T) pwmgen.<chan>.enable – Enables or disables the PWM generator outputs.

Each PWM generator will also have some of these pins, depending on the output type selected:

• (B I T) pwmgen.<chan>.pwm – PWM (or PDM) output, (output types 0 and 1 only).

• (B I T) pwmgen.<chan>.dir – Direction output (output type 1 only).

• (B I T) pwmgen.<chan>.up – PWM/PDM output for positive input value (output type 2 only).

• (B I T) pwmgen.<chan>.down – PWM/PDM output for negative input value (output type 2 only).

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8.5.4 Parameters

• (F L O A T) pwmgen.<chan>.scale – Scaling factor to convert value from arbitrary units to duty cycle.

• (F L O A T) pwmgen.<chan>.pwm-freq – Desired PWM frequency, in Hz. If 0.0, generates PDM instead of PWM. If set higher than internal limits, next call of update_freq() will set it to the internal limit. If non-zero, and dither is false, next call of update_freq() will set it to the nearest integer multiple of the make_pulses() function period.

• (B I T) pwmgen.<chan>.dither-pwm – If true, enables dithering to achieve average PWM frequencies or duty cycles that are unobtainable with pure PWM. If false, both the PWM frequency and the duty cycle will be rounded to values that can be achieved exactly.

• (F L O A T) pwmgen.<chan>.min-dc – Minimum duty cycle, between 0.0 and 1.0 (duty cycle will go to zero when disabled, regardless of this setting).

• (F L O A T) pwmgen.<chan>.max-dc – Maximum duty cycle, between 0.0 and 1.0.

• (F L O A T) pwmgen.<chan>.curr-dc – Current duty cycle - after all limiting and rounding (read

only).

8.5.5 Output Types

The PWM generator supports three different “output types”. Type 0 has a single output pin. Only positive commands are accepted, negative values are treated as zero (and will be affected by min-dc if it is non-zero). Type 1 has two output pins, one for the PWM/PDM signal and one to indicate direction. The duty cycle on the PWM pin is based on the absolute value of the command, so negative values are acceptable. The direction pin is false for positive commands, and true for negative commands. Finally, type 2 also has two outputs, called up and down. For positive commands, the PWM signal appears on the up output, and the down output remains false. For negative commands, the PWM signal appears on the down output, and the up output remains false. Output type 2 is suitable for driving most H-bridges.

8.5.6 Functions

The component exports two functions. Each function acts on all of the PWM generators - running different generators in different threads is not supported.

• (F U N C T) pwmgen.make-pulses – High speed function to generate PWM waveforms (no ﬂoating point).

• (F U N C T) pwmgen.update – Low speed function to scale and limit value and handle other paremeters.

The high speed function pwmgen.make-pulses should be run in a very fast thread, from 10 to 50uS depending on the capabilities of the computer. That thread’s period determines the maximum PWM carrier frequency, as well as the resolution of the PWM or PDM signals. The other function can be called at a much lower rate.

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reset

index-enable

phase-Z

phase-B

phase-A

counts

position

latch

counter

edge

detect

quad

decode

rawcounts

position-scale

up/dn

count

clear

update-counters()

capture-position()

encoder.0

8.6 Encoder

This component provides software based counting of signals from quadrature encoders. It is a realtime component only, and depending on CPU speed, latency, etc, is capable of maximum count rates of 10kHz to perhaps up to 50kHz. Figure 8.8 is a block diagram of one channel of encoder counter.

Figure 8.8: Encoder Counter Block Diagram

8.6.1 Installing

emc2$ halcmd loadrt encoder [num_chan=<counters>]

<counters> is the number of encoder counters that you want to install. If numchan is not speciﬁed,

three counters will be installed. The maximum number of counters is 8 (as deﬁned by MAX_CHAN in encoder.c). Each counter is independent, but all are updated by the same function(s) at the same time. In the following descriptions, <chan> is the number of a speciﬁc counter. The ﬁrst counter is number 0.

8.6.2 Removing

emc2$ halcmd unloadrt encoder

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8.6.3 Pins

• encoder.<chan>.counter-mode (bit, I/O) (default: FALSE) – Enables counter mode. When true, the counter counts each rising edge of the phase-A input, ignoring the value on phase-B. This is useful for counting the output of a single channel (non-quadrature) sensor. When false, it counts in quadrature mode.

• encoder.<chan>.counts (s32, Out) – Position in encoder counts.

• encoder.<chan>.counts-latched (s32, Out) – Not used at this time.

• encoder.<chan>.index-enable (bit, I/O) – When True, counts and position are reset to

zero on next rising edge of Phase Z. At the same time, index-enable is reset to zero to indicate that the rising edge has occoured. The index-enable pin is bi-directional. If index-enable is False, the Phase Z channel of the encoder will be ignored, and the counter will count normally. The encoder driver will never set index-enable True. However, some other component may do so.

• encoder.<chan>.latch-falling (bit, In) (default: TRUE) – Not used at this time.

• encoder.<chan>.latch-input (bit, In) (default: TRUE) – Not used at this time.

• encoder.<chan>.latch-rising (bit, In) – Not used at this time.

• encoder.<chan>.min-speed-estimate (ﬂoat, in) – Determine the minimum true velocity

magnitude at which velocity will be estimated as nonzero and postition-interpolated will be interpolated. The units of min-speed-estimate are the same as the units of velocity. Scale factor, in counts per length unit. Setting this parameter too low will cause it to take a long time for velocity to go to 0 after encoder pulses have stopped arriving.

• encoder.<chan>.phase-A (bit, In) – Phase A of the quadrature encoder signal.

• encoder.<chan>.phase-B (bit, In) – Phase B of the quadrature encoder signal.

• encoder.<chan>.phase-Z (bit, In) – Phase Z (index pulse) of the quadrature encoder signal.

• encoder.<chan>.position (ﬂoat, Out) – Position in scaled units (see position-scale).

• encoder.<chan>.position-interpolated (ﬂoat, Out) – Position in scaled units, interpolated

between encoder counts. The position-interpolated attempts to interpolate between encoder counts, based on the most recently measured velocity. Only valid when velocity is approximately constant and above min-speed-estimate. Do not be used for position control, since its value is incorrect at low speeds, during direction reversals, and during speed changes. However, it allows a low ppr encoder (including a one pulse per revolution "encoder") to be used for lathe threading, and may have other uses as well.

• encoder.<chan>.position-latched (float, Out) – Not used at this time.

• encoder.<chan>.position-scale (float, I/O) – Scale factor, in counts per length unit.

For example, if position-scale is 500, then 1000 counts of the encoder will be reported as a position of 2.0 units.

• encoder.<chan>.rawcounts (s32, In) – The raw count, as determined by update-counters. This value is updated more frequently than counts and position. It is also unaffected by reset or the index pulse.

• encoder.<chan>.reset (bit, In) – When True, force counts and position to zero immedi- ately.

• encoder.<chan>.velocity (ﬂoat, Out) – Velocity in scaled units per second. encoder uses an algorithm that greatly reduces quantization noise as compared to simply differentiating the position output. When the magnitude of the true velocity is below min-velocity-estimate, the velocity output is 0.

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• encoder.<chan>.x4-mode (bit, I/O) (default: TRUE) – Enables times-4 mode. When true, the counter counts each edge of the quadrature waveform (four counts per full cycle). When false, it only counts once per full cycle. In counter-mode, this parameter is ignored. The 1x mode is usefull for some jogwheels.

8.6.4 Parameters

• encoder.<chan>.capture-position.time (s32, RO)

• encoder.<chan>.capture-position.tmax (s32, RW)

• encoder.<chan>.update-counters.time (s32, RO)

• encoder.<chan>.update-counter.tmax (s32, RW)

8.6.5 Functions

The component exports two functions. Each function acts on all of the encoder counters - running different counters in different threads is not supported.

• (F U N C T) encoder.update-counters – High speed function to count pulses (no ﬂoating point).

• (F U N C T) encoder.capture-position – Low speed function to update latches and scale po-

sition.

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8.7 PID

This component provides Proportional/Integeral/Derivative control loops. It is a realtime component only. For simplicity, this discussion assumes that we are talking about position loops, however this component can be used to implement other feedback loops such as speed, torch height, temperature, etc. Figure 8.9 is a block diagram of a single PID loop.

8.7.1 Installing

emc2$ halcmd loadrt pid [num_chan=<loops>] [debug=1]

<loops> is the number of PID loops that you want to install. If numchan is not speciﬁed, one loop

will be installed. The maximum number of loops is 16 (as deﬁned by MAX_CHAN in pid.c). Each loop is completely independent. In the following descriptions, <loopnum> is the loop number of a speciﬁc loop. The ﬁrst loop is number 0.

If debug=1 is speciﬁed, the component will export a few extra parameters that may be useful during debugging and tuning. By default, the extra parameters are not exported, to save shared memory space and avoid cluttering the parameter list.

8.7.2 Removing

emc2$ halcmd unloadrt pid

8.7.3 Pins

The three most important pins are

• (F L O A T) pid.<loopnum>.command – The desired position, as commanded by another system component.

• (F L O A T) pid.<loopnum>.feedback – The present position, as measured by a feedback device such as an encoder.

• (F L O A T) pid.<loopnum>.output – A velocity command that attempts to move from the present position to the desired position.

For a position loop, ’command’ and ’feedback’ are in position units. For a linear axis, this could be inches, mm, meters, or whatever is relevant. Likewise, for an angular axis, it could be degrees, radians, etc. The units of the ’output’ pin represent the change needed to make the feedback match the command. As such, for a position loop ’Output’ is a velocity, in inches/sec, mm/sec, degrees/sec, etc. Time units are always seconds, and the velocity units match the position units. If command and feedback are in meters, then output is in meters per second.

Each loop has two pins which are used to monitor or control the general operation of the component.

• (F L O A T) pid.<loopnum>.error – Equals .command minus .feedback.

• (B I T) pid.<loopnum>.enable – A bit that enables the loop. If .enable is false, all integrators

are reset, and the output is forced to zero. If .enable is true, the loop operates normally.

Pins used to report saturation. Saturation occurs when the output of the PID block is at its maximum or minimum limit.

• (B I T) pid.<loopnum>.saturated – True when output is saturated.

• (F L O A T) pid.<loopnum>.saturated_s – The time the output has been saturated.

• (S32) pid.<loopnum>.saturated_count – The time the output has been saturated.

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EMC V2.4 Integrator Manual Chapter 8. HAL Components

output

enable

command

feedback

error

max-cmdDD

max-cmdD

max-errorD

Pgain

FF2

bias

FF0

FF1

Dgain

Igain

max-errorI

max-output

max-error

deadband

pid.0

ddddTdT

Figure 8.9: PID Loop Block Diagram

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EMC V2.4 Integrator Manual Chapter 8. HAL Components

8.7.4 Parameters

The PID gains, limits, and other ’tunable’ features of the loop are implemented as parameters.

• (F L O A T) pid.<loopnum>.Pgain – Proportional gain

• (F L O A T) pid.<loopnum>.Igain – Integral gain

• (F L O A T) pid.<loopnum>.Dgain – Derivative gain

• (F L O A T) pid.<loopnum>.bias – Constant offset on output

• (F L O A T) pid.<loopnum>.FF0 – Zeroth order feedforward - output proportional to command

(position).

• (F L O A T) pid.<loopnum>.FF1 – First order feedforward - output proportional to derivative of command (velocity).

• (F L O A T) pid.<loopnum>.FF2 – Second order feedforward - output proportional to 2nd derivative of command (acceleration)1.

• (F L O A T) pid.<loopnum>.deadband – Amount of error that will be ignored

• (F L O A T) pid.<loopnum>.maxerror – Limit on error

• (F L O A T) pid.<loopnum>.maxerrorI – Limit on error integrator

• (F L O A T) pid.<loopnum>.maxerrorD – Limit on error derivative

• (F L O A T) pid.<loopnum>.maxcmdD – Limit on command derivative

• (F L O A T) pid.<loopnum>.maxcmdDD – Limit on command 2nd derivative

• (F L O A T) pid.<loopnum>.maxoutput – Limit on output value

All of the max??? limits are implemented such that if the parameter value is zero, there is no limit.

If debug=1 was speciﬁed when the component was installed, four additional parameters will be exported:

• (F L O A T) pid.<loopnum>.errorI – Integral of error.

• (F L O A T) pid.<loopnum>.errorD – Derivative of error.

• (F L O A T) pid.<loopnum>.commandD – Derivative of the command.

• (F L O A T) pid.<loopnum>.commandDD – 2nd derivative of the command.

8.7.5 Functions

The component exports one function for each PID loop. This function performs all the calculations needed for the loop. Since each loop has its own function, individual loops can be included in different threads and execute at different rates.

• (F U N C T) pid.<loopnum>.do_pid_calcs – Performs all calculations for a single PID loop.

If you want to understand the exact algorithm used to compute the output of the PID loop, refer to ﬁgure 8.9, the comments at the beginning of emc2/src/hal/components/pid.c, and of course to the code itself. The loop calculations are in the C function calc_pid().

FF2 is not currently implemented, but it will be added. Consider this note a “FIXME” for the code

linuxcnc EMC2 Users Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

Important Concepts

1.1 Stepper Systems

1.1.1 Base Period

1.1.2 Step Timing

1.2 Servos

1.2.1 Tuning

1.2.2 Proportional term

1.2.3 Integral term

1.2.4 Derivative term

1.2.5 Loop tuning

1.2.6 Manual tuning

1.3 RTAI

Hardware

2.1 Latency Test

2.2 Port Address

INI File

4.1 The INI File Layout

4.1.1 Comments

4.1.2 Sections

4.1.3 Variables

4.2 Sections

4.2.1 [EMC] Section

4.2.2 [DISPLAY] Section

4.2.3 [FILTER] Section

4.2.4 [RS274NGC] Section

4.2.5 [EMCMOT] Section

4.2.6 [TASK] Section

4.2.7 [HAL] section

4.2.8 [TRAJ] Section

4.2.9 [AXIS_<num>] Section

4.2.10 [EMCIO] Section

4.3 Homing

4.3.1 Overview

4.3.2 Homing Sequence

4.4 Lathe

4.4.1 Default Plane

4.4.2 INI Settings

EMC2 and HAL

5.1 motion (realtime)

5.1.1 Options

5.1.2 Pins

5.1.3 Parameters

5.1.4 Functions

5.2 axis.N (realtime)

5.2.1 Pins

5.2.2 Parameters

5.3 iocontrol (userspace)

5.3.1 Pins

Getting Started

6.1 Hal Commands

6.1.1 loadrt

6.1.2 addf

6.1.3 loadusr

6.1.5 setp

6.1.6 unlinkp

6.1.7 Obsolete Commands

6.2 Hal Data

6.2.2 Float

6.3 Hal Files

6.4 HAL Components

6.5 Logic Components

6.5.1 and2

6.5.4 xor2

6.5.5 Logic Examples

6.6 Conversion Components

6.6.1 weighted_sum

6.7 Halshow

6.7.1 Starting Halshow

6.7.2 Hal Tree Area

6.7.3 Hal Show Area

6.7.4 Hal Watch Area

7.1 Introduction

7.2 Maximum step rate

7.3 Pinout

7.3.1 standard_pinout.hal

7.3.2 Overview of the standard_pinout.hal