7I48 MANUAL
Six channel analog servo amp interface
V1.6
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Table of Contents
GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
HARDWARE CONFIGURATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
DEFAULT JUMPER LOCATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
TTL/RS-422 ENCODER SELECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
CABLE POWER/P1 POWER SELECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
CONNECTORS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
CONNECTOR LOCATIONS AND DEFAULT JUMPERS . . . . . . . . . . . . . . . . . 3
CONTROLLER CONNECTOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
AUX 5V POWER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
SERVO AMP/ENCODER CONNECTORS . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
PWM RATE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
STEP RESPONSE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
ENCODER INPUT CIRCUIT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
MAXIMUM COUNT RATE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
5V POWER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
ENABLE INPUTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
ENABLE OUTPUTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
ANALOG OUTPUTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
DRAWINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
7I48 1
GENERAL
DESCRIPTION
The 7I48 is a 6 axis analog servo interfaces intended for operation with MESA’s
Anything I/O cards when used for motion control applications. The 7I48 uses encoder
multiplexing to allow a single Anything-I/O connector to support a six axis interface.
The 7I48 takes up/down PWM or PDM signals from the Anything I/O card and
converts them to +- 10V analog output voltages for direct connection to analog input servo
amplifiers. The 7I48 models also conditions and multiplexes the encoder input signals with
input buffers for TTL inputs a RS-422 receivers for differential encoder inputs.
The controller connection is a 50 pin header that matches the pinout of the Mesa
anything I/O series of cards. The 7I48 uses Phoenix compatible 3.5 mm headers and is
supplied with pluggable terminal blocks.
7I48 2
HARDWARE CONFIGURATION
GENERAL
Hardware setup jumper positions assume that the 7I48 card is oriented in an upright
position, that is, with the 50 pin controller connector is on the left hand side,
DEFAULT CONFIGURATION
JUMPER FUNCTION DEFAULT SETTING
W1 CABLE POWER SELECT RIGHT = CABLE POWER
W13,W16,W19 CH0 TTL/RS-422 SELECT LEFT = TTL
W4,W7,W10 CH1 TTL/RS-422 SELECT LEFT = TTL
W12,W15,W18 CH2 TTL/RS-422 SELECT LEFT = TTL
W3,W6,W9 CH3 TTL/RS-422 SELECT LEFT = TTL
W11,W14,W17 CH4 TTL/RS-422 SELECT LEFT = TTL
W2,W5,W8 CH5 TTL/RS-422 SELECT LEFT = TTL
TTL/RS-422 ENCODER SELECTION
Each 7I48 channel has a selectable TTL or RS-422 (differential) encoder input
conditioning. Conditioning type is determined by setting groups of 3 jumpers to the left or
right position. When the jumpers are in the "LEFT" position, TTL inputs are selected, When
the jumpers are in the "RIGHT" position, RS-422 inputs are selected. Note these sets of
three jumpers are in physical proximity to the terminal block encoder connections.
CABLE POWER/P1 POWER SELECTION
The 7I48 can get its operating power from the flat FPGA cable or from P1. For
testing and with very low power encoders, cable power can be used. W1 selects whether
cable power connects to the 7I48s 5V supply. If W1 is in the "RIGHT" position, cable
power is selected. If W1 is in the "LEFT" position, external 5V power must be supplied via
P1.
7I48 3
CONNECTORS
CONNECTOR LOCATIONS AND DEFAULT JUMPER POSITIONS
7I48 4
CONNECTORS
CONTROLLER CONNECTOR
50 pin header connector J1 connects to the anything I/O card/motion controller. This
can be a male 50 pin header on the top of the 7I48 card or a female 50 conductor header
on the bottom side of the 7I48 depending on 7I48 model. Controller connector pin-out is
as follows:
PIN FUNCTION DIRECTION PIN FUNCTION DIRECTION
1 /ENA0 TO 7I48 25 PWM-0 TO 7I48
3 MUXQA0 FROM 7I48 27 PWM+1 TO 7I48
5 MUXQB0 FROM 7I48 29 PWM-1 TO 7I48
7 MUXIDX0 FROM 7I48 31 PWM+2 TO 7I48
9 MUXQA1 FROM 7I48 33 PWM-2 TO 7I48
11 MUXQB1 FROM 7I48 35 PWM+3 TO 7I48
13 MUXIDX1 FROM 7I48 37 PWM-3 TO 7I48
15 MUXQA2 FROM 7I48 39 PWM+4 TO 7I48
17 MUXQB2 FROM 7I48 41 PWM-4 TO 7I48
19 MUXIDX2 FROM 7I48 43 PWM+5 TO 7I48
21 MUXSEL0 TO 7I48 45 PWM-5 TO 7I48
23 PWM+0 TO 7I48 47 /ENA1 TO 7I48
49 +5V PWR TO 7I48
Note: all even pins are grounded.
AUX 5V POWER
The 7I48 can get its 5V power from the FPGA cable or connector P1. Normally P1
should be used for power as the 5V current draw from 6 encoders will exceed what the
FPGA flat cable can deliver. Note that the 7I48 will only connect to P1 power if the cable
5V is present.
PIN FUNCTION
1 5V
2 GND
7I48 5
CONNECTORS
SERVO AMP/ENCODER CONNECTORS
The 7I48's servo amplifier / encoder connectors (P2,P3, and P4 ) are 3.5MM 24 pin
headers compatible with Phoenix style screw terminal blocks (supplied). Connector P4 has
the I/O signals for channels 0 and 1:
P4 PIN FUNCTION DIR
1 ENCA0 TO 7I48
2 /ENCA0 TO 7I48
3 GND FROM 7I48
4 ENCB0 TO 7I48
5 /ENCB0 TO 7I48
6 +5V FROM 7I48
7 IDX0 TO 7I48
8 /IDX0 TO 7I48
9 ENCA1 TO 7I48
10 /ENCA1 TO 7I48
11 GND FROM 7I48
12 ENCB1 TO 7I48
13 /ENCB1 TO 7I48
14 +5V FROM 7I48
15 IDX1 TO 7I48
16 /IDX1 TO 7I48
17 ENA0- FROM 7I48
18 ENA0+ FROM 7I48
19 GND0 FROM 7I48
20 AOUT0 FROM 7I48
21 ENA1- FROM 7I48
22 ENA1+ FROM 7I48
23 GND1 FROM 7I48
24 AOUT1 FROM 7I48
7I48 6
CONNECTORS
SERVO AMP/ENCODER CONNECTORS
Connector P3 has the I/O signals for channels 2 and 3:
P3 PIN FUNCTION DIR
1 ENCA2 TO 7I48
2 /ENCA2 TO 7I48
3 GND FROM 7I48
4 ENCB2 TO 7I48
5 /ENCB2 TO 7I48
6 +5V FROM 7I48
7 IDX2 TO 7I48
8 /IDX2 TO 7I48
9 ENCA3 TO 7I48
10 /ENCA3 TO 7I48
11 GND FROM 7I48
12 ENCB3 TO 7I48
13 /ENCB3 TO 7I48
14 +5V FROM 7I48
15 IDX3 TO 7I48
16 /IDX3 TO 7I48
17 ENA2- FROM 7I48
18 ENA2+ FROM 7I48
19 GND2 FROM 7I48
20 AOUT2 FROM 7I48
21 ENA3- FROM 7I48
22 ENA3+ FROM 7I48
23 GND3 FROM 7I48
24 AOUT3 FROM 7I48
7I48 7
CONNECTORS
SERVO AMP/ENCODER CONNECTORS
Connector P2 has the I/O signals for channels 4 and 5:
P2 PIN FUNCTION DIR
1 ENCA4 TO 7I48
2 /ENCA4 TO 7I48
3 GND FROM 7I48
4 ENCB4 TO 7I48
5 /ENCB4 TO 7I48
6 +5V FROM 7I48
7 IDX4 TO 7I48
8 /IDX4 TO 7I48
9 ENCA5 TO 7I48
10 /ENCA5 TO 7I48
11 GND FROM 7I48
12 ENCB5 TO 7I48
13 /ENCB5 TO 7I48
14 +5V FROM 7I48
15 IDX5 TO 7I48
16 /IDX5 TO 7I48
17 ENA4- FROM 7I48
18 ENA4+ FROM 7I48
19 GND4 FROM 7I48
20 AOUT4 FROM 7I48
21 ENA5- FROM 7I48
22 ENA5+ FROM 7I48
23 GND5 FROM 7I48
24 AOUT5 FROM 7I48
7I48 8
OPERATION
PWM RATE
The 7I48 is meant to operate with PWM rates from 24 KHz to 500 KHz. Operation
at lower PWM rates will result in excessive output ripple, operation at higher PWM rates
or with PDM with higher than 10 MHz base frequency will result in poor linearity. When
used with HostMot2 firmware, the PWM generators should be set for UP/DOWN mode
(mode 2) and the PWM frequency set for 24 KHz.
STEP RESPONSE
The 7I48 has a 5 pole PWM filter with an approximate 150 uSec time constant. This
value is selected as a compromise between output ripple and settling time. This is much
faster than most controlled devices and will not normally have any effect on loop stability
or performance. The 7I48 can be assembled with different components if necessary to
change this time constant.
ENCODER INPUT CIRCUIT
The 7I48 input circuit is different depending on whether TTL or RS-422 encoder
types have been selected. In TTL mode the input circuit on the encoder A,B, and index
inputs drive one input of the RS-422 differential receiver, and the other receiver input is
terminated to a 1.6V (TTL threshold) reference voltage. In RS-422 mode, the input consists
of a 132 Ohm termination resistor and a 26LS32 RS-422 differential receiver.
When TTL encoders are used, they connect to the ‘True’ input of the differential
pair, for example a TTL encoder for channel 2 would connect to ENCA2, ENCB2 and IDX2,
while the /ENCA2,/ENCB2, and /IDX2 terminals would be left open.
Fine print: normally the input mode jumpers would always be moved as a sets of
three to select TTL or RS-422 mode for individual encoders, however it is possible to
select TTL or RS-422 mode for each encoder signal, for example if a encoder had a
differential A,B but TTL index, the input circuit can accommodate this. The three input
mode select jumpers are in bottom to top order: A,B,INDEX.
MAXIMUM COUNT RATE
The 7I48 uses multiplexed encoder signals to save interface pins. The multiplexing
rate will determine the maximum encoder count rate. Default multiplexing rate with
HostMot2 firmware is ClockLow / 8, or approximately 4 or 6 MHz, giving a resolvable count
rate of 2 to 3 MHz. Multiplexing rate can be increased if desired but high multiplex rates
will require short cables between the FPGA controller card and the 7I48 due to signal
integrity and time-of-flight considerations. Maximum practical multiplex rate is
approximately 12 MHz (and 6 MHz count rates). Encoder count rate is further limited by
HostMot2s input filtering to ~5 to ~8 million counts per second (encoder filtering off) and
~1 to ~1.6 million counts per second (encoder filtering on).
7I48 9
OPERATION
5V POWER
The 7I48 requires ~400 mA of 5V power for operation. Encoder power can also be
supplied from the 7I48's 5V source. Power for the 7I48 is normally supplied from P1 but
can also be supplied via pin 49 of the 50 conductor controller cable when testing or when
low power encoders are used.
ENABLE INPUTS
There are two active low enable inputs on the 7I48 from the FPGA card. When
either of these enable inputs is high, all AOUTs are forced to 0V, and all enable outputs
are turned off. Pullup resistors keep the enable inputs high if the controller connection is
lost.
ENABLE OUTPUTS
Each 7I48 channel has a OPTO-isolated transistor output that can be used to
enable external amplifiers. All six outputs are on when both input enable signals are low,
that is all enable outputs are switched at once. Maximum switched voltage is 36VDC.
Maximum output current is 10 mA. Even though all outputs are switched in common, they
are all isolated to allow different enable connections on a per amplifier basis.
Example connections:
1. Active high 12V amplifier enable on ch 0:
Connect ENA0+ to +12V source
Connect ENA0- to amplifier enable input
2. Active low TTL input
Connect ENA2- to ground
Connect ENA2+ to amplifier enable input
ANALOG OUTPUTS
The analog output of the 7I48 swings from -10 v to +10V. Positive outputs are
generated when PWM+ is input is driven, and negative outputs when PWM- is driven. A
50 % duty cycle PWM signal will generate a 5V output. This mode of operation require the
PWM generator be set for "up/down" mode. Due to power supply limitations, The 7I48 has
limited DC output drive capability and should not have loads of less than 3K Ohms on its
analog outputs. (~24 mA maximum total +-10v current). To avoid power supply damage,
do no short more than one analog output at once.
7I48 10
SPECIFICATIONS
MIN MAX UNITS
5V POWER SUPPLY 4.75 5.25 VDC
5V POWER CONSUMPTION --- 500 mA
(no external load)
ANALOG OUTPUT VOLTAGE +-9.8 +-10.2 V
ANALOG OUTPUT STEP RESPONSE 120 160 uSec
MINIMUM AOUT LOAD RESISTANCE 3K --- Ohm
OUTPUT RIPPLE @ 24 KHZ PWM --- .1% % FS
LINEARITY --- .1% % FS
(no missing codes, 13 bit resolution with 24 KHz PWM)
ZERO OFFSET ERROR -10 +10 mV
ENCODER FREQUENCY DC 4 MHz
(8 MHz multiplex frequency selected)
OPERATING TEMP. 0 +70
o
C
OPERATING TEMP. (-I version) -40 +85
o
C
OPERATION HUMIDITY 0 95% NON-COND
7I48 11
DRAWINGS
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