BECKHOFF M3120 User Manual

M3120 Incremental encoder 4x Beckhoff II/O-Lightbus

M3120

Incremental encoder

4 x

Technical description

Eiserstraße 5 phone [phone]
D-33415 Verl fax [phone]

Date 20.10.94 Version 1.1 Page 1 of 14

M3120 Incremental encoder 4x Beckhoff II/O-Lightbus

Table of vontents

1. Function description hardware ........................................................................3

2. Function description software ..........................................................................5

3. Technical data....................................................................................................8

4. Installation........................................................................................................10

5. Connection table ..............................................................................................12

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M3120 Incremental encoder 4x Beckhoff II/O-Lightbus

1. Function description hardware

M3120

The periphery module M3120 establishes the connection of four incremental encoders for the
II/O-Lightbus system. It contains three separate power supplies for logic (5V) and pick off
power supply (5/15V) and the level adjustment from 15 V down to 5V. 5 V or 15 V encoder
can be connected to the incremental box M3120, either with or without complementary
channels.

All digital functions are integrated in four separate periphery controller (LCA circuit):

- 24 bit UP/DOWN counter with a limiting frequency of 1.25 MHz.

- Input "counter disable"

- 24 bit latch for counter position at zero impulse.

- Squareness decoder with adjustable 1, 2 or 4 times evaluation

- Selective computation of complementary signals (fewer interferences)

- Connection to the II/O-Lightbus with all functions:
addressing, interrupt, address counting, decrease transmission intensity,

cycle and error LED

- Read, set and activate commands for counter and zero impulse register via fibre

optic II/O-Lightbus

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M3120 Incremental encoder 4x Beckhoff II/O-Lightbus

Basic circuit diagram

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M3120 Incremental encoder 4x Beckhoff II/O-Lightbus

2. Function description software

Counter functions

- The counter commands are sent in data byte D0 to the module M3120.

- In the data byte D0 the counter status byte is received .

- the counter command byte can only be written

- the counter status byte can only be read.

Counter command byte

In order to transmit commands to the module M3120, the following bits of the counter
command byte can be set and then written to the data byte D0 of an II/O-Lightbus telegram.

76563210

* * * * EL SC RL RC

Bit Value Signal Function

0 RC=1 READ

COUNTER

1 RL=1 READ

LATCH

2SC=1SET

COUNTER

3 EL=1 ENABLE

LATCH

Read 24 bit counter

(D1 = LOW byte, D2 = MID byte, D3 = HIGH byte)

Read 24 bit zero point latch

(D1 = LOW byte, D2 = MID byte, D3 = HIGH byte)
The zero point value (see EL command) is only valid, if the LATCH
VALID bit LV is set in the counter sta tus byte. Only a single read
command can be executed at a time. If in a command byte RC=1 and

RL=1, then no value is read

.

Set counter

The counter is only set, if 0001xxxxb is the value in the control byte
of the II/O telegram.

Activate the zero point latch

the counter is stored in a 24 bit register at the fir st zer o impulse afte r
the EL command was transmitted. Using the RL command the value
can be read many times at any tim e, The LV bit is only dele ted after
the EL command was transmitted. It is only set again, if a zero point
value was stored. The EL com mand is only executed, if 0001xxxx
is the value in the control byte of the II/O telegram.

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M3120 Incremental encoder 4x Beckhoff II/O-Lightbus

Bit Value Signal Function

4 - - not used
5 - - not used
6 - - not used
7 - - not used

Rem.: The READ, SET and ENABLE commands can be transmitted in any form.

Counter status byte

After an II/O-Lightbus read operation the counter status of the M3120 points to the module in
the data byte DO. The bits of the counter command byte stand for the following functions :

76563210

STAT KOM LV GF2 GF1 GF0 EE1 EE0

Bit Signal Function

0 EE0 Evaluation mode;

must be selectet inside the D- SUB connector by bridges to GND

1 EE1 *)
2GF0
3GF1
4GF2

a low pass filter is adjustable by software
the low pass filter is abjustable to 1250 kHz by hardware

5 LV zero point value valid

LV = 0

The EL command was transmitted, but there was no zero impulse
yet.

LV = 1

the zero point value was latche d

6 KOM COMPLEMENTARY

shows, if a bridge is present in the D-SUB connector

KOM=0

evaluation of normal pick off signals A, B, C; bridge to GND inside
the D-SUB connector

KOM=1

additional evaluation of complementary signals; open, no bridges
inside the D-SUB connector
A, /A, B, /B, C, /C

7 STAT status signal

not in use yet

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M3120 Incremental encoder 4x Beckhoff II/O-Lightbus

*)

Evaluation Mode

EE1 EE0 Evaluation

0 0 1 time
0 1 2 times
1 0 4 times
11 -

Rem.: 0 = GND bridge present

1 = open, no bridge
inside the D-SUB connector ( 15 pins)

II/O-Setup entry

After pasting a module M3120 (incremental encoder 4 times) into the II/O-Lightbus,
following entries have to be made in the II/O-Setup.

Attention: Incremental encoder INC4 must be the fi rst entry and INC1 the fourth entry
in the II/O-Setup Table (look to the example below and to the basic circui t diagram on
page 4):

Example:

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M3120 Incremental encoder 4x Beckhoff II/O-Lightbus

3. Technical data

Pick Off Connection
Pick Off Voltage

Inputs
Input spezification
Input level

Input delay

Counter
Limiting frequency
Squarness decoder

A, A(inv), B, B(inv), C, C(inv),

5 V DC / 15 V DC max 1A, resistable against short
circuit
optional at D-SUB connector

"Counter disable"

24 V DC, 10 mA

0 - 8 V =LOW
15 - 24 V =HIGH

0,1 ms RC filter
Inputs "Counter disable"

24 bit binary

1 MHz

1-2-4 times evaluation

Zero impulse latch
Commands
Data connection
Transmission rate
Power supply
Input current

24 bit

set, read, activate

II/O-Lightbus system

2,5 MBaud, 25µsec for 32 bit

24 V DC (±10%)

0,1 A (without encoder load)

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M3120 Incremental encoder 4x Beckhoff II/O-Lightbus

Housing

Size (W*H*D)
Weight
Operating temperature
Storage temperature
EMI resistance

Vibration resistance

compact aluminium housing
for terminal rail mount

170*76*68 mm

600 g

±0..+55 °C

-20..+70 °C

IEC 801 T4, class 4: 2 kV for signal lines

4 kV for power supply lines

acc. IEC 68-2-29 (vibration and shock)

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M3120 Incremental encoder 4x Beckhoff II/O-Lightbus

4. Installation

The module M3120 is connected to the fibre optic ring using fibre optic connectors (Beckhoff
Z1000). The maximum length of the FO cable, leading to the neighbouring boxes, should not
be more then 600 m for glass fibre or 45 m for other fibres. These values are only valid if for
bending the cable a radius of at least 30 mm is used. If there are no glass fibres used, no
special tools are needed for installation of the plugs.

The module M3120 is installed dezentralized from the machine. Sensors and actors are
connected to the box directly by D-SUB connectors (connector X20, X30, X40, X50).

You can take the power supply for a 5 V or 15 V incremental encoder directly from this
S-SUB connectors.
The LEDs show the status of the module.

Configuration

You can select the times of evaluation over bridges to GND inside the D-SUB connector:

EE1 EE0 evaluation

bridge to
GND
bridge to
GND
open,
no bridge
open,
no bridge

bridge to
GND
open,
no bridge
bridge to
GND
open,
no bridge

1 time
2 times
4 times

-

In case an encoder with single outputs is to be connected, the input "Kom" must be connected
to GND (inside the D-SUB connector X20, X30, X40, X50).

In case an encoder eith complementary outputs is to be connected, the bridge "JP" has to be
removed.

Power supply

A two pin plug in connector is used to establish the 24 V DC power supply. (X10)

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M3120 Incremental encoder 4x Beckhoff II/O-Lightbus

Date 20.10.94 Version 1.1 Page 11 of 14

M3120 Incremental encoder 4x Beckhoff II/O-Lightbus

5. Connection table

Pin assignment

CONNECTOR X10

Connector Pin Signal Description

X10 1 +U
X10 2 -U

CONNECTOR X20

Control voltage +24V
Ground

Connector Pin Signal Description

X20 1 Kom
X20 2 +24V
X20 3 EE1
X20 4 +5V
X20 5 C
X20 6 B/
X20 7 GND
X20 8 A
X20 9 CDI
X20 10 +15V
X20 11 EE0
X20 12 C/
X20 13 GND
X20 14 B
X20 15 A/

Input complementary signals INC1
+24V INC1
Evaluation 1 time, 2 times, 4 times INC1
+5V encoder supply INC1
Channel C INC1
Channel B (inverted) INC1
GND encoder supply INC1
Channel A INC1

Input „Counter disable“ INC1
+15V Encoder supply INC1
Evaluation 1 time, 2 times, 4 times INC1
Channel C (inverted) INC1
GND INC1
Channel B IN C1
Channel A (inverted) INC1

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M3120 Incremental encoder 4x Beckhoff II/O-Lightbus

CONNECTOR X30

Connector Pin Signal Description

X30 1 Kom
X30 2 +24V
X30 3 EE1
X30 4 +5V
X30 5 C
X30 6 B/
X30 7 GND
X30 8 A
X30 9 CDI
X30 10 +15V
X30 11 EE0
X30 12 C/
X30 13 GND
X30 14 B
X30 15 A/

Input complementary signals INC2
+24V INC2
Evaluation 1 time, 2 times, 4 times INC2
+5V encoder supply INC2
Channel C INC2
Channel B (inverted) INC2
GND encoder supply INC2
Channel A INC2

Input „Counter disable“ INC2
+15V Encoder supply INC2
Evaluation 1 time, 2 times, 4 times INC2
Channel C (inverted) INC2
GND INC2
Channel B IN C2
Channel A (inverted) INC2

CONNECTOR X40

Connector Pin Signal Description

X40 1 Kom
X40 2 +24V
X40 3 EE1
X40 4 +5V
X40 5 C
X40 6 B/
X40 7 GND
X40 8 A
X40 9 CDI
X40 10 +15V
X40 11 EE0
X40 12 C/
X40 13 GND
X40 14 B
X40 15 A/

Input complementary signals INC3
+24V INC3
Evaluation 1 time, 2 times, 4 times INC3
+5V encoder supply INC3
Channel C INC3
Channel B (inverted) INC3
GND encoder supply INC3
Channel A INC3
Input „Counter disable“ INC3
+15V Encoder supply INC3
Evaluation 1 time, 2 times, 4 times INC3
Channel C (inverted) INC3
GND INC3
Channel B IN C3
Channel A (inverted) INC3

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M3120 Incremental encoder 4x Beckhoff II/O-Lightbus

CONNECTOR X50

Connector Pin Signal Description

X50 1 Kom
X50 2 +24V
X50 3 EE1
X50 4 +5V
X50 5 C
X50 6 B/
X50 7 GND
X50 8 A
X50 9 CDI
X50 10 +15V
X50 11 EE0
X50 12 C/
X50 13 GND
X50 14 B
X50 15 A/

Input complementary signals INC3
+24V INC3
Evaluation 1 time, 2 times, 4 times INC3
+5V encoder supply INC3
Channel C INC3
Channel B (inverted) INC3
GND encoder supply INC3
Channel A INC3

Input „Counter disable“ INC3
+15V Encoder supply INC3
Evaluation 1 time, 2 times, 4 times INC3
Channel C (inverted) INC3
GND INC3
Channel B IN C3
Channel A (inverted) INC3

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