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CJ1W-SRM21

CJ-series CompoBus/S Master Unit

CJ1W-SRM21

CompoBus/S is a high-speed I/O bus

Communication Specifications

Item Specification
Communications method Special CompoBus/S protocol
Communications baud rate High-speed Communications Mode: 750 kbps
Long-distance Communications Mode: 93.75 kbps
Modulation method Baseband method
Coding method Manchester coding method
Error control checks Manchester code check, frame length check, and parity check
Cable VCTF cable
(JIS C 3306)
Two 0.75 mm2 conductors (2 signal wires)
Four 0.75 mm2 conductors (2 signal wires and 2 power supply wires)
Special Flat
Cable
Four 0.75 mm2 conductors (2 signal wires and 2 power supply wires)
Commu-
nications
distance
2-conductor
VCTF cable
High-speed Communications Mode
Main line length: 100 m max.
Branch line length: 3 m max.
Total branch line length: 50 m max.
Long-distance Communications Mode
Main line length: 500 m max.
Branch line length: 6 m max.
Total branch line length: 120 m max.
4-conductor
VCTF cable
High-speed Communications Mode
Main line length: 30 m max.
Branch line length: 3 m max.
Total branch line length: 30 m max.
Long-distance Communications Mode: Flexibly branched, provided that the total length of
cable is a maximum of 200 m.
Special Flat
Cable
High-speed Communications Mode
Main line length: 30 m max.
Branch line length: 3 m max.
Total branch line length: 30 m max.
When 4-conductor VCTF cable or Special Flat Cable is used to connect fewer than 16
Slaves, the main line can be up to 100 m long and the total branch line length can be up
to 50 m in High-speed Communications Mode.
Long-distance Communications Mode: Flexibly branched, provided that the total length of
cable is a maximum of 200 m.

Specifications

I/O points 256 (128 inputs and 128 outputs) or 128 (64 inputs and 64 outputs) (Switch-
selectable)
Applicable PLC models CJ-series PLCs
Unit type Special I/O Unit
Allocated words * For 256 I/O: 20 words (8 for inputs, 8 for outputs, 4 for status)
For 128 I/O: 10 words (4 for inputs, 4 for outputs, 2 for status)
No. of mountable Master Units 40
Node address 8 addresses per node
No. of connectable Slaves 32
Status information Communications Error Flags, Participation Flags

* Uses Special I/O Unit Area (in CIO Area).