User`s manual

8
FX3U Series Programmable Controllers
User’s Manual - MODBUS Serial Communication Edition
1 Outline
1.1 Outline of System
1. Outline
This chapter outlines the MODBUS serial communication network.
1.1 Outline of System
The MODBUS serial communication network allows up to 16 slaves to be controlled by one master in
accordance with RS-485 to link devices, or one directly linked slave in accordance with RS-232C.
1) Up to 16 slaves can be controlled by one FX
3U MODBUS Master
2) Master and Slave functionality
3) RTU and ASCII mode
4) One channel per PLC can be used for MODBUS serial communication (1 MODBUS Master
channel or 1 MODBUS Slave channel)
5) Transmission speed up to 19.2 kbps
6) The MODBUS Master function uses a new PLC command dedicated to MODBUS serial
communication
Note
MODBUS Slave Nodes do not need to be numbered in any specific order.
.......
For selection, refer to
Chapter 3.
Communication
equipment operating
in accordance with
MODBUS RS-485
Communication
equipment operating
in accordance with
MODBUS RS-485
Communication
equipment operating
in accordance with
MODBUS RS-485
FX PLC FX PLC
FX PLC
Master station
Slave station No. 1 (01H)
500 m (1640' 5")
.......
17 units
Number of linked units
Total extension distance
For the specifications,
refer to Chapter 2.
.......
For wiring, refer to
Chapter 4.
+++
.......
For applicable PLC models,
refer to Section 1.3.
Important points and reference
chapter/section
System
.......
In the case of RS-485
Slave station No. 16 (10H)
Communication
equipment operating
in accordance with
MODBUS RS-232
Communication
equipment operating
in accordance with
MODBUS RS-232
FX PLC FX PLC
Master station
Slave station No. 1 (01H)
++
15 m (49' 2")
In the case of RS-232C
.......