Modbus Rtu Communication Via Rs232C/Rs485 - IDEC FC6A-C16K1CE Communications Manual

6: M
ODBUS
Introduction
This chapter describes the Modbus communication functions for the FC6A Series MicroSmart.
Modbus communication allows the following two types of communication methods.
Serial communication with an external device connected to port 1 to port 3
•
"Modbus RTU Communication via RS232C/RS485" on page 6-1
Ethernet communication with an external device connected to Ethernet port 1
•
"Modbus TCP Communication via Ethernet Communication" on page 6-18

Modbus RTU Communication via RS232C/RS485

The FC6A Series MicroSmart supports the Modbus RTU protocol and can be used as the Modbus RTU master and the Modbus RTU
slave. When configured as a Modbus RTU master, the FC6A Series MicroSmart can monitor and change the data of Modbus RTU
slave devices. When the FC6A Series MicroSmart is configured as a Modbus RTU slave, the device data of the FC6A Series
MicroSmart can be monitored and changed from the Modbus RTU master device.
For the Modbus RTU master function and how to configure it, see "Modbus RTU Master Communication" on page 6-2. For the
Modbus RTU slave function and how to configure it, see "Modbus RTU Slave Communication" on page 6-8.
Modbus RTU Master
*1
Terminating Resistance
*1 When communication quality is unstable, add terminating resistance matched to the characteristic impedance to both ends. Use resistance with
a rating of 1/2 W or higher.
Note: The 16- and 24-I/O types have one cartridge slot and the 40-I/O type has two.
C
OMMUNICATION
Modbus RTU Slave 1
Shielded Twisted-pair Cable, total length 200 m
FC6A S M S A
ERIES ICRO MART LL
- -O T C
IN NE YPE OMMUNICATION
Modbus RTU Slave 31
Terminating Resistance
M FC9Y-B1730
ANUAL
*1
6-1