Communication 
 
FPΣ User's Manual 
182 
•  Using the 1-channel RS485 and 1-channel RS232C combination type communication 
cassette (FGP-COM4): 
5
1
2
3
4
SG
SD
RD
RS
CS
SG
+
-
SD
RD
 
Left: GT terminal, right: FPΣ 
 
REFERENCE
 
Please refer to the "GT Series Technical Manual" for more information. 
 
8.5.6 1:N Slave Communication 
For a 1:N MEWTOCOL-COM connection between a computer and several PLCs, the 
computer and the first PLC are connected through a commercially available RS232C-RS485 
converter. The other PLCs are wired using an RS485 cable. 
The computer and the PLCs communicate via commands and responses: The computer 
sends a command specifying the station number, and the PLC with that station number sends 
a response back to the computer. 
RS232C
RS485
#1 #2 #3 #4
 
1:N communication between a computer and several PLCs 
1
 
The station number of the PLC to which the command is being sent is included in the command message. 
2
 
The station number of the PLC sending a response is included in the response message. 
3
 
Commercially available converter 
#  Station number of PLC 
 
The RS485 port of FPG-COM4 occupies the communication line for a certain period of time 
after sending data. During this time, data cannot be received from another device. Therefore,