FPΣ User's Manual 
 
8.6 Program Controlled Communication 
221 
8.6.7 1:N Communication 
The FPΣ and the external units are connected using an RS485 cable. Using the protocol that 
matches the external units, the F159_MTRN instruction is used to send and receive data. 
RS485
Data registers (DT)
Data to be sent
Data received
Data is sent using F159_MTRN
Data is received in receive buffer
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, 
the connected device should not send a response to the FPΣ before the time t indicated below 
has passed. 
Baud rate  Response time 
19200bit/s  t > 1ms 
115200bit/s 
t > 200μs 
System register settings 
By default, the COM port is set to MEWTOCOL-COM mode. For 1:N program controlled 
communication, the system registers should be set as shown below. 
•  Settings for COM port 1 (FPG-COM3, FPG-COM4) 
No.  Name  Set value 
412 
COM port 1 - communication mode  Program controlled 
413  COM port 1 - communication format 
*)
 
Data length:  7 bits/8 bits 
Parity:   None/Odd/Even 
Stop bit:    1 bit/2 bits 
End code:  CR/CR+LF/None/ETX 
Start code:  No STX/STX 
415 
COM port 1 - baud rate 
*)
 2400–115200bit/s 
416 
COM port 1 - receive buffer starting address  0–32762 (initial value: 0) 
417 
COM port 1 - receive buffer capacity  0–2048 words (initial value: 2048 words) 
*)
 The setting must match the external device connected to the communication port. 
 
NOTE
 
•  When the RS485 port (COM port 1) of FPG-COM4 is used, set the baud rate 
in the system registers to either 19200bit/s or 115200bit/s. Set DIP switch 
SW1-2 of the cassette to the same setting (see page 
162).