FMD1616-10 - RS232 communication

[kajag]

I used the RS232 cable I bought from TRIPLC. I run the utility provided with the software and set up the COMM1 port parameters- 9600,N,8,1. The PC COM port is set with identical values - 9600,N,8,1.  The switchws SW1-4 are set to "ON". When I send "IR*" or any other string or even just a <CR>, the utility software times out. "No response from PLC". So I did some hardware debug. The Tx line from the PC shows -10V to +12V signals when the cable is not connected to the PLC COMM1. (the data is "05 Hex [ENQ]"). When the cable is connected to  the COMM1, there is no signal. The manual says the COMM1 is configured as a DCE, and the cable is a straight 1:1 cable. Writing the PLC program and simulating it was the easy part.

[support]

FMD1616-10 default baud rate for both RS232 and RS485 ports are 38400, 8, 1, n.

Have you ever program the PLC and changed its RS232 port to 9600 using SETBAUD command? If not, then it will not work at 9600.

Also note that if you use a serial terminal to communicate with the PLC then you have to send the command in multipoint format. i.e. if the PLC ID = 01, send command as "@01xxxxxxxx00*

"00" is used as the wildcard FCS so that you can manual test the sending of the serial command without having to compute the actual FCS.

To use point to point protocol without the ID, you must send the Ctrl-E character before the command.

The best way to test is to use TLServer.