TCP program cannot talk to GE PQM

[Industrial System]

I was unable to use the TCP client program to talk to the GE Multinet -- Serial to Ethernet Converter which can be found in: http://www.geindustrial.com/cwc/products?pnlid=6&id=multinet&from=menu

My Modbus device has RS485 Communications setting:
1. Protocol = RTU (8 data bits)
2. Stop bit = 1
3. Parity = None
4. Baudrate = 9600

I modified the TCP client program and use a clone Modbus packet to send to the network. There are parameters I had configured: IP = 3.46.41.17 and Port number = 502. Using the TCP client, it establishes the communication. However, client program receives no response at all. The modbus packets that I created are a valid packets and they read coils or holding registers per user selection.

I wonde
r if I need to modify the ClientTCPCB function in order to receive any response. Attached is the sample code and Kindly advice what to do.

[JuanCarlos]

Hi,

I looked at your code and I don't see any problems with it. The only thing that I noticed is that you call DisableBreakOnLibraryErrors(...) which may be hiding some problems. Also the first parameter of your callback (handle) should be just an int; but should not make any difference.

Is there any way that you can test the communication of the GE unit? also make sure that you are opening the right port for data; some devices allow you to connect to different ports for different operations.

The first thing to check is whether there is data coming in; you can use some TCP monitoring software to check for activity at the port. There are some free tools out there for this.

I hope this helps.

Regards,

Juan Carlos
N.I.