I'm trying to test the encapsulated modbus rtu over tcp by setting up a dummy TCP server that waits for the request and sends back a sample response. I'm currently a bit stuck as I'm getting "error reading registers - no response from device 2".
I've looked at the messages in wireshark and can confirm that the response is being sent.
The dummy tcp server gives:
RX: 0x02 0x04 0x00 0x00 0x00 0x02 0x71 0xf8 TX: 0x02 0x04 0x04 0x46 0xB0 0xFF 0x6D 0x5C 0x36
which looks fine to me for a modbus RTU read.
Request at 4, response at 5.
Anyone have any ideas?
Turns out it was my TCP server, rewrote it from ruby to python and works just fine.