I am coding a MODBUS TCP Windows service in Python. When I use MODSCAN64 to communicate with my Windows Service, all looks good on the service side, but MODSCAN reports a Timeout error.
My hypothesis is that my response requires more information, hence MODSCAN is left waiting.
The MODBUS spec for TCP goes into great detail about the ADU and PDU of the request. The ADU includes the TCP header of seven bytes plus the MODBUS PDU (of variable length).
Nowehere in the spec do I see any mention that the response should also have a TCP header. Is one needed?
Or am I experiencing a real timeout? If so, how do I lengthen the timeout for TCP in MODSCAN64?
Here is a link to my stackoverflow question, which gives an example request and response from my application.
https://stackoverflow.com/questions/65078888/modscan64-gives-timeout-errors-for-all-responses
My hypothesis is that my response requires more information, hence MODSCAN is left waiting.
The MODBUS spec for TCP goes into great detail about the ADU and PDU of the request. The ADU includes the TCP header of seven bytes plus the MODBUS PDU (of variable length).
Nowehere in the spec do I see any mention that the response should also have a TCP header. Is one needed?
Or am I experiencing a real timeout? If so, how do I lengthen the timeout for TCP in MODSCAN64?
Here is a link to my stackoverflow question, which gives an example request and response from my application.
https://stackoverflow.com/questions/65078888/modscan64-gives-timeout-errors-for-all-responses