Modbus RS485 to Phoenix Contact Ethernet Converter to CI867 comms issue
I am having an issue with a Modbus RS485 to a Phoenix Contact Ethernet Converter to a CI867 module. The MBTCPConnect function in the read program is giving error codes of -4904 and sometimes -7004. I would like to "dump" out all the data that is being read in by the MBTCPConnect function to a text file in order to analyze what data is being pulled in and whether the RS485 serial data connection is currently giving good data. The FB needs a Comm_Channel_MBTCP type variable in order to function, however this ID is empty on this FB and other known good MBTCPConnect FBs.
Also, the program is built to "pulse" data requests every 4 seconds. Is there a purpose for this pulsing behavior vs reading the serial connection constantly?
I have looked at a variety of CI867 and AC800M manuals. Along w/ the Phoenix Contact and the manuals for the boiler and compressor that we are attempting to connect to.
Any tips or help would be greatly appreciated.
Voted best answer
Wireshark can be used to inspect the Ethernet packets between the EtherNet Convertor and the CI867 .... https://www.wireshark.org/
Google your favourite Modbus Anayzer, theres a bunch available but this one looks promising ... https://ioninja.com/purchase.html (Not an endorsement, I've not used it )
-7004 The Slave isn't responding or its responding with an exception code.
-4904 is again, an exception code.
In both cases your remote PLC is saying that it received your message but it can't respond to it. EG its an invalid memory address, unsupported command code etc.