I am having trouble connecting a CO2-N via Modbus to an Schneider m241 PLC. I have also tried connecting to the CO2-N with a generic Modbus software using a USB to RS485 converter. The only way I can connect to the device is with the T-3000 software, or the Modbus tool again using the USB to RS285 converter. I used the connection settings from the Modbus tool to configure everything (baud rate, parity, function code, ect…). I have set the CO2-N to a device address of 201, and a baud rate of 9600.
I have previously been using the CO2-W with Modbus in all our previous projects with no issues on the same m241 PLC.
The logs from the generic Modbus software state
10/16/19 12:02:02 - Slave ID = 201 - Fragment received, timeout waiting on a complete/correct response
10/16/19 12:37:52 - Slave ID = 201 - Timeout waiting on a response
10/16/19 12:42:08 - Slave ID = 201 - Exception response received - type 128