You'll need to use Modbus RTU as I don't se a Click specific protocol. For RS232, use com 2 and make sure Modbus is selected as the port setup (default).

Check your cable pin out and ensure the following:

HMI RxD goes to PLC TxD

HMI TxD goes to PLC RxD

HMI 0V goes to PLC 0V

The baud rate, parity and stop bits need to match between devices. The HMI will be the master and the PLC the slave. I forget if the master is automatically node address 1 so just in case it is, set the PLC node address to 2.

You can view the Modbus addresses in the PLC through the address picker. Typically MODBUS 984 addressing is used.

All Modbus registers are 16 bits. For 32 bit access, two are used usually sequentially.

Example: PLC address DS1 (also a 16 bit integer) = Modbus address 400001, DS2 = 400002

PLC address DD1 (32 bit integer) = Modbus address 416385 and 416386. The HMI will know to use both addresses as long as you specifiy the first address and that it is to be viewed / treated as a 32 bit integer.

Floats can also be used (data will just be stored in that format)

I would create a data view element in your HMI for address DS1 and then try and read / write to that.

Hope that helps a bit :)