Not sure about the c-more, guessing you are using Modbus or ModbusTCP.
In the M340 any tags you want to access externally you will need to 'locate' (set an address). Go to the variable table, or right click on the variable and open data property window, now just put an address in the address field. Addresses are in the iec format, words are in the form %MW123, bits are in the form %M123
hope this helps