GE IC695CMM002 modbus module

hey guys,

I have the following set up:

two protection relays. one serial interface module connected to each relay. The serial modules daisy chain connected to one protocol converter. all of these devices are proprietary owned. the GE IC695CMM002 modbus module on the PLC connects to the Protocol converter.

a diagram is attached.

I have set the modbus module to master, and the protocol converter to slave. In the hardware configuration in Machine Edition, I have set the station address to '1', because this is the ID of the protocol converter.

My question is, what is the 'target address'? I have read a few manuals, but they don't really give me enough of a description (for me anyway). could somebody please shed some light on what that configuration stands for???

cheers guys, any help is good help.

Somewhere in your documentation for the protective relay there should be a description of how the variables in that device are mapped into Modbus addresses.

Numeric data is usually located in 4xxxx address space although it could also be located at 3xxxx addresses. The difference is that a master can read and write to 4xxxx addresses, while 3xxxx addresses are read-only.

Discrete data can be located at 0xxxx or 1xxxx addresses. 0xxxx are read/write. 1xxxx are read-only.

You do realize, I hope, that you'll have to write the logic for controlling the Modbus master. Modbus is a master/slave protocol. The master initiates all communications with the slaves. The slaves can only respond to commands from the master.