The Expansion Transmitter Module (*ETM001) is used to expand a PLC or NIU I/O station to accommodate up to seven additional "racks" of modules. Each expansion rack can accommodate up to eight I/O and specialty modules, including fieldbus communication modules.

Expansion Connector

The 26-pin D-type female connector on the front of the expansion transmitter is the expansion port for connecting the expansion receiver module. There are two types of expansion receiver modules: isolated (module *ERM001) and non-isolated (module *ERM002).

By default, the module is set to use the maximum extension cable length and the default data rate is 250 Kbits/sec. In a PLC system, if the total extension cable length is less than 250 meters and there are no non-isolated extension receivers (*ERM002) in the system, the data rate can be configured to 1 Mbit/sec. In an NIU I/O station, the data rate cannot be changed and defaults to 250 Kbits.