How many PRM modules does the PR supports?

Maximum two modules can be connected in series to PR102, PR103, PR200, PR205.

With these modules, you can extend the PR by up to 16 additional digital inputs and up to 16 digital outputs. Alternatively, if your system requires more I/O-points, you can use Modbus RTU/ASCII and connect up to 32 expansion modules over the RS485 interface. We recommend using our I/O-Modules of the Mx110 series for this purpose. For model with Ethernet (PR103, PR205) you also can use Mx210.