Powering of modules
All modules have the signal part separated from the power part by a DC/DC converter and optotransistors. This means that the signal ground is completely separated from the power part and it is possible to connect the signal ground to power supply ground, and use three-wire connection.
As some modules are able to process low voltage (relays, 230 V AC inputs), the communication part is separated as well to increase safety.
The RCIO, RMIO and RXIO compact modules have all internal parts (power – analogue inputs – analogue outputs – binary inputs – binary outputs – communication) separated from each other. Note that if active sensors are connected with 0…10 V output, the AI ground must be connected to the G0 (24 V AC ground) so that the sensor output signal has a reference potential. The same applies for analogue outputs: when the valves and damper actuators use three-wire connection (G, Y, G0) the AO ground terminal must be connected to G0.
In general, it is recommended to use a separate transformer for supplying of the peripherals at larger installations.