Digital inputs and outputs are a standard part of RTU systems. For digital inputs, you need to choose the correct variant of the card according to the type of contact:
1. Active (dry contact) - the card itself provides 24 V DC power and switching occurs by connecting the active source terminal to given input.
2. Passive (wet contact) - card inputs are set for a given voltage level from an external source.
For cards with digital outputs, you can choose cards with ten mechanical relays (higher switching currents) or twenty electronic relays (more outputs, lower switching currents, suitable for large systems with separate relay cabinets - interposing relays).
In the offer you will also find combined input and output cards for applications where less I/Os are needed and thus it is possible to save space in the bus.