Digital input modules convert the level of the external digital signals from the process to the internal signal level (logical "0" or "1") of the controller.

Various input voltages support the connection of different process signals:

• 24 V DC
• 48 to 125 V DC
• 120/230 V AC

Apart from cost-effective, easy-to-handle modules, modules with special functions are also available:

• For use in isochronous mode
• Process and diagnostic alarms
• Use for current sourcing or current sinking

Special modules are also available for process engineering which, for example, support the NAMUR standard.