By Jürgen Schemel, Field Applications Engineer, Analog Devices

Today’s typical programmable logic controller (PLC) contains a multitude of analog and digital outputs for the control and monitoring of industrial and production processes. Modularisation is widespread and, with respect to inputs and outputs (I/Os), covers the basic functions of analogue and digital I/Os.

The analogue output presents a particular challenge because as a set value must be driven actively and with high accuracy under numerous different load conditions. The active driver stage is important here; losses should be kept as small as possible.