Processes the discrete time signals from a sampler. It comprises a controlled subsystem with , a microprocessor, a sampler (mostly A/D converters) and a holding element (Figure A 9).
The sampler samples the controlled variables at defined sampling times. The microcomputer calculates the new correcting variable using the control algorithm, this new correcting variable is then supplied to the holding circuit (mostly D/A converters). This correcting variable is then available on the microcomputer's output until the next sampling time.