Glossary · Automation software engineering and architecture
Control software
Also known as: Control program, Controller software
German: Steuerungssoftware
In industrial automation, control software is the software that directly controls a machine or process by reading inputs from sensors, executing control logic and writing outputs to actuators, typically running on a PLC, motion controller, DCS controller or embedded controller.
- Software engineering
In one sentence
Control software reads sensor inputs, executes control logic and drives actuators on a PLC, DCS or embedded controller.
Example
The control software of a filling machine reads the level sensor and flow meter, controls the filling valves and sequences the bottle transport.
How it applies
- Engineering: Control software is subject to real-time constraints, such as cycle times and reaction times, and runs on platforms with limited resources. It is typically written in IEC 61131-3 languages, IEC 61499 or C/C++ for embedded controllers.
- Commissioning and maintenance: Changes to control software directly affect machine behavior. They should be made under Change control, tested and documented, with the previous version kept for rollback.
- Documentation: Operating and service documentation must match the control software version: operating modes, alarms, parameters and sequences. Machine documentation should state the software version it describes, and the version should be readable on the machine.
Control software vs. safety-related software
Standard control software controls the process; safety-related software implements a Safety function, often on a Safety PLC. Safety-related software is developed under functional safety standards such as IEC 61508 or ISO 13849-1. Keeping the two clearly separated simplifies verification and change management.