Glossary · PLC and control programming
Programmable automation controller (PAC)
Also known as: PAC, Automation controller
German: Programmierbare Automatisierungssteuerung (PAC)
In industrial automation, a programmable automation controller (PAC) is a controller that combines PLC-style real-time control with capabilities typical of PC-based systems, such as multiple programming languages, larger memory, motion control, process control and extensive communication, on one platform.
- PLC programming
In one sentence
A programmable automation controller (PAC) combines PLC real-time control with PC-like performance, memory and communication.
Example
A packaging line uses one PAC for discrete logic, motion control of twelve servo axes and data exchange with the MES.
How it applies
- Engineering: The term was coined as a marketing category to distinguish multi-discipline controllers from simple PLCs. Today, the boundary is blurred: many controllers sold as PLCs offer the same functions. Selection should rely on required performance, languages, motion and communication features rather than on the label.
- Integration: PACs often serve as the link between machine control and higher-level systems, which makes their network interfaces part of the security concept, see IEC 62443.
- Maintenance: One controller running many functions means one point of failure. Diagnostics and spare-part planning should reflect that.
- Documentation: Use the term the vendor uses for the product, but describe the functions explicitly. A reader learns more from a list of what the controller does than from the category name.
PAC vs. PLC
PLC is the established generic term; PAC emphasizes broader functionality. Technically, both run control programs cyclically or event-driven, and most standards, including IEC 61131-3, apply to both. The existing Programmable logic controller (PLC) entry covers the general concept.