NE194 NAMUR APC Interface has been released

The NAMUR recommendation NE194 from WG 2.2 Process Operation has been newly published and can now be obtained from the office.

Abstract to NE 194 "NAMUR APC Interface"

The NAMUR recommendation NE194 defines a standardized interface for the seamless integration of external Advanced Process Control (APC) applications into process control systems (PCS). The aim is to enable and to facilitate the application of APC solutions such as Model Predictive Control (MPC), soft sensors or optimizations.

The interface consists of several core elements: A state machine for controlling the switch-on and switch-off process of the external application, a validity check for transmitted process data and manipulated variables with configurable limit values, gradients and freeze times, a watchdog for monitoring the availability of the application, the possibility to trigger alarms and notifications and a visualization and operating function in the PCS.

For applications that directly impact the process, like an MPC providing setpoints, the guideline covers switching the application on and off through defined preparation, switch-on and switch-off processes. It specifies managing write access from the external application to manipulated variables in the control system, defining fallback logic when switching off, and handling partial operation scenarios. For applications without direct process impact, like soft sensors providing calculated values, the recommendation focuses on implementing appropriate fallback logic upon switching off the application.

NE194 describes the functional requirements in detail for the standardized APC interface and provides two example use cases.