Definition
The measurement of the process variables that must be controlled indicates whether a stable state has been achieved.
In detail
Control elements are specific process variables that significantly impact process output and must be monitored, such as temperature, pressure, and speed. Their measurement results directly reflect whether the process is stable, serving as the foundation of process control. Unlike Critical-to-Quality (CTQ) characteristics, control elements focus on process parameters rather than product characteristics; compared to ordinary process variables, they are screened and have clear control standards. Typical outputs include a list of control elements and their monitoring plans.
Example in practice
In chemical production, the temperature and stirring speed of the reactor are control elements. The operator records the temperature every half hour and adjusts immediately when it exceeds the set range. By continuously monitoring these elements, the stability of reaction conversion is ensured, reducing quality variation between batches.