Glossary · Batch and process operations
Procedural control (ISA-88)
Also known as: Procedure control
German: Prozedursteuerung
In ISA-88 batch control, procedural control is control that directs equipment-oriented actions to take place in an ordered sequence in order to carry out a process-oriented task. It is one of the three types of control in ISA-88, alongside basic control and coordination control.
- Batch control
- Process industry
- Standards
In one sentence
In ISA-88, procedural control directs equipment-oriented actions in an ordered sequence to carry out a process-oriented task.
Example
Procedural control runs the phases charge, heat and hold in sequence, while basic control keeps the valve and temperature loops working.
How it applies
- Engineering: Procedural control is what makes batch processes batch-like: it sequences phases and operations. Basic control (device control, regulation, interlocks) runs in control modules; coordination control allocates equipment and arbitrates shared resources.
- Operation: Procedural control is where operators see the progress of a batch and interact with holds and confirmations.
- Validation: In regulated industries, procedural control logic is tested against the recipe and process requirements.
- Documentation: Separating basic, procedural and coordination control in the functional specification helps readers find behavior. Interlocks belong to basic control and should be documented at the device, so they remain active whatever the procedure does.
Procedural control vs. basic control
Basic control keeps devices and loops in a desired state and enforces interlocks. Procedural control tells equipment what to do next in a sequence. Safety functions should not depend on procedural control.