Topic
Compliance
Regulated automation: GAMP 5 validation, 21 CFR Part 11, ALCOA+ data integrity, and the ISA-88 and ISA-95 models that structure batch and enterprise systems.
7 articles
Factory acceptance test checklist for a PLC control panel
A PLC panel FAT checklist covers, in order: entry criteria and documents, visual and mechanical inspection, power-up and electrical tests, every I/O point, functional tests from the FDS, every interlock and safety function, alarms and HMI, communications and failure modes, a graded punch list, and signatures. Each check records the expected and actual result, the tester and the date.
9 min readFunctional design specification for a PLC system: what goes in it
A functional design specification (FDS) says how a control system will meet each user requirement, in enough detail that another engineer could program it and a tester could write the FAT from it. For a PLC system that means architecture, operating modes, numbered sequences with transitions and timeouts, interlocks, alarms, analog handling, operator interface, communications, failure behaviour, software structure and a traceability table.
11 min readGAMP 5 for control engineers, without the consultancy
GAMP 5 is ISPE guidance for validating computerised systems in regulated manufacturing. It classifies software by category, 1 for infrastructure up to 5 for bespoke, and scales the validation effort to the risk each part carries. For a PLC, the configured application is usually Category 4 and any custom code Category 5, which means specified, reviewed and tested against the specification, with the evidence retained.
8 min read21 CFR Part 11 where the PLC is concerned
Part 11 applies wherever a system creates, modifies or maintains records required by predicate rule in electronic form. For a PLC and its HMI that usually means batch records, alarm and event history, and any parameter change affecting product quality. The requirements that bite are secure attributable access, a computer generated audit trail of changes with the old and new value, and the ability to produce accurate copies for inspection.
8 min readISA-88 in practice: recipes, equipment and the separation between them
ISA-88 separates what to make from the equipment that makes it. The physical model divides the plant into process cells, units, equipment modules and control modules; the procedural model divides the recipe into procedures, unit procedures, operations and phases. The rule that makes it work is that a recipe names phases and parameters, never specific equipment, so the same recipe runs on any capable unit.
8 min readISA-95 levels, and where your data actually has to go
Level 0 is the process itself, sensors and actuators. Level 1 is sensing and manipulating, the instruments. Level 2 is monitoring and supervisory control, the PLCs and SCADA. Level 3 is manufacturing operations management, scheduling, dispatching and the production record. Level 4 is business planning and logistics, the ERP. Most integration difficulty sits between levels 3 and 4, where a production event has to become a business transaction.
7 min readALCOA+ as a design checklist, not an audit finding
Attributable, legible, contemporaneous, original, accurate, plus complete, consistent, enduring and available. Applied to a control system: every record traceable to a person, readable without the original software, recorded at the time rather than later, kept as first captured, correct, whole, in a consistent order, retrievable for its full retention period, and accessible when asked for.
7 min read