By Dovydas Kersys · Chapter 30 of 58 in Machine Commissioning.
Before you begin: Follow the machine documentation, risk assessment, site procedures and lockout/tagout requirements. Commissioning can expose personnel to electrical energy, stored pressure and unexpected motion. Never defeat a safety function merely to make a test easier. Examples and diagrams are generic and must be checked against the actual machine.
Safety logic devices must be commissioned against the safety requirement, not only against the wiring diagram. Verify input architecture, output monitoring, reset mode, fault detection and diagnostics.
Why this matters during commissioning
Incorrect safety configuration can look normal until a single-channel fault occurs.
Commissioning procedure
- Confirm safety project/configuration revision and signature.
- Test each input channel independently where safe test methods permit.
- Verify cross-fault/discrepancy detection.
- Test external device monitoring or feedback from contactors.
- Confirm manual/automatic reset behavior matches design.
- Record safety software version/signature after final changes.
Common failure patterns
- EDM feedback bridged during commissioning and never restored.
- Safety output drives a standard relay not included in the monitored architecture.
- Incorrect reset mode.
- Safety PLC project online does not match released archive.
Evidence to record
- Safety project revision/signature
- Device test result
- Fault-insertion result
- EDM/reset result
- Final approval reference
FIELD RULE: Commission safety logic by creating safe, controlled fault conditions – not only normal conditions.
Appendix E. Safety Proof-Test Record
Print or duplicate this page as needed. Record actual measurements and references rather than relying only on check marks.
| Safety function | Initiating device | Expected safe state | Observed result | Reset/restart | Pass/fail |
|---|---|---|---|---|---|
Continue the series
- Previous chapter: Guards and Interlocks: Commissioning Guide
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Adapted from Machine Commissioning for Maintenance and Automation Technicians, by Dovydas Kersys. © 2026 Dovydas Kersys. Featured cover image is an AI-generated editorial illustration.