Build an unambiguous alarm register
Each alarm ID should be traceable to a PLC signal, triggering condition, class and visible message. Check for missing or duplicated IDs before importing or generating alarm entries.
- Compare the alarm list, PLC signals and HMI project.
- Record the text, language, alarm class and trigger condition.
- Maintain a change log instead of uncontrolled manual editing.
Write messages that support the operator
'Fault 132' rarely tells the operator what to investigate. A useful alarm message identifies the location, what happened and the appropriate next step under the approved operating procedure.
- Example: 'Conveyor 2 – motor protection tripped. Inspect locally under the approved procedure.'
- Use consistent equipment names and engineering units.
- Keep translations consistent across language versions.
Review alarm classes and acknowledgement
Acknowledgement, alarm clearing and reset are different events. WinCC Basic/Comfort/Advanced, Professional and Unified have different functionality depending on runtime, hardware and version.
- Agree which events require an operator acknowledgement.
- Test incoming, cleared and acknowledged alarm states.
- Confirm access rights and recording requirements.
Treat recipes as part of the control system
Recipes may contain limits, units, data types and default values that must match the PLC program. Parameter changes need a plan for old recipes and invalid values.
- Record parameters, units, ranges and default values.
- Test HMI-to-PLC transfer, including errors and timeouts.
- Clarify who may edit and activate recipes.
Test the whole signal path
A correct screen display alone is insufficient. Validation should link a specific event to its PLC signal, HMI display, acknowledgement and any logging. Include restart or communication failures where relevant.
- Document the stimulus and expected state.
- Verify messages, translations and handshakes.
- Keep actual results, deviations and software versions.
Agree on approval and recovery
An HMI update must be handed over in a form that the site team can maintain. Keep the approved project baseline, test documentation and responsible contacts clear. Regulated sites may require additional formal change control.
- Document versions and approval roles.
- Explain changed operator messages and procedures.
- Agree how to recover if the update must be rolled back.
Simple WinCC alarm test matrix
- Alarm ID / PLC tag: [unique reference]
- Stimulus: [triggering condition]
- Expected message: [local languages]
- Acknowledgement and reset: [expected behaviour]
- Outcome: [pass / deviation / version]
This is a general planning resource. Verify alarm configuration and acknowledgement against the actual WinCC version and the machine's safety requirements.