Glossary · Verification and validation
Alignment check
In functional safety, an alignment check is the verification that a sensing or guarding device remains in its intended physical position and orientation. Misalignment can change detection zones and safety distances even when the device still reports no fault.
- Verification
- Functional safety
In one sentence
An alignment check confirms that a sensor or guard is still in its intended position, because a shifted device can protect the wrong area.
Example
After a forklift brushes the column of a palletizer, the maintenance technician checks the light curtain alignment with the test rod and verifies the mounting marks against the commissioning record.
How it applies
- Machine safety: The minimum distance of a light curtain or scanner is calculated for one mounting position. If brackets shift, the calculation no longer describes the machine.
- Technical documentation: Give reference values in the commissioning record (mounting heights, distances, marks) and describe the check in the maintenance manual: when, how, with which tool and what to do on deviation.
- Evidence: Record each check with date, result and person. Checks after collisions, repairs and relocation are as important as scheduled ones.
- Integrated systems: Scanner fields configured in software must also match the physical position. Keep the field configuration file under version control and compare it during the check.
Alignment check vs. functional test
A functional test shows that the device reacts. An alignment check shows that it reacts in the right place. A misaligned safety light curtain can pass a functional test and still leave a gap.