PSENopt ERR Pilz — Safety light curtain in lockout — alignment or OSSD error
At a glance
- Severity
- FAULT STOP
- Domain
- SAFETY
- Reference standard
- IEC 61496-1 / IEC 61496-2
- Product / context
- Light curtain alignment/OSSD error
What it means
The safety light curtain is in lockout or error state. The OSSD (Output Signal Switching Device) outputs are deactivated and the machine is in a safe state. The light curtain does not correctly detect the protective field.
Probable causes
- Misalignment between emitter and receiver (mechanical impact, vibration).
- Emitter or receiver lenses dirty (dust, oil, condensation).
- Fixed object in the detection field permanently interrupting the beams.
- Internal OSSD fault -- short circuit or open circuit on the safety outputs.
Where to start
Check the diagnostic LEDs on the light curtain. Does the LED indicate an alignment error or an OSSD error?
Full guided diagnosis in the app
The diagnostic tree for this fault has 7 guided steps with measurements, checks and resolutions. You'll find it in ElectraIQ, one of the five IndexOS apps: free, works offline.
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The same fault on other brands
More Pilz codes
- CH1≠CH2 — Safety relay does not reset — cross-channel fault or contactor feedback
- E-Stop CH1/CH2 — Emergency circuit open — E-stop pressed or wiring interrupted
- PSENmag error — Door/guard interlock open — safety limit switch tripped
- SYS ERR — Safety PLC in error state — F-CPU passivation