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Q: How to choose the output mode of a safety light curtain?

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Q: How to choose the output mode of a safety light curtain?

Update Time:2025/7/8

A:


The output mode (Output Type) of the safety light curtain mainly depends on your equipment control system requirements and safety level design requirements. The following are selection suggestions:


Application Scenario
Recommended output mode
Reason
General industrial automation system
PNP / OSSD
Quick response and strong compatibility
Japanese or old PLC control system
NPN
Matching control input type
Controlling high power devices (motors/contactors)
Relay output
Dry contacts are safer and can isolate high voltage
Requires a high safety level (such as PL e or SIL3)
OSSD (dual channel PNP)
Redundancy + self-test, meeting ISO 13849-1 standard
Use multiple light curtains in series and require intelligent control
OSSD + IO-Link
Remote diagnosis and parameter configuration


Additional suggestions:


· Confirm the input type of the PLC or control system (NPN/PNP/dry contact);

· Confirm whether the safety function level (such as SIL/PL) needs to be met;

· If the supporting equipment requires high-frequency start-stop control, OSSD or PNP solid-state output is recommended;

· If it is used for old equipment or electrical isolation is required, it is safer to use relay output.