The Door Interlock Switch

How does the interlock switch on your laser enclosure work?

The interlock on our fiber and UV laser enclosures is a magnetic door switch: a sensor on the frame, a magnet on the door, and a two-wire lead coming out of it. It's a dry contact — no power, no board, no software. We build it this way on purpose. Every laser manufacturer uses a different physical interlock connector, but underneath, nearly all of them want the same thing: a two-wire loop that's either open or closed. The FDA rule that governs this (21 CFR 1040.10(f)(3)) specifies the behavior — break the connection and emission has to stop — but nothing standardizes the plug. So rather than hard-wire a connector that fits one machine and strands everyone else, we supply the switch and let whoever has your machine's manual land the two wires.

Will the interlock work with my laser?

If your machine's interlock goes to two screw terminals or a plug on the controller, the switch drops straight in: pull the factory shorting jumper from the interlock terminals and put the switch in its place. Usually under 30 minutes for a controls tech. If your machine's interlock runs into a safety relay or safety PLC, or your safety program requires a specific interlock type, it would be up to your team to implement that; our switch is a magnetic sensor with a two-wire setup. A photo of your machine's interlock terminals, or the page from the manual, is enough for us to tell you which case you're in.

Who is responsible for what?

• We supply: the enclosure, the sensor and magnet, the mounting, and the pass-through.
• You or your engineer supply: identifying your machine's interlock terminals, the configuration choice, the wiring, and the functional test.
• We don't: spec your machine's terminals or certify your laser's classification. This enclosure doesn't change your machine's FDA-certified class.

Should I wire it normally open or normally closed?

"Normally" means the at-rest state with the magnet away — door open. Most people read it backwards. Use NO for nearly all lasers: door closed = circuit closed, replacing the factory shorting jumper. With that wiring, a cut wire, a pulled connector, or a failed sensor all read as "door open," so the machine refuses to fire rather than thinking the door is shut. Use NC only if your machine's manual or PLC input specifically calls for it.

Can I cover the viewing window during operation?

There's no provision to cover or block the laser viewing window during use. If your application calls for no window, we build the door solid — ask for it when ordering.

What does the enclosure certify?

This enclosure provides OD6+ laser safety windows and includes magnetic door interlock(s) intended to inhibit laser operation when the enclosure is opened, as an engineering control consistent with an ANSI Z136.1 laser-safety program. It is NOT a certified Class 1 laser enclosure: the interlocks are not fail-safe/redundant safety-rated interlocks, and the unit carries no laser-safety classification or certification under IEC 60825-1 / 21 CFR 1040.10. The operator and their Laser Safety Officer remain responsible for laser-safety compliance.

Last updated 2026-10-08.