Power-to-Lock Safety Solenoid Switch
Power-to-lock (also called energised-to-lock) solenoid interlock switches lock the guard when 24VDC is applied to the coil and release when power is removed. Preferred for process protection where a machine must complete its cycle before the operator can open the guard.
Power-to-LockProcess Protection24VDC CoilIndia Supply
Power-to-lock vs spring-to-lock: Power-to-lock releases on power fail (guard opens) - fine when process protection is the goal. For personnel protection where the guard must stay locked even on power fail, use spring-to-lock (mechanical latch, energised-to-unlock).
When to Use Power-to-Lock
- Process protection - guard must stay closed until PLC confirms end of cycle.
- Machines where dangerous motion stops immediately on E-stop / power loss.
- Setups where operator access is fine when powered down.
Popular Power-to-Lock Models
| Schmersal | AZM 200 (power-to-lock variant) |
|---|---|
| Omron | D4NL-...G4A (power-to-lock) |
| Allen-Bradley | TLS-Z power-to-lock version |
FAQ
Which is safer, power-to-lock or spring-to-lock?
Depends on hazard. Spring-to-lock is safer for personnel protection; power-to-lock is fine when process protection is the concern.
Can I convert one to the other?
No, the actuator mechanism differs; select the correct variant at order.