Telemecanique Safety Interlock Switches: XCSE & XCSLF Guard Locking Guide
Solenoid guard-locking switches that keep machine doors shut until it is safe to open.
Some machines keep moving after you press stop — a spindle runs down, a blade coasts, a robot finishes its move. A plain door switch cannot protect against that. A Telemecanique safety interlock switch with guard locking holds the door closed with a solenoid until the control system confirms the hazard has stopped. This guide explains how the metal XCSE and XCSLF switches work, which locking principle to choose and how to wire them into a safety circuit.
Interlock or Guard Lock?
Interlock switch
Detects whether the guard is closed and stops the machine the moment it opens. Right for hazards that stop instantly.
Guard-locking switch
Holds the guard closed with a solenoid until the machine is safe. Needed when the hazard keeps running after stop — long run-down times, hot or pressurised processes.
Coded actuator
A separate key-style actuator mounted on the door enters the switch head. The switch only closes its safety contacts when the correct actuator is fully inserted.
Power to Release or Power to Lock?
| Principle | How it works | When to use |
|---|---|---|
| Locked when solenoid is OFF (power to release) | A spring holds the lock; energising the solenoid releases it. XCSE7311 family works this way. | Default choice for personnel protection — a power failure keeps the guard locked |
| Locked when solenoid is ON (power to lock) | Energising the solenoid locks the guard; losing power releases it. Available in the XCSLF range. | Process protection, or where operators must be able to leave after a power cut |
The choice must follow the machine risk assessment (ISO 12100 / ISO 14119).
XCSE vs XCSLF at a Glance
| Feature | XCSE (e.g. XCSE731122) | XCSLF |
|---|---|---|
| Body | Metal (Zamak) | Metal (Zamak) |
| Contacts | 2NC + 1NO main, plus solenoid monitoring contacts | Versions such as 2NC+1NO or 2NC+4NO |
| Solenoid | 24 V AC/DC | 24 V AC/DC |
| Locking principle | Locked on de-energisation | Both principles available |
| Protection | IP67 | IP66 / IP67 |
| Holding force | — | 3000 N resistance to forcible withdrawal |
Telemecanique Safety Switches in Stock
Wiring Into a Safety Circuit
- Use the NC safety contacts for the stop circuit. The positively driven NC contacts go to a safety relay or safety controller — never directly to a PLC input alone.
- Monitor the lock. Wire the solenoid-monitoring contacts too, so the controller knows the guard is both closed and locked before restarting.
- Release only on a safe signal. Drive the solenoid from a standstill monitor or timer so the guard opens only when motion has stopped.
- Provide an escape or manual release. Where a person can be trapped inside, fit the manual or key release recommended by the manufacturer.
- Test after installation. Try to open the guard while running — it must stay locked — then check it releases only after stop.
Safety Interlock Switch FAQs
What is the difference between an interlock switch and a guard-locking switch?
A standard interlock switch only reports whether the guard is open or closed. A guard-locking switch such as the Telemecanique XCSE or XCSLF also holds the guard shut with a solenoid until the control system allows it to open, so an operator cannot reach in while a spindle or blade is still running down.
Does the XCSE lock with power on or power off?
The XCSE7311 family locks when the solenoid is de-energised and unlocks when it is energised (power to release). This is the fail-safe choice: if power is lost, the guard stays locked.
Which XCSLF versions are available?
The XCSLF family is offered with both locking principles — locking on de-energisation or locking on energisation of the solenoid — and different contact combinations such as 2NC+1NO or 2NC+4NO. The part number tells you which version it is, so confirm it before ordering.
What safety level can these switches reach?
According to Telemecanique, XCSE and XCSLF switches can be used to reach Category 4, PL e and SIL 3 when they are wired correctly and monitored by a suitable safety relay or safety controller, following ISO 13849-1 or IEC 61508.
How strong is the XCSLF guard lock?
Telemecanique specifies a resistance to forcible withdrawal of the actuator of 3000 N for XCSLF models, with an extraction force of 20 N in normal operation.
Need Help Choosing a Guard-Locking Switch?
Send us the machine type, stopping time and door arrangement. We will suggest the right Telemecanique switch and quote from stock.
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