Telemecanique Safety Limit Switch: Positive Opening IEC 60947-5-1 Selection Guide
What positive opening actually guarantees, why the component alone is not the safety function, and which series to specify for guarding.
Telemecanique Limit Switches We Stock
Metal-bodied OsiSense XC switches with positive opening NC contacts, supplied across India.
Telemecanique Safety Limit Switches & Positive Opening Contacts
A limit switch used in a machine safety circuit must do more than switch reliably — it must fail safe. The property that makes this possible is positive opening operation: the NC contact is driven open by direct mechanical action from the actuator, so it cannot remain closed if the contact welds or the return spring fails.
What positive opening actually means
In an ordinary switch, the NC contact closes and opens under spring force. If that contact welds shut, or the spring breaks, the circuit stays closed and the machine believes the guard is still safe.
With positive opening operation, the actuator drives a rigid mechanical linkage that forces the contact apart. There is no spring in the safety path. A welded contact is torn open by the force of the guard being moved. This behaviour is defined in IEC 60947-5-1 Annex K and is marked on the product with the positive opening symbol — an arrow inside a circle.
Telemecanique states that its European standard products generally feature positive opening contacts, including in snap action versions, which allows their use in safety applications.
Selecting for a safety function
Positive opening on the component is necessary but not sufficient. The safety function is a property of the whole circuit — switch, wiring, logic and actuator — and must be assessed against ISO 13849-1 or IEC 62061 for the required performance level or SIL.
In practice this usually means two independent switches with dual-channel monitoring, positively driven so a single fault cannot defeat the guard, mounted so the guard cannot be defeated by hand, and evaluated by a safety relay or safety PLC rather than a standard input.
Which series to specify
For guard and interlock duty, the metal-bodied series are the usual choice. XCKJ is the most robust head in the range on an EN 50041 industrial body. XCKM and XCKL offer the Classic zamak body with three and one cable entries respectively. XCMD provides positive opening contacts in the compact EN 50047 miniature format where space is limited.
For hoisting and travel limits, XCRE and XCRF are complete units with positive opening contacts, and XCKMR offers one positive opening contact per position for single or double speed travel limit control.
Environmental and approval data
Sealing is IP66 to IEC 60529 on metal Classic bodies and IP66/IP67 on compact models. Operating temperature is -25 to +70 °C. Shock resistance is 50 gn for 11 ms per IEC 60068-2-27 and vibration 25 gn from 10 to 500 Hz per IEC 60068-2-6. Approvals include IEC/EN 60947-5-1, UL 508 and CSA C22.2 No 14, with CCC on selected references.
Series for guard and interlock duty
| Series | Format | Why specify it |
|---|---|---|
| XCKJ | Industrial EN 50041 | Most robust head, plug-in body |
| XCKM | Classic EN 50041, zamak | Three cable entries, daisy-chain wiring |
| XCKL | Classic EN 50041, zamak | One cable entry, simpler installation |
| XCMD | Miniature EN 50047 | Positive opening in a small envelope |
| XCRE / XCRF | Hoisting units | Complete travel limit units |
| XCKMR | Travel limit control | One positive opening contact per position |
All OsiSense XC models carry IEC/EN 60947-5-1, UL 508 and CSA C22.2 No 14 approval, with CCC on selected references.
Telemecanique products in stock at IndustryPapa
We are a Telemecanique Sensors stockist in India. OsiSense XC limit switch bodies and heads are supplied to order against your reference; the products below are held on the site and can be ordered directly.
Telemecanique position and safety switches
XCSLF SeriesMetal safety switch, 4 NC + 2 NO, slow break, 3 entries tapped M20, 24 VView product →
XCSE SeriesMetal safety switch, 2 NC + 1 NO, slow break, 2 entries tapped M20, 24 VView product →
XCSE731122Metal safety switch, 2 NC + 1 NO, slow break, 2 entries tapped Pg 13, 24 VView product →
Full Telemecanique range on site
| Reference | Type | Description |
|---|---|---|
| XCSLF Series | Safety interlock switch | Metal body, 4 NC + 2 NO, slow break, M20 entries |
| XCSE Series | Safety interlock switch | Metal body, 2 NC + 1 NO, slow break, M20 entries |
| XCSE731122 | Safety interlock switch | Metal body, 2 NC + 1 NO, slow break, Pg 13 entries |
| XT218A1PCM12 | Capacitive proximity sensor | Cylindrical M18, plastic, Sn 8 mm, 12-24 V DC |
| XT230A1PAL2 | Capacitive proximity sensor | Cylindrical M30, cable connection |
| XUM8APXBL2 | Photoelectric sensor | Miniature photoelectric detection |
| XUYFANEP40015 | Photoelectric sensor | Fork sensor, 40 mm slot |
| XUVE04M3KSNM8 | Label sensor | Transparent label detection, M8 connector |
| XUVU06M3KSNM8 | Label sensor | Ultrasonic label detection, M8 connector |
Frequently asked questions
What is a positive opening contact?
A positive opening contact is an NC contact that is forced open by direct mechanical action from the actuator rather than by spring force. It conforms to IEC 60947-5-1 and is marked with an arrow-in-circle symbol. It cannot stay closed if the contact welds or the return spring fails.
Is a positive opening limit switch enough to make a machine safe?
No. Positive opening is a necessary property of the component, but the safety function belongs to the whole circuit. Assess the complete system against ISO 13849-1 or IEC 62061 to establish the required performance level, which normally calls for dual-channel monitoring through a safety relay or safety PLC.
Can a snap action switch be used for safety?
Yes, if it has positive opening operation. Telemecanique European standard products generally feature positive opening contacts even in snap action versions. Confirm the positive opening symbol appears on the specific reference you are ordering.
Which Telemecanique series is best for machine guarding?
Metal-bodied series are usual for guard duty: XCKJ for the most robust industrial applications, XCKM or XCKL for Classic EN 50041 installations, and XCMD where the EN 50047 miniature format is needed. Mount so the guard cannot be defeated by hand.
Need a Telemecanique safety limit switch?
Tell us the guard arrangement and the performance level or SIL you are working to, and we will confirm suitable references. We supply the components; the safety assessment of the complete circuit remains yours. GST invoicing and pan-India dispatch.
☎ Call +91 99530 39482 WhatsApp EnquiryTelemecanique limit switch dealer and supplier — major cities
We supply Telemecanique OsiSense XC limit switches across India with GST invoicing and same-day dispatch on in-stock items. Local pages for the cities we ship to most:
Not listed? We deliver pan-India. Call or WhatsApp +91 99530 39482 with your reference and delivery pin code.