DX-W5 / DX-D2D3 / DX-W3 / DX-W2 industrial machine tool safety door locks
Safety Door Lock Products
How to Choose the Right Safety Door Interlock Switch for Your Machine Guarding System
Model-specific mounting illustration: the shown dimensions must not be applied to a different switch or actuator.
Start with Three Questions (30-Second Decision)
Q1: Residual hazardous energy / inertia?
If the hazard can be reached before it has ceased, evaluate a locking safety interlock (DX-D6) with suitable monitored locking and release arrangements. Confirm that unlocking occurs only when access is safe.
If the hazard can be reached before it has ceased, evaluate a locking safety interlock (DX-D6) with suitable monitored locking and release arrangements. Confirm that unlocking occurs only when access is safe.
Q2: Tough door & environment?
For large doors, vibration, dust / oil mist or cleanrooms, pick coded non-contact (DX-R1) — then verify its documented alignment, ingress protection and anti-defeat measures for that environment.
For large doors, vibration, dust / oil mist or cleanrooms, pick coded non-contact (DX-R1) — then verify its documented alignment, ingress protection and anti-defeat measures for that environment.
Selection Matrix (Risk → Environment → System Requirements)
| Scenario / Pain Point | Recommended Model | Why This | Typical Applications |
|---|---|---|---|
| High risk / inertia — door must stay locked | DX-D6 (locking) | Verify locking/guard monitoring, holding force, release principle, safety interface and connector for the exact ordering code. | Presses / press brakes, robotic cells, welding & cutting units |
| Anti-bypass, wide tolerance, multi-door | DX-R1 (coded non-contact) | Verify coding level, actuator compatibility, operating distances, safety interface and any permitted series arrangement. | Perimeter guarding with many doors; dusty / oily or clean environments; vibration |
| High safety-performance target & large-door misalignment | DX-R1 (coded non-contact) | Check exact-model safety data and mounting limits against the required PL / SIL. The product family name alone does not establish the achieved system level. | Large assembly / packaging lines, big service doors |
| Standard service / guard doors (value) | DX-D2 / DX-D3 position-monitoring interlock | No guard-locking function. First confirm that position monitoring is sufficient for the access and stopping times, then check the exact contacts and controller. Pairing components alone does not establish the achieved PL / SIL. | General machining, common service access |
| Form-factor / mounting compatibility add-ons | DX-W2 / DX-W3 / DX-W5 | Broader shapes & mounting options to match existing holes and space constraints. | Limited space or specified appearance compatibility |
Outputs & Interfaces
Identify safety contacts versus OSSD outputs and verify the exact controller input, supply, test-pulse compatibility and pinout. An auxiliary status output is not a safety channel.
Coding & Cascading
Confirm the exact coding level and anti-defeat measures. Approved series connections may affect diagnostics and response time; account for fault masking and the whole safety function.
Mounting & Door Types (Eliminate Physical False Trips)
For two-leaf access, use the double-leaf guard door and bolt selection guide to distinguish structural support, position monitoring and guard locking.
Hinged / Pivot Doors
Use rigid hinge-style brackets; in high-risk stations prefer locking DX-D6 with official brackets to mitigate sag and vibration.
Sliding Doors
For rail dust / side-play, check approved brackets and alignment limits. Evaluate non-contact sensing only where suitable; it cannot replace a required guard-locking function.
Wiring & System Integration (One-Page Field Guide)
- Safety interface: connect the documented contacts or safety outputs to compatible safety logic. Verify the whole sensor–logic–final-element function, not just the number of channels.
- Multi-door cascading: use only the manufacturer-approved arrangement for the exact devices. Include fault masking, diagnostic coverage and accumulated response time in validation; keep auxiliary status signals separate from the protective function.
- Coding: verify the documented coding level and anti-defeat measures; follow the specified operating and release distances.
- Power & EMC: use the specified supply, cable routing, shielding and grounding for the exact switch and controller.
For brand-replacement checks, compare Euchner and Schmersal interlock functions against DX candidates or review the Pizzato and Fortress replacement requirements. Select compatible safety relay modules for guard-door monitoring only after checking the input and reset requirements.
Standards & Compliance (Check-off for Selection & Acceptance)
Selection principles: guard locking and access versus stopping time. For a model-specific example of series-connection limits—not DX specifications—see Schmersal operating instructions.
Document these in your project file: target PL / SIL, locking requirement, coding & anti-bypass strategy, multi-door cascading, door type & bracket, I/O type and connector.
FAQ: The 6 Most Common Questions
1) When is a locking safety interlock mandatory?
Guard locking for personnel protection is needed where a person could reach a hazard before it has ceased after a stop request. Assess access time, stopping time and other residual hazards. A door-position interlock alone does not hold a guard shut. Select and validate the exact locking function and any required escape or emergency release.
2) What is the difference between unique and common coding?
Coding levels and actuator teaching depend on the exact device. Individual coding can reduce the possibility of defeating an interlock with a spare actuator; it does not prevent every form of bypass. Confirm the documented coding level and additional anti-defeat measures for the installation.
3) How to cascade multiple doors?
Use only a manufacturer-approved series connection for the exact switches and controller. Assess fault masking, accumulated response time, diagnostics, supply limits and the required performance level. Where series connection is unsuitable, use separately monitored safety inputs. Do not improvise a generic output-to-input chain.
4) Which brackets for hinged vs sliding doors?
Choose mounts that preserve the specified actuator alignment throughout door travel and prevent sag, vibration or door loads from damaging the switch. Use the exact device mounting instructions. A non-contact sensor is not a substitute for guard locking where locking is required.
5) Should I choose PNP or NPN?
First establish whether the device uses safety contacts, OSSD outputs or another documented safety interface. Check the exact safety-controller input compatibility, test pulses, terminal assignment and supply. Matching PNP or NPN polarity alone does not establish safety compatibility.
6) What causes false trips and how to reduce them?
Inspect alignment, door sag, vibration, contamination, cable damage, supply and controller diagnostics using the exact manuals. Isolate hazardous energy before adjustments. Correct the cause and repeat the required functional checks; do not bypass the interlock to suppress trips.