Omron D4NS-4BF Safety Door Switch
Omron D4NS-4BF is an M20 2NC safety door switch for monitoring protective machine doors and movable guards. Its 1-conduit construction provides an M20 wiring connection, while the slow-action 2NC contact configuration supplies 2 normally closed paths for the associated safety circuit. A Type 2 low-level coded interlock supports mechanical guard-position detection, with 10 mm minimum direct opening travel. The switch operates from 0.05 to 0.5 m/s, while IP67 protection supports industrial machine environments. The D4NS-4BF belongs to the D4NS Series within the safety interlock switch range from Omron machine safety products, connecting protective access, guard detection and safety circuit switching.

| Brand | Omron |
| Product Type | Safety Door Switch |
| Model Number | D4NS-4BF |
Omron D4NS-4BF Safety Door Switch - Technical Specifications
| Specification | Value |
|---|---|
| Type | 1-Conduit type |
| Contact configuration | Slow-action,2NC |
| Conduit outlet/Connector | M20 |
| Interlock type | Type 2 |
| Coding level | Low level coded |
| Degree of protection | IP67 |
| Operating speed | 0.05 to 0.5 m/s |
| Direct opening force | <Standard type> 60 N min.; <High pull-force type> 80 N min. |
| Direct opening travel | 10 mm min. |
| Contact resistance | 25 mΩ max. |
| Rated insulation voltage (Ui) | 300 V |
| Rated frequency | 50/60 Hz |
| Insulation resistance | 100 MΩ min. |
| Contact gap | 2 × 2 mm min |
| Vibration resistance | Malfunction: 10 to 55 Hz, 0.75 mm single amplitude |
| Shock resistance | Destruction: 1,000 m/s2 min. Malfunction: 300 m/s2 min |
| Ambient operating temperature | −30 to 70°C (with no icing) |
| Ambient operating humidity | 95% max |
| Weight | Approx. 96 g |
The Omron D4NS-4BF Safety Door Switch uses a 1-conduit M20 construction with slow-action 2NC contacts for monitoring protective machine doors and movable guards. Its 2 normally closed contacts provide safety switching paths, while the M20 conduit supports a defined machine wiring connection. A Type 2 low-level coded interlock provides mechanical guard-position detection and links actuator movement with switch operation. The direct opening mechanism supports positive contact separation, with 10 mm minimum direct opening travel. Direct opening force is 60 N minimum for standard types and 80 N minimum for high pull-force types. Operating speed ranges from 0.05 to 0.5 m/s, while IP67 enclosure protection supports industrial installations exposed to dust or moisture. The important semantic relationships are 2NC contacts, M20 conduit, safety door interlocking, machine guard detection and protective access monitoring. These functional attributes provide useful search and product-selection context without filling the page with secondary specifications. Within the D4NS family, contact arrangement is particularly useful for distinguishing otherwise similar M20 variants. The switch therefore connects mechanical guard movement with the associated machine safety circuit through normally closed contact operation. For an M20 model requiring 2NC plus 1NO switching paths, the D4NS-4CF provides the closest related configuration.


