Omron D4B-4111N — Safety Limit Switch, 1NC/1NO, Roller Lever
SKU: D4B-4111NUSD 22.00
Aluminum-body safety limit switch with 1NC/1NO snap-action contacts, resin roller lever actuator, M20 conduit, direct opening mechanism, 4 A 250 VAC, IP67, -40 to +80 °C operating range. Certified EN 60947-5-1.
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Product Overview
The D4B-4111N is the resin-roller-lever variant of Omron's D4B-@N safety limit switch family — a robust aluminum die-cast housing with a direct-opening mechanism (DOM) and 1NC/1NO snap-action contacts, suitable for industrial guard-door interlock applications up to Cat 1 / PL c. The aluminum housing stands up to mechanical impact, oil splash, and outdoor weather where the plastic-body D4N series would fail. The direct-opening mechanism means the NC contact is mechanically forced open when the actuator is withdrawn — even if the contact is welded closed by an over-current fault, the next mechanical operation will positively break the circuit.
Decoding the D4B-4111N model number
The D4B-@N model code: D4B = D4B series safety limit switch (aluminum body); 4 = contact arrangement '1NC / 1NO snap-action' (vs 1 = 1NC slow-action, 2 = 2NC slow-action, 5 = 1NC snap-action, etc.); 1 = snap-action mode (vs 2 = slow-action with same contacts); 1 = roller-lever actuator type (vs 0 = plain plunger, 2 = plain roller, 3 = cross-roller, etc.); 1 = general-purpose lever (vs 7 = adjustable-length lever, 9 = long lever); N = conduit size M20 with screw terminals (other variants: A = G1/2 conduit, B = PG13.5 conduit, C = M12 connector). Common variant pairings: D4B-4111N (this SKU, M20), D4B-4111A (G1/2), D4B-2111N (2NC, M20), D4B-4511N (same with stainless lever).
Direct opening mechanism (DOM) — required for Cat 1 / PL c
The D4B-@N family has a certified direct-opening mechanism (DOM) per EN 60947-5-1 — the NC contact is mechanically linked to the actuator lever such that if the actuator is forcibly withdrawn, the contact MUST open even if the contact has welded closed by a fault. The DOM provides 20 N minimum direct-opening force and 50° minimum direct-opening travel — verified by TÜV SÜD during certification. This positive-break capability is the key feature that allows the D4B-@N to be used in personnel-protection safety chains where a stuck contact could be deadly (e.g., robotic-cell guard door).
Aluminum housing vs plastic D4N
The aluminum die-cast housing of the D4B-4111N handles environments that plastic-body D4N series cannot: (1) mechanical impact on a moving guard or machine-tool fixture — the aluminum body resists denting at 10 J impact; (2) outdoor installations (valve actuators, outdoor cabinet doors) where UV degradation of plastic is a concern — the aluminum body is unaffected; (3) high-temperature environments up to +80 °C (D4N plastic is limited to +70 °C); (4) cold climates down to -40 °C (D4N plastic is limited to -30 °C).
Key Features
- Heavy-duty aluminum die-cast housing
- 1NC / 1NO snap-action contact configuration
- Direct opening mechanism certified per EN 60947-5-1
- 20 N minimum direct-opening force, 50° minimum direct-opening travel
- TÜV SÜD certified for use in Cat 1 / PL c safety chains
- Resin roller lever actuator
- M20 × 1.5 conduit entry for armored cable or cable gland
- Screw terminals with self-lifting clamps
- SKU: D4B-4111N
- Series: D4B-@N Safety Limit Switch (aluminum body, direct-opening)
- Voltage: 250 VAC
Best-Fit Applications
- Robotic-cell guard door interlock — D4B-4111N mounted on the door frame with the lever actuated by the closed door; NC.
- Conveyor section guard — D4B-4111N at each conveyor-access panel, NC contact wired in series to a Cat 3 G9SB-200-B safety.
- Outdoor cabinet door position — D4B-4111N aluminum body handles outdoor weather better than plastic D4N, NC contact signals intrusion or.
- Heavy-machine-tool guard interlock — D4B-4111N's high mechanical life handles the constant door cycling of a production machine
Buying Checklist
- Pick D4B-4111N for aluminum-body 1NC/1NO snap-action safety limit switch with roller lever and M20 conduit
- Pick D4B-4111A if you have a G1/2 conduit on your existing wiring
- Pick D4B-2111N for 2NC slow-action — pick for dual-state light-curtain reset logic
- Pick D4B-4511N for stainless steel lever — pick for high-temperature or food-grade stainless requirements
- Pick D4N-112G if plastic-body is acceptable and you need a lighter switch for a small machine
- Pick D4NS-1AF for plastic tongue-operated safety door switch
Technical Specifications
| Model | D4B-4111N |
|---|---|
| Series | D4B-@N Safety Limit Switch (aluminum body, direct-opening) |
| Type | Safety limit switch with roller lever, snap-action |
| Contact Configuration | 1NC / 1NO (snap-action) |
| Snap-Action Characteristic | < 5 ms transfer time once operating point reached |
| Direct Opening Mechanism | Certified per EN 60947-5-1 (force-guided contacts) |
| Direct Opening Force | 20 N min |
| Direct Opening Travel | 50° min |
| Actuator Type | Resin roller lever (R14 roller, 14 mm dia) |
| Rated Voltage | 250 VAC max / 30 VDC max |
| Rated Current | 4 A resistive, 3 A inductive (AC-15) |
| Operating Temperature | -40 to +80 °C (no icing) |
| Certifications | CE, cULus listed, TÜV SÜD EN 60947-5-1 |
Resources & Downloads
FAQ for D4B-4111N
What does "direct opening mechanism (DOM)" mean on the D4B-4111N?
Direct-opening mechanism (DOM) means the NC contact is mechanically linked to the actuator in such a way that if the actuator is forcibly withdrawn, the NC contact MUST open — even if the contact has welded closed due to over-current or contact failure. Without DOM, a stuck contact would prevent the safety system from detecting guard-open. With DOM, the next mechanical operation of the actuator (e.g., opening the guard) guarantees the NC contact breaks.
Can the D4B-4111N be used for Cat 4 / PL e safety?
The D4B-4111N is suitable for Cat 1 / PL c as a single switch in a single-channel safety chain.
How is the D4B-4111N different from the D4N-112G?
Both are 1NC/1NO safety limit switches with direct-opening mechanism — the difference is housing material. The D4B-4111N has an aluminum die-cast housing (better mechanical impact resistance, wider temperature range -40 to +80 °C, suitable for outdoor use); the D4N-112G has a plastic housing (lighter weight ~80 g vs ~250 g, suitable for indoor use, limited to -30 to +70 °C). For indoor machines with low mechanical impact (most assembly machines, packaging equipment, light conveyors), the D4N-112G is the cost-effective pick.
How do I wire the D4B-4111N to a safety relay?
The D4B-4111N has a 1NC / 1NO snap-action contact set, accessible via screw terminals in the M20 conduit housing. Wire the NC contact (typically terminal 1-2) to the safety relay's input channel (e.g., T11-T12 on a G9SE-201), and the NO contact (typically terminal 3-4) is typically used for monitoring (feedback loop to the safety relay's EDM input to confirm the relay's contactors drop out before re-energizing).
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