Omron D4NA-4122 — Pin-Plunger Safety Limit Switch
SKU: D4NA-4122USD 7.00
D4N-series miniature safety limit switch, pin plunger, 1NC/1NO snap-action, M20 conduit, IP67, UL / TUV / CCC.
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Product Overview
The Omron D4NA-4122 is a member of the D4N family of miniature safety limit switches, with the top-pin plunger actuator coded 4, 1NC/1NO snap-action contacts coded 1, and the M20 single-conduit entry coded 2. The NC contact uses a forced-opening mechanism so that a contact weld will be broken mechanically on the next actuation - a requirement for PLe / Category 4 wiring when the switch is paired with a G9SA-301 or G9SP-N20S safety relay. The plastic body is rated IP67 to EN 60947-5-1, so the unit handles wet or dusty machine rooms without an extra enclosure. Pick the D4NA-4122 for guard-door interlocks, end-of-stroke stops on small cylinders, and panel-mounted position checks on light-duty machinery.
Why pin plunger rather than roller lever
The pin plunger actuator is a straight-down push with a small overtravel allowance. Choose pin plunger when the cam or dog is flat-faced and aligned squarely with the plunger axis. For cams moving side-on or at an angle, the roller-lever variants (D4N-1__ or D4N-2__) ride the cam profile without side-loading the plunger. For long overtravel with adjustable set points, the roller-lever D4N-112G is the more common pick.
Sizing the safety wiring
The D4NA-4122 is rated AC250 V 5 A / DC30 V 4 A resistive on the load side, and 500,000 electrical operations at that load. For a safety-rated Category 4 / PLe circuit, the 1NC/1NO contacts are wired into a dual-channel safety relay: the NC contact into channel 1, the NO contact into channel 2 as the cross-check loop. The relay detects single-channel failure and trips the load. Without the safety relay, the switch is a general-purpose limit switch only.
Before ordering
Confirm the conduit thread is M20 (this SKU ends in -22); the G1/2 sibling ends in -20 and the Pg13.5 in -2G. The contact form is 1NC/1NO snap-action (1); for 2NC slow-action, look at the D4N-4172 sibling. Wire to the spring-loaded M3.5 terminal screws with 0.5 to 1.5 mm stranded wire. Mount via the two M5 panel-mounting screws on 25 mm centres. Use the M12 connector variant when the wiring runs through a quick-disconnect harness.
Key Features
- D4N series miniature safety limit switch
- Top-pin plunger actuator (D4N-4122 code)
- 1NC/1NO snap-action contacts with forced opening on NC
- Single M20 conduit entry
- IP67 protection (EN 60947-5-1)
- AC250 V 5 A / DC30 V 4 A resistive contact rating
- 500,000 electrical operations min at rated load
- 15 million mechanical operations min
- Gold-plated contacts - small load compatible
- Plastic body 30 mm wide, DIN-rail or panel mount
- Operating temperature -30 to +70 degC
- UL / EN (TUV) / CCC / CSA approvals
- SKU: D4NA-4122
- Series: D4N miniature safety limit switch
Best-Fit Applications
- Guard-door interlock on a small assembly machine cabinet
- End-of-stroke limit on a pneumatic cylinder position check
- Position confirmation on a sliding panel or moving tray
- Light-duty safety circuit behind a G9SA-301 monitor relay
- Snap-action trigger for counting or basic sequencing operations
Buying Checklist
- Confirm the conduit thread is M20 - G1/2 is the -20 suffix; Pg13.5 is the -2G suffix.
- Choose the roller-lever D4N-112G when the cam or dog is angled at the actuator.
- Choose the D4N-4172 (2NC slow-action) for fail-safe dual-channel circuits that need both contacts to be NC.
- Choose the D4N-4__20 (G1/2 thread) when the cabinet gland prep is G1/2 rather than M20.
- Verify the dual-channel wiring reaches PLe / Category 4 - the safety relay (G9SA-301 or G9SP-N20S) does the cross-monitoring.
- Confirm IP67 protection is enough for the wash-down zone - the D4B heavy-duty line gives IP67 plus metal body for harsher areas.
Technical Specifications
| Series | D4N miniature safety limit switch |
|---|---|
| Actuator | Top-pin plunger (D4N-4___ code) |
| Contact Form | 1NC/1NO snap-action |
| Forced Opening | Yes on NC contact (per EN 60947-5-1) |
| Conduit | Single M20 threaded entry |
| Rated Load (Resistive) | AC250 V 5 A / DC30 V 4 A |
| Mechanical Life | 15,000,000 operations min |
| Electrical Life | 500,000 operations min at rated load |
| Operating Speed | 1 mm/s to 0.5 m/s |
| Operating Temperature | -30 to +70 degC |
| Protection Rating | IP67 (EN 60947-5-1) |
| Approvals | UL, CSA, EN (TUV), CCC |
Resources & Downloads
FAQ for D4NA-4122
What is the difference between D4NA-4122 and D4N-112G?
Both are D4N-series miniature safety limit switches. D4NA-4122 is the pin-plunger / 1NC/1NO / M20 conduit variant - the plunger is a straight-down push. D4N-112G is the roller-lever / 1NC/1NO / G1/2 conduit variant - the roller rides a side-passing cam. Use the pin plunger for flat-faced dogs aligned with the plunger axis; use the roller lever when the cam passes across the actuator.
Is the D4NA-4122 rated for Category 4 / PLe wiring?
The D4NA-4122 switch itself is approved to EN 60947-5-1 for safety use. A Category 4 / PLe circuit is achieved by wiring the two contacts through a dual-channel safety relay (G9SA-301, G9SP-N20S, or equivalent) that cross-monitors the NC and NO contacts. Without that relay, the same switch can only support lower categories.
Does the D4NA-4122 need a power supply?
No. The D4NA-4122 is a passive mechanical limit switch - the contacts open and close on plunger movement, with no external supply needed. If the LED indicator variant is fitted, the LED is fed from the load current on the load side of the contact, not a separate 24 VDC supply.
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