Emergency Stop Switches / E-Stop Switches ESTOP OPERATOR
Research Notes
1. What this is
A165E-SY is an Omron A16 16mm pushbutton.
2. Part-number decode
- Series: Omron A16
- Type: pushbutton
- Panel cutout: 16mm
3. Compatibility & ordering
Omron makes industrial command switches (A22 22mm, A16 16mm — unitized, contact in the model code), illuminated pushbuttons/pilot lights (A3, M2), and a widely-used B3 PCB tactile-switch family. Match by size, function (pushbutton/selector/indicator/E-stop), colour, illumination, and contact arrangement, then use the Omron datasheet to confirm the exact colour and voltage encoded in the part number.
4. Data-quality note
The Omron series and switch type are decoded from the part number (grounded in the omron.com catalog and DigiKey listings; A22 corroborated by curated-loop work). Omron 22/16mm command switches are unitized — the contact arrangement is part of the model code — but the exact colour and voltage suffix should be confirmed against the Omron datasheet for a precise order (not guessed here).
5. Sources
- Omron product catalog (omron.com / components.omron.com)
- Distributor listing (DigiKey / Mouser) — search the exact part number
1 source
- Omron — A165E-SY — omron.com
Specifications
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Device class
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pushbutton
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Enriched by
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omron-decoder-2026-08-12
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Lead time
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0 Days
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Manufacturer series
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A16
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Mouser part number
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653-A165E-SY
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Panel cutout
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16mm
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Pn status
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decoded
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Rohs status
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RoHS Compliant
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Series description
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Omron A16-series 16mm pushbutton / illuminated pushbutton (A16L = illuminated; compact panel command switch)
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Installation Quick Reference
Panel cutout: 22mm. Mount with the yellow backing plate visible (required by EN/ISO 13850).
Wiring: Wire NC contacts in series with the safety relay input channels. Use dual-channel wiring for SIL 3 / PLe applications. Never wire directly to a motor contactor.
Testing: Press the e-stop and verify the machine stops within the required time. Test the reset mechanism. Repeat monthly per EN/ISO 13850.
Dimensions
Troubleshooting
E-stop won't reset (twist/pull doesn't release)
Check for debris in the mechanism. For twist-release: turn clockwise 45-90 degrees. For push-pull: pull straight out firmly. If the mechanism is stuck, the internal latch may be damaged — replace the entire head assembly.
Machine doesn't stop when e-stop is pressed
Critical safety issue. Immediately lock out the machine. Check wiring — NC contacts must be in series with the safety relay. Verify the safety relay is functioning. A broken wire in an NC circuit should cause a stop, so check for a wiring bypass.
Safety relay faults after e-stop reset
The safety relay detects a cross-fault between the two monitoring channels. Check that both NC contacts on the e-stop are switching simultaneously. One contact may be welded closed — replace the contact block.
Quick Specs
- Device class
- pushbutton
- Enriched by
- omron-decoder-2026-08-12
- Lead time
- 0 Days
- Manufacturer series
- A16
- Mouser part number
- 653-A165E-SY
