Omron Limit & Basic Switches — EE-S, D4C, SS-5Q
Two different switch technologies sit under this heading and they are not interchangeable. D4C and SS-5Q are mechanical limit switches with a plunger or lever actuator. The EE-S family is a slotted optical switch — a photomicrosensor with a slot and an internal LED and phototransistor, no mechanical contact at all. Order the right one for the actuator you actually have.
Lifecycle status
EE-S is current; parts of D4C and SS are end-of-life with no replacement offered
Omron's discontinuation database records "D4C series, some products" as ended 31 March 2025 and an earlier "compact D4C limit switch" group as ended 31 March 2023, both with no replacement listed. It separately publishes a dated mapping of nine D4C models ending 29 February 2024 onto lower-numbered replacements such as D4C-4401 to D4C-4201. For SS it records "some SS models" as ended 31 March 2023 with no replacement. The EE-SX slotted optical range is not on the discontinuation list and EE-SX and EE-SA parts are stocked as active across major distributors.
What to fit instead: D4C-44xx map to D4C-42xx, 45xx to 43xx; other discontinued D4C and SS parts have none
Key specifications
- D4C-1202 roller plunger: SPDT snap action, 5 A at 250 VAC / 4 A at 30 VDC resistive, IP67, die-cast metal housing, mechanical life 10 million operations
- D4C actuator digit: 1201 pin plunger, 1202 roller plunger, 1203 cross-roller, 1210 bevel, 1220 roller lever, 1241 and 1242 panel mount, 1250 plastic rod, 1260 centre roller lever
- EE-SX is a photomicrosensor: output is a phototransistor or Schmitt-trigger transistor, not a mechanical NO/NC contact, and it needs no actuator at all
- EE-SX shape digit: 0 standard, 1 L-type, 2 T-slot 7 mm, 3 and 4 compact, 5 T-slot 10 mm, 6 F-type, 7 R-type
- EE-SX output digit: blank or A for NPN light-on / dark-on, P or R for PNP; WR means pre-wired, C1J the relay variant
- Mounting is by the supplied bracket or a threaded hole — these are panel-mount devices, unlike the barrel-mount E2B and E2E inductive sensors
How to read a D4C or EE-SX model number
Confirm the technology before the digits. A D4C takes an actuator; an EE-SX takes a flag or lever entering a slot.
| Element | Meaning | Example |
|---|---|---|
| D4C-1202 | Standard body, roller plunger | 1201 pin, 1202 roller, 1203 cross-roller |
| D4C-1220 | Roller lever actuator | High-travel lever variants |
| EE-SX670 | Standard slotted optical switch | 6 = operation mode, 7 = R-type body |
| EE-SX671-WR | R-type body, pre-wired | WR replaces the connector with a cable |
| EE-SX772A | T-slot 10 mm, NPN dark-on | A output variant |
| EE-SX870 | F-type compact body | 0 = standard shape |
Omron does not publish a complete digit-by-digit legend for the EE-X range, so we do not publish one. The EE-SX legend above is Omron's own naming FAQ.
Where these parts get used
- Cylinder end-of-travel detection on a pneumatic axis where a mechanical roller plunger on the piston rod is the simplest reliable signal
- Panel-door and machine-guard monitoring with a slotted optical switch, where a non-contact sensor avoids wear on a frequently operated door
- Legacy CS1 and C200H machine retrofits where the original D4C or SS switch has failed and the actuator type must be matched exactly
Which model do you need
- Choose D4C for a mechanical actuator and EE-SX for a flag or lever in a slot — they are different technologies and neither substitutes for the other.
- On D4C, match the actuator digit to what is physically on the machine: roller plunger and pin plunger actuate differently.
- Check the D4C model against Omron's replacement mapping before ordering, because parts of the range are end-of-life with no replacement.
- Choose EE-SX with the WR suffix for pre-wired cable if your panel does not use connectors.
All 24 Omron Limit & Basic Switches SKUs
Every part number below links to its own page with full specifications, compatibility notes and stock status.
Frequently asked
What is the difference between a D4C and an EE-SX?
A D4C is a mechanical limit switch with a plunger or lever actuator and a snap-action SPDT contact rated 5 A at 250 VAC. An EE-SX is a slotted optical switch — a photomicrosensor with an internal LED and phototransistor, with no moving parts and no mechanical contact. They sense different things and are not interchangeable.
What does D4C-1202 mean?
The D4C series in the standard die-cast housing with a roller plunger actuator, SPDT snap action, IP67, 5 A at 250 VAC resistive, operating force 450 gf and 10 million mechanical operations. The 12xx family denotes body size, and the final digits give the actuator type.
Is the EE-SX an optical switch or a mechanical one?
Optical. The EE-S family is a photomicrosensor: an LED and a phototransistor face each other across a slot, and the flag or lever entering the slot blocks the beam. The output is a phototransistor or Schmitt-trigger transistor, which is why the WR and output-letter suffixes describe polarity and light-on/dark-on behaviour rather than NO/NC contacts.
Is the SS-5Q still current?
Omron records 'some SS models' as discontinued on 31 March 2023 with no replacement offered, but does not publish which specific models are affected, so we cannot confirm whether SS-5GL13 specifically is affected. If you need this part, confirm current status with us before ordering.
What replaces a D4C-4401?
Omron's discontinuation mapping sends the D4C-44xx group to the D4C-42xx range — D4C-4401 to D4C-4201, 4402 to 4202, 4420 to 4220 and so on — with effect from 29 February 2024. Confirm the replacement's actuator type matches before substituting.
Specification sources
Specifications on this page were checked against Omron's own documentation. If a figure here disagrees with your datasheet, the datasheet wins — tell us and we will correct it.
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