Every SICK sensor part number tells a story — family, housing, output, and connector all live inside a short alphanumeric string. Identifying a SICK sensor part number correctly remains one of the most common challenges in industrial maintenance. Moreover, with over a thousand active product families, a single character on a label can decide whether a replacement restores production in minutes or stalls a line for days.
This guide explains how to read a SICK sensor part number, how to verify authenticity, and how to specify replacements when the original code becomes obsolete [1].
SICK sensor part number overview
SICK AG, a German manufacturer of industrial sensors, operates from its headquarters in Waldkirch. Its product range spans photoelectric, inductive, ultrasonic, capacitive, vision, encoder, and safety devices.
Every SICK sensor carries two identifiers: first, a human-readable type code, and second, a 7-digit order number.
Typical industries include automotive, packaging, logistics, food and beverage, as well as semiconductor manufacturing.
What is a SICK sensor part number?
A SICK sensor part number has two parts. First, the type code provides a descriptive string such as WL12-3P2431. Second, the 7-digit order number, for example 1041453, identifies the catalog entry.
The type code describes the sensor family, housing, output, and connection. In contrast, the order number serves as a unique catalog reference for ordering, warranty registration, and firmware lookups.
Type code structure
The type code reads left to right: family prefix, housing series, output type, and feature suffix.
For example, in WL12-3P2431, “WL” denotes a photoelectric retro-reflective sensor. Next, “12” indicates the housing series. After that, “3P” specifies a PNP output. Finally, the last digits encode range, connector, and adjustment options.
Order number structure
The 7-digit order number runs sequentially and carries no embedded meaning.
Nevertheless, it acts as the definitive identifier for SICK’s logistics and service systems. Therefore, engineers should always reference it when contacting technical support or requesting a quotation.
Why correct SICK sensor part number identification matters
Misidentifying a SICK sensor part number can introduce subtle failures that prove difficult to diagnose.
For instance, two units with nearly identical type codes may differ in output polarity, light-on/dark-on switching, or connector pinout.
As a result, a PNP unit in a circuit expecting NPN will not switch a load. Similarly, a sensor with M12 4-pin wiring substituted for an M8 3-pin variant will not mate with the existing harness.
Operational risk
In safety-rated applications, installing a non-equivalent sensor can invalidate the machine’s risk assessment.
Furthermore, light curtains, safety laser scanners, and safety encoders carry specific performance level (PL) and safety integrity level (SIL) ratings tied to the exact part number.
Consequently, substituting a visually similar but uncertified unit creates compliance and liability exposure.
When to decode a SICK sensor part number
Decoding becomes necessary in several recurring scenarios.
First, a label may wear partially, leaving only fragments of the type code visible. Alternatively, a sensor may have been discontinued, and an engineer must specify a successor.
In other cases, a procurement team needs to verify that a quoted part matches the original requisition. Additionally, a maintenance technician may suspect a counterfeit unit was installed during a previous repair. When a verified replacement is needed, you can browse current SICK sensor inventory at Enicstra.
Key SICK product families
Photoelectric sensors
Photoelectric SICK sensor part numbers begin with prefixes including WL (retro-reflective), WT (diffuse), WS/WE (through-beam pair), WTB (BluePilot diffuse), and GTB6 (compact diffuse).
These cover ranges from a few millimeters to over 50 meters. As a result, they form the most frequently replaced category in industrial maintenance.
Inductive and capacitive sensors
Inductive proximity sensors carry the IME, IMB, or IQ prefix. In turn, they detect ferrous and non-ferrous metals.
Capacitive variants, by contrast, use CM or CQ prefixes. They respond to liquids, granulates, and non-metallic targets.
Typically, the numeric portion encodes barrel diameter (M8, M12, M18, M30) and sensing distance.
Ultrasonic sensors
Engineers use ultrasonic models such as UM30, UM18, and UC30 where optical detection proves unreliable.
For example, this includes targets that appear transparent, color-varying, or surrounded by steam.
In addition, the type code identifies blind zone, maximum range, and output mode (analog 4–20 mA, switching, or IO-Link).
Vision and code readers
The CLV, ICR, Lector, and InspectorP families cover 1D, 2D, and image-based identification.
However, decoding these part numbers requires attention to resolution, focal distance, and integrated lighting variants. All of these factors appear in the type code suffix.
Safety and measurement
Safety laser scanners include microScan3, nanoScan3, and S300. Similarly, safety light curtains include deTec and C4000.
Distance sensors, meanwhile, include LMS, DT, and DL series.
Importantly, each carries application-specific certifications that engineers must match exactly when replacing.
SICK sensor part number diagnostics and verification
Before installing a replacement, engineers should cross-check the part against three independent sources.
First, the SICK Product Finder accepts both type code and order number and returns the current datasheet [1].
Second, the printed label on the sensor body must match the etched serial on the housing. Otherwise, a mismatch strongly indicates refurbishment or counterfeiting.
Third, the firmware version reported via IO-Link or the configuration software should align with the documented release for that order number.
Engineering considerations
When specifying a replacement, engineers must confirm several parameters against the original installation.
These include supply voltage (typically 10–30 V DC), output type (PNP, NPN, push-pull, analog, or IO-Link), switching frequency, ambient temperature range, enclosure rating (IP65, IP67, IP69K), and connector style.
Fortunately, SICK’s datasheets list these parameters in a standardized table for every order number [2].
Technical specifications reference
Most SICK sensors operate from a 24 V DC supply. Typically, current draw ranges between 20 mA and 200 mA.
Switching outputs handle 100 mA continuous load with built-in short-circuit protection.
Furthermore, response times range from 0.5 ms for high-speed photoelectric devices to 30 ms for ultrasonic and safety units.
Enclosure materials usually include PBT, ABS, or nickel-plated brass for inductive barrels.
Typical applications
Packaging and material handling
Retro-reflective and diffuse photoelectric sensors detect cartons, bottles, and pallets on conveyors.
Consequently, part numbers in the WL12, WL27, and W18 series rank among the most common replacements in this segment.
Automotive assembly
Inductive sensors (IME, IQ) confirm fixture presence and tool position.
In addition, safety scanners such as microScan3 protect robotic cells.
Meanwhile, vision systems like Lector and InspectorP verify VIN plates and component orientation.
Logistics and intralogistics
Distance sensors (LMS, DT50) provide volumetric measurement on dimensioning systems.
Similarly, code readers (CLV, Lector) drive sortation at speeds exceeding 2 m/s.
Food and beverage
Hygienic-rated variants with IP69K enclosures and stainless housings carry suffixes such as “-S01” or family designations including the W4 Hygiene line.
Installation considerations
Generally, mechanical fit rarely limits SICK sensor replacement, because housing dimensions stay consistent within a family.
Instead, the critical points include alignment of the optical axis for through-beam and retro-reflective devices, correct teach-in for diffuse and ultrasonic units, and verification of the switching output before the line returns to service.
For reference, SICK provides detailed mounting instructions and minimum clearances in each operating manual [3].
Common SICK sensor part number challenges
Obsolete part numbers
SICK publishes successor recommendations for discontinued products through its lifecycle status portal.
Typically, a part marked “Phase-out” remains available for a defined period. However, a “Discontinued” part requires a documented migration to a successor family.
Therefore, direct substitution without consulting the migration note can result in changed pinouts or output behavior.
Counterfeit and refurbished units
Indicators of non-authentic product include inconsistent laser etching, missing country-of-origin marking, blurred labels, and absence of the holographic security feature on safety devices.
When authenticity remains in doubt, SICK customer service can verify the serial number [4].
Partial or damaged labels
When the label becomes illegible, the 7-digit order number printed on the side of the housing or on the connector cap often remains readable.
Fortunately, this number alone suffices to retrieve the full specification from SICK’s catalog system.
Compatibility and cross-referencing
Generally, cross-referencing between SICK sensor part numbers stays straightforward within a sensing principle. However, engineers should never assume compatibility across principles.
For example, a WL retro-reflective sensor cannot replace a WT diffuse unit without re-engineering the application, even if the housing and connector appear identical.
Therefore, third-party cross-reference tables should serve only as starting points, and engineers must validate them against the original SICK datasheet.
Operational advantages of accurate identification
Maintaining accurate SICK sensor part number records reduces unplanned downtime.
In addition, it prevents the introduction of non-compliant safety components and shortens the diagnostic cycle when intermittent faults occur.
Finally, a well-maintained sensor inventory referenced by both type code and order number simplifies audits and warranty claims.
Conclusion
SICK sensor part numbers reveal their structure once engineers understand the format.
As a result, engineers who routinely decode the type code, verify the 7-digit order number against the manufacturer’s catalog, and inspect for authenticity markers can specify replacements with confidence.
For obsolete, discontinued, or hard-to-source SICK sensors, the Enicstra Sourcing Team maintains an extensive inventory of new and surplus units across the photoelectric, inductive, ultrasonic, vision, and safety ranges, supporting verification and cross-referencing for industrial maintenance teams.
References
- SICK AG, Product Finder, https://www.sick.com/us/en/product-finder/
- SICK AG, Operating Instructions and Datasheets, https://www.sick.com/us/en/downloads/
- SICK AG, Mounting and Installation Guidelines, https://www.sick.com/us/en/support/
- SICK AG, Product Authenticity Information, https://www.sick.com/us/en/company/
Article prepared by the Enicstra Sourcing Team.