SICK WTB2S-2P1151 Proximity Sensor

As a W2 proximity sensor with background suppression, the WTB2S-2P1151 (part no. 1066110) reports objects that enter a fixed detection window and stays quiet for anything farther away, which suits conveyors, stackers and packaging machines. The data sheet gives a maximum sensing range of 1 mm … 150 mm (sensing range value printed as 18 mm … 110 mm). The switching output is PNP with light/dark switching, the supply is 10 V DC … 30 V DC and the connection is Cable, 4-wire, 2 m.

Background suppression on the W2 housing

A dark product and a light product at the same distance behave much more alike on a background-suppression sensor than on an energy-based one, so mixed colours on one belt are less of a problem. Keep the front screen clean: a film of dust or oil lowers the received light and shifts the effective switching point over time.

Its emitter is a PinPoint LED emitting visible red light with a spot of Ø 3.5 mm (50 mm). It is adjusted through potentiometer, 3 turns. It responds in < 0.5 ms at 1,000 Hz switching frequency.

Technical specifications

Type code WTB2S-2P1151 and part number 1066110

A label on the housing shows the type code and the part number together; use both when you compare a replacement. For WTB2S-2P1151 the part number is 1066110. Sibling types in the WTB2S family are close in appearance but not in wiring or range.

Comparable active types from the same family are:

• WTB2S-2N1151 (part no. 1066113) – Switching output: NPN
• WTB2S-2P3151 (part no. 1067502) – Connection type: Cable with male connector, Connection type Detail: Cable with connector M8, 3-pin
• WTB2S-2N1151S43 (part no. 1091234) – Switching output: NPN
• WTB2S-2N1151S26 (part no. 1116488) – Switching output: NPN
• WTB2S-2P1351S33 (part no. 1082752) – Connection type Detail: Cable, 3-wire

Mounting, wiring and set-up notes for WTB2S-2P1151

Plan for 10 V DC … 30 V DC at the terminals, IP67 enclosure protection and an operating ambient of –25 °C … +50 °C. Current draw is 20 mA. The body measures 7.7 mm x 27.5 mm x 13.5 mm. Keep spare units of the same part number on the shelf if the sensor is critical to line uptime, since a different variant may need re-wiring.

Where the WTB2S-2P1151 fits on a production line

The WTB2S-2P1151 belongs on machines where an object has to be seen at a known distance in front of the sensor while whatever lies behind it is ignored. Typical places are conveyor transfers, stacker infeed points and packaging stations, where a product passes close to the optics and a frame, guard or wall sits farther back. Because the sensor works on background suppression rather than on the amount of returned light, the switching point is tied to distance, which keeps detection steady when cartons, films and containers of different colours share the same belt. The small rectangular W2 housing is useful where space beside a guide rail or inside a machine frame is limited, and the data sheet lists the detection of small objects as a special application, which matches the narrow visible red light spot.

Selection considerations before ordering

Start with the electrical side of the existing machine. The WTB2S-2P1151 has a PNP switching output, so the PLC or relay input it feeds must be a sourcing-compatible input; where the control panel is wired for NPN signals, the NPN sibling types listed on this page are the relevant comparison instead. Next, confirm the connection style. This type uses a fixed four-wire PVC cable, while other family members use a cable with a connector, and swapping one for the other changes how the sensor is terminated in the field. Finally, check that the distance between the sensor face and the target sits comfortably inside the adjustable sensing range rather than at its edge, and that light or dark switching is set to match the logic the control program expects.

Integration with the control system

On most lines the sensor output goes straight to a PLC digital input, a counter or an interposing relay. Its fast response and high switching frequency make it suitable for counting and for presence checks on moving product, but the receiving input and the program scan still need to be quick enough to catch short pulses. Route the cable away from motor leads and drive output cables, and keep the supply within the stated DC range so that ripple does not disturb the output.

Installation and operation in Oman and GCC sites

Plants across Oman and the wider GCC often combine high ambient heat, airborne dust and, near the coast, humid salty air. The IP67 enclosure rating helps against dust and water, but the sensor should still be placed out of direct sun and away from hot surfaces, because the operating temperature range on the data sheet is the limit that counts. Dust settling on the optics is the most common cause of drift on desert and cement-area sites, so add a cleaning check of the front screen to routine maintenance and re-check the potentiometer setting after any mechanical change to the mounting. When a unit is replaced, set the new sensor with the actual product in position rather than copying the old adjustment by eye.

Documents and quotation

We attach SICK’s own data sheet for part no. 1066110 (WTB2S-2P1151) as an unaltered PDF; use it to compare dimensions, connections and ratings with the device on your machine. Send the type code and part number with quantity and delivery location through the RFQ form and we will quote. Related items are listed under Sensors & Transmitters. Please verify the variant against the nameplate of the device you are replacing, since similar types differ in small details. The data sheet is the authority.