In many factories and automated systems, there comes a point when a simple on/off photoelectric sensor is no longer enough. You need real distance information, not just a detection signal. That’s exactly where the SICK WTA24-P5401 infrared distance sensor earned its place in countless applications over the years. Even though this model is now discontinued, thousands of engineers still maintain machines that rely on it, and many others look for suitable replacements with similar capabilities.
This blog explores what the SICK WTA24-P5401 infrared distance sensor is, how it works, its technical specifications, typical applications, and what you can consider as modern alternatives. Whether you are troubleshooting an existing installation or designing a new system around a similar mid-range distance sensor, understanding the strengths and limits of the WTA24-P5401 will help you make smarter engineering decisions.
What is the SICK WTA24-P5401 infrared distance sensor?
At its core, the SICK WTA24-P5401 infrared distance sensor is a compact, non-contact distance measuring device designed for industrial automation. Unlike a conventional photoelectric sensor that only tells you if an object is present or not, this unit provides both an analog 4–20 mA distance output and two discrete PNP switching outputs.
The operating principle of the SICK WTA24-P5401 infrared distance sensor is optical triangulation distance measurement. An infrared LED projects light onto a target, and the reflected light is received by an internal position-sensitive detector. The angle of the returned light changes with distance, and the electronics convert this into a proportional analog signal. This gives you a measurable distance instead of just a binary signal.
For this specific model, the measurable range is approximately 600 mm to 1,200 mm. Inside that window, the SICK WTA24-P5401 infrared distance sensor maps 4 mA to the near end and 20 mA to the far end. If the object moves closer than around 600 mm, the analog output falls below the normal range (around 3 mA), and if the object moves beyond 1,200 mm, the signal rises above 20 mA (around 21 mA), acting as a convenient under-range and over-range indication.
Physically, the SICK WTA24-P5401 infrared distance sensor uses a rugged zinc die-cast housing with an IP67 rating. It is built to survive shock, vibration, dust, and moisture in harsh factory environments. A standard 5-pin M12 connector (PNP, 12–30 VDC operation) makes it simple to wire into industrial control panels and PLC systems.
Key specifications of the SICK WTA24-P5401 infrared distance sensor
Before you choose or replace a sensor, it’s important to understand the core specifications. Below is a practical overview of the most important parameters of the SICK WTA24-P5401 infrared distance sensor.
Measuring range and analog output
The SICK WTA24-P5401 infrared distance sensor is a mid-range model in the WTA24 family, designed for a working range of 600–1,200 mm (about 24–47 inches). Within this range:
- 4 mA ≈ 600 mm
- 20 mA ≈ 1,200 mm
- < 4 mA → object too close (under-range)
- 20 mA → object too far (over-range)
This linear 4–20 mA output lets you scale the SICK WTA24-P5401 infrared distance sensor directly into a PLC analog input or a display device. Control systems can then convert the current to a distance value or a level percentage, depending on the application.
PNP switching outputs (Q1, Q2)
A key advantage of the SICK WTA24-P5401 infrared distance sensor is the inclusion of two PNP switching outputs (Q1 and Q2) in the same device. These outputs can be configured as:
- Simple presence detection
- Minimum and maximum limit switches
- Window or band monitoring (distance between two setpoints)
Each output of the SICK WTA24-P5401 infrared distance sensor can typically handle up to 100 mA and is short-circuit protected. In practice, many engineers use the analog output for closed-loop control, while the PNP outputs provide alarm thresholds or interlocks.
Optical characteristics and accuracy
The SICK WTA24-P5401 infrared distance sensor uses a non-visible infrared LED, typically around 880 nm, as its light source. The light spot grows from roughly 15 mm at the near end of the measuring range to about 30 mm at the far end. Internally, triangulation optics and an ASIC evaluate the position of the reflected spot to determine distance.
One of the strengths of the SICK WTA24-P5401 infrared distance sensor is its built-in background suppression and relative independence from target color. A white, high-reflectance target (around 90% reflectivity) and a very dark target (around 6% reflectivity) can be measured within a few percent of each other. Typical accuracy might be in the range of ±3% for a white target and ±8% for a black one. For many industrial applications, this is more than adequate for reliable positioning, level measurement, and diameter monitoring.
Repeatability of the SICK WTA24-P5401 infrared distance sensor is better than its absolute accuracy. Under stable conditions, the sensor tends to reproduce readings with a variation of around ±1–2% of the measured value. That means if a target stays at the same distance, the analog output will remain reasonably stable, which is essential for closed-loop control.
Response time and update rate
The response time of the SICK WTA24-P5401 infrared distance sensor is approximately 50 ms, corresponding to an update rate of about 10–20 Hz. This is a balanced setting that smooths out noise yet remains fast enough for typical industrial processes.
In practice, the SICK WTA24-P5401 infrared distance sensor is well suited to applications where objects move at moderate speeds, such as conveyor lines, level changes in bins, or gradual diameter changes on a roll. It is not designed as an ultra-fast displacement sensor for high-speed, high-frequency measurements, but it is more than capable for general automation tasks.
Environmental and electrical ratings
From an environmental standpoint, the SICK WTA24-P5401 infrared distance sensor is rated IP67. This means it is dust-tight and protected against temporary immersion in water. The operating temperature range is typically –10 °C to +55 °C, making it suitable for many indoor and some outdoor applications when properly protected.
Electrically, the SICK WTA24-P5401 infrared distance sensor operates from a 12–30 VDC supply, with reverse-polarity protection and short-circuit protected outputs. It is designed to meet common industrial EMC and low-voltage directives and typically carries CE conformity and VDE protection class II. In many installations, you will also find it used in regions that require UL or CSA compliance.
How the SICK WTA24-P5401 infrared distance sensor works in real applications
Understanding the operating principle of the SICK WTA24-P5401 infrared distance sensor helps you apply it correctly and interpret its signals. The device uses diffuse triangulation without the need for a reflector. Here’s how it works in practice:
- The infrared LED in the SICK WTA24-P5401 infrared distance sensor emits a light beam toward the target surface.
- The target reflects some of this light back toward the sensor.
- The reflected beam is focused by the optics onto a position-sensitive detector.
- As the distance to the target changes, the angle of the reflected light changes, shifting the position of the light spot on the detector.
- The electronics convert this position shift into a distance value, which is then translated into the 4–20 mA analog signal.
Because the SICK WTA24-P5401 infrared distance sensor uses angle, not just intensity, it can suppress background objects beyond the measuring range. A distant background produces a reflection at a different angle that does not fall into the active region of the detector. This is why the sensor can look toward a wall or machine structure and still correctly measure only objects within its defined 600–1,200 mm window.
For best results, the target should present a reasonably diffuse surface. Extremely shiny, mirror-like surfaces can cause specular reflections that may mislead the SICK WTA24-P5401 infrared distance sensor. In such cases, slightly tilting the sensor or the target, or using a less reflective patch, can greatly improve measurement stability.
Wiring and mounting the SICK WTA24-P5401 infrared distance sensor
Getting the most out of the SICK WTA24-P5401 infrared distance sensor starts with correct wiring and secure mounting. The sensor uses a 5-pin M12 connector, with typical pin assignments as follows:
- Pin 1 (brown): +12–30 VDC supply
- Pin 3 (blue): 0 V (ground)
- Pin 4 (black): PNP switching output Q1
- Pin 2 (white): PNP switching output Q2
- Pin 5 (gray): 4–20 mA analog output
This standard pinout makes it straightforward to integrate the SICK WTA24-P5401 infrared distance sensor with PLC input cards, analog modules, and indicator displays. Many engineers run Q1 and Q2 to digital inputs for alarms or interlocks, while the analog output feeds a 4–20 mA analog channel monitoring distance or level.
Mechanical mounting
The housing of the SICK WTA24-P5401 infrared distance sensor measures roughly 27 × 87.5 × 65 mm and includes threaded mounting holes or slots. It can be mounted directly on machine frames or equipment brackets.
SICK also offered dedicated brackets such as the BEF-WN-W24 mounting bracket and protective housings for the WTA24 family. These accessories make it easy to mount the SICK WTA24-P5401 infrared distance sensor in front-facing or side-facing orientations. When used in dusty or outdoor environments, additional protective hoods can help keep the lens clean and shield the sensor from direct impacts.
When positioning the SICK WTA24-P5401 infrared distance sensor, consider:
- The target distance should lie comfortably within the 600–1,200 mm range.
- The beam should strike the target at a consistent angle.
- The field of view should be free of obstructions that might intermittently block the light.
- Shiny backgrounds should be angled or shielded to avoid unwanted reflections.
Once physically installed, you can use the internal teach-in or adjustment process to set the switching thresholds. Typically, you place the target at the desired distance and adjust the sensor until the status LED indicates the threshold has been stored. This allows you to tailor the SICK WTA24-P5401 infrared distance sensor to your specific min/max or window limits.
Typical applications of the SICK WTA24-P5401 infrared distance sensor
The versatility of the SICK WTA24-P5401 infrared distance sensor is one reason it became a popular choice in many automation projects. Here are some of the most common use cases where this sensor has proven its value.
Profile and dimension measurement
In conveyor-based production lines, the SICK WTA24-P5401 infrared distance sensor is often mounted above or beside products to measure height, position, or profile. As each part passes through the measuring zone, the sensor’s analog output provides an instantaneous distance reading.
For example, it can check whether boxes on a conveyor stay within an allowed height window. The PNP outputs of the SICK WTA24-P5401 infrared distance sensor can then trigger rejection if a box is too tall or too short, while the analog signal provides data for quality tracking and process optimization.
Coil and roll diameter monitoring
In steel, paper, or film processing, knowing the current diameter of a coil is essential for material control and changeover planning. Mounted at a fixed distance from the coil core, the SICK WTA24-P5401 infrared distance sensor continuously measures the distance to the outer surface.
As the roll grows or shrinks, the analog output of the SICK WTA24-P5401 infrared distance sensor changes proportionally. With a simple geometric calculation in the PLC, you can convert that distance into real-time diameter, remaining material length, or percentage of roll used.
Level measurement in bins and hoppers
In shallow bins, hoppers, or small silos with depths within roughly 1 meter, the SICK WTA24-P5401 infrared distance sensor can serve as a non-contact level transmitter. Mounted above the material, it measures the distance to the surface of bulk solids or liquids.
The analog output of the SICK WTA24-P5401 infrared distance sensor is easily scaled to represent percentage level, while Q1 and Q2 can act as minimum and maximum level alarms. Because the sensor is rated IP67 and uses a robust housing, it handles dusty environments well, especially when paired with a lens shield or occasional air purging.
Positioning in warehousing and handling systems
Automated storage and retrieval systems (AS/RS), gantry cranes, and shuttle systems often require precise but not ultra-high-speed distance feedback. The SICK WTA24-P5401 infrared distance sensor can measure how far a carriage, fork, or hoist is from a reference point, such as the floor or a stop beam.
By feeding the 4–20 mA signal from the SICK WTA24-P5401 infrared distance sensor into the control system, you can implement smooth, consistent approaches to pallets, shelves, or docking positions. The PNP outputs can be set at critical thresholds to ensure safe stopping zones or confirm correct positioning.
Web loop and sag control
In web handling applications—such as paper, textiles, plastic film, or metal strip—it is often necessary to control loop sag or tension. Mounted above a festoon loop, the SICK WTA24-P5401 infrared distance sensor monitors loop depth and provides a continuous distance signal.
The control system uses the analog output of the SICK WTA24-P5401 infrared distance sensor to adjust motor speeds and maintain a stable loop. In more advanced systems, two sensors can be used at the edges of a web to detect uneven sag, helping prevent wrinkles, stretching, or tears.
General automation upgrades
Whenever plant engineers wanted to move beyond simple presence detection and gain richer information about position or level, the SICK WTA24-P5401 infrared distance sensor was a natural upgrade. From detecting forklift fork height to monitoring gate positions or measuring deflection of a machine part under load, it brought analog feedback into systems that previously relied only on on/off sensors.
Alternatives and successor models to the SICK WTA24-P5401 infrared distance sensor
Although the SICK WTA24-P5401 infrared distance sensor is discontinued, its concept lives on in many modern devices. If you are maintaining an existing installation or designing a new one, it helps to know what alternatives and successors are available.
Other WTA24 series models
Within the same family, there are related models that share the same housing and basic design as the SICK WTA24-P5401 infrared distance sensor but offer different measuring ranges:
- WTA24-P5201: Shorter range, roughly 250–350 mm, with higher resolution and faster response.
- WTA24-P5501: Longer range, roughly 1,000–3,000 mm, with a slower but stable update rate.
- WTA24-P5201 S04: A special variant covering around 100–500 mm.
All these units operate on the same triangulation principle and can often be used as substitutes where the exact range of the SICK WTA24-P5401 infrared distance sensor is not critical, provided you re-scale your analog inputs and adjust your mounting location.
Modern SICK distance sensor families
To replace the SICK WTA24-P5401 infrared distance sensor with a current product, many engineers look at SICK’s newer distance sensor lines. Popular choices include:
- DT20 / DT10: Compact analog distance sensors for shorter to mid-range distances.
- DT50 / Dx50: Time-of-flight distance sensors with 4–20 mA outputs and switch outputs, covering ranges far beyond the original WTA24 family.
- OD series: High-precision optical displacement sensors for applications that need finer resolution than the SICK WTA24-P5401 infrared distance sensor.
- Ultrasonic families (UC30, UC4, etc.): For applications where target color and reflectivity are highly variable and speed demands are moderate.
These modern sensors often come with additional features such as IO-Link communication, advanced configuration tools, and better temperature compensation. When replacing a SICK WTA24-P5401 infrared distance sensor, it is important to match key parameters like range, accuracy, update rate, and output types.
Cross-brand alternatives
If you are open to other manufacturers, there are many sensors that can fulfill the same role as the SICK WTA24-P5401 infrared distance sensor. Vendors like Banner Engineering, Keyence, Pepperl+Fuchs, and Baumer offer both optical and ultrasonic distance sensors with 4–20 mA outputs and switch outputs.
The main selection criteria remain the same:
- Required measuring range and blind zone
- Desired accuracy and repeatability
- Response time
- Output types (analog, PNP, NPN, IO-Link, etc.)
- Environmental ratings and housing style
By comparing these parameters to those of the SICK WTA24-P5401 infrared distance sensor, you can choose an appropriate modern sensor that fits both your control system and mechanical layout.
Related product collections for the SICK WTA24-P5401 infrared distance sensor
If you’re exploring, maintaining, or upgrading applications built around the SICK WTA24-P5401 infrared distance sensor, it often makes sense to review compatible and alternative products at the same time. These related collections provide a convenient way to compare devices, plan spares, and standardise your sensing hardware.
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SICK Sensors ➜
Explore a wide range of SICK products—from photoelectric and distance sensors to encoders and safety devices—ideal when you want to stay within the same brand family as the SICK WTA24-P5401 infrared distance sensor. -
Sensors ➜
Browse a broad portfolio of industrial sensors, including photoelectric, inductive, capacitive, and distance sensors, to find complementary or alternative devices that can work alongside or replace the SICK WTA24-P5401 infrared distance sensor. -
Sensor Cables ➜
Ensure reliable wiring and clean installations with M8/M12 and other sensor cables that pair perfectly with distance sensors like the SICK WTA24-P5401 infrared distance sensor.
Is the SICK WTA24-P5401 infrared distance sensor right for your application?
If you are still using the SICK WTA24-P5401 infrared distance sensor in existing equipment, you already know its strengths: robust construction, simple wiring, dual PNP outputs plus a 4–20 mA analog signal, and reliable mid-range performance. It is particularly well suited for applications such as:
- Level monitoring in shallow bins or hoppers
- Diameter measurement on coils and rolls
- Height and profile checks on conveyors
- Positioning of carriages, forks, or gantries
- Loop and sag control in web handling
Where the SICK WTA24-P5401 infrared distance sensor is less ideal is in ultra-fast, high-precision positioning at very short ranges, or in extremely long-range distance measurement beyond a few meters. In those cases, modern laser displacement or time-of-flight sensors provide better performance.
If you are designing a new system, you can still use the datasheet and behavior of the SICK WTA24-P5401 infrared distance sensor as a reference model when selecting a newer device. Simply match the measuring range (around 0.6–1.2 m), the need for 4–20 mA output, and the requirement for discrete switching outputs. Then, choose a modern sensor that fits those needs.
Conclusion: Getting the most from the SICK WTA24-P5401 infrared distance sensor
The SICK WTA24-P5401 infrared distance sensor is a great example of how a well-designed distance sensor can bridge the gap between simple on/off detection and full analog measurement. With its 600–1,200 mm measuring range, rugged IP67 metal housing, two PNP switching outputs, and 4–20 mA analog signal, it has served as a reliable workhorse in countless factories around the world.
Even though the SICK WTA24-P5401 infrared distance sensor is now discontinued, understanding how it works and where it excels helps you maintain existing installations, troubleshoot issues, and specify suitable replacement devices. Its triangulation-based measurement, background suppression, and balanced response time make it a solid benchmark for mid-range distance sensing in industrial environments.
If you are currently maintaining equipment that uses the SICK WTA24-P5401 infrared distance sensor, or you are evaluating similar sensors for a new project, it’s worth exploring detailed product information, wiring diagrams, and application notes on the product page. There you can review specifications, check availability, and compare potential replacement options so you can keep your automation systems running smoothly without unnecessary downtime.
