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The SICK MWS120 Measuring Wheel Encoder is a precision position sensor designed for accurate linear measurement in industrial automation applications. It features an incremental output with high resolution, enabling precise detection of movement through the measuring wheel’s rotation. The encoder is specifically engineered to provide reliable feedback in positioning tasks where accuracy and repeatability are critical. With a measuring increment of 0.0046 mm/pulse, it delivers fine-grained measurement data. Designed for integration into automated systems, the MWS120 ensures consistent performance across varying operating conditions. Its robust construction and IP67 enclosure make it suitable for demanding environments. The product is not classified as a safety component under the Machinery Directive, based on standard operational parameters and nominal load assumptions.
The MWS120 leverages advanced mechanical design and incremental signal technology to deliver high-precision measurement performance. The measuring wheel core is made of aluminum, with a stainless steel spring element ensuring durability and consistent tensioning. This combination minimizes slippage while protecting the measuring surface from damage. The encoder operates with a measuring increment of 0.0046 mm/pulse (based on mounted encoder), providing high resolution for accurate position feedback. Repeatability is less than 0.1 mm, achieved through minimal mechanical backlash in the system design. A reference run is recommended to account for application-specific wheel characteristics such as wear and surface behavior. The measuring wheel’s circumference varies due to manufacturing tolerances, usage, temperature, and surface conditions—making calibration essential for optimal accuracy.
The MWS120 features a communication interface of incremental type using TTL/HTL signals via an 8-pin male M12 radial connector. Supply voltage ranges from 4.5 V to 32 V, with reverse polarity protection and short-circuit protection for output channels (permissible for up to 30 seconds). The maximum permissible working area for the spring is ±10 mm under continuous operation. The unit weight is 1.249 kg (net), and it operates within a temperature range of –30 °C to +80 °C. Storage conditions extend from –40 °C to +100 °C. The measuring wheel’s circumference varies due to manufacturing tolerances, wear, spring tension, and surface behavior—thus, accurate results require application-specific reference runs for positioning tasks.
The MWS120 integrates directly into automation systems via its incremental TTL/HTL output. The 8-pin M12 radial male connector allows secure connection to compatible control systems or PLCs. For optimal performance, the measuring wheel should be mounted at the front of the object being measured, preferably from above; mounting from below is possible but not recommended. Proper mechanical alignment and spring tensioning are essential to prevent slippage without damaging the surface. The correct spring tension ensures reliable measurement under dynamic conditions. A reference run is advised during setup to account for variations in wheel behavior due to environmental or operational factors. All electronic failures are considered hazardous, and integration should follow standard safety practices as outlined in SICK documentation no. 8015532.
The MWS120 is designed for operation across a wide temperature range of –30 °C to +80 °C, making it suitable for both cold and hot industrial environments. It can be stored in temperatures ranging from –40 °C to +100 °C without degradation. The IP67 enclosure rating ensures complete protection against dust ingress and temporary immersion in water up to 1 meter depth. These environmental capabilities support reliable performance in harsh conditions such as outdoor installations or high-moisture environments. However, the measuring wheel surface is subject to wear due to contact pressure, acceleration, speed, temperature, and ambient conditions—regular inspection and replacement are recommended to maintain measurement accuracy over time.
The MWS120 is ideal for applications requiring precise linear position feedback, such as automated material handling, conveyor systems, and robotic positioning. It is particularly suited for tasks where accurate distance measurement or object length detection is required. The encoder’s high resolution and repeatability support reliable performance in continuous operation under standard conditions (8760 hours per year). Applications include edge detection, product counting, and process control where consistent measurement data is essential. Mounting from above is preferred to ensure optimal contact with the surface; however, bottom mounting is feasible. Regular maintenance, including inspection of the measuring wheel for wear, ensures long-term accuracy and system reliability.
| Specification | Value |
|---|---|
| Repeatability | < 0.1 mm 3) |
| Communication interface | Incremental |
| Connection type | Male connector, M12, 8-pin, radial |
| Supply voltage | 4.5 V ... 32 V |
| resolution | in mm/pulse) |
| Interface | detail |
| connector | , M12, 8-pin, radial |
| material | Spring element Stainless steel Measuring wheel core Aluminum |
| Operating temperature | range |
| Storage temperature | range |
| ambient temperature | 40°C, frequency of use 8760 h/a. All electronic failures are considered hazardous. For more information, see document no. 8015532. |
| weight | during spring pretensioning must be taken into account. |
| Measuring increment (resolution in mm/pulse) | 0.0046 1) 2) |
| value | IP67 (IEC 60529) |
| Short-circuit protection of the outputs | ✔ 1) |
| Spring arm mechanism material Spring element Stainless steel Measuring wheel core Aluminum | Spring arm mechanism material | Spring element | Stainless steel | Measuring wheel core | Aluminum |
| Max. permissible working area for the spring (continuous operation) | ± 10 mm |
| Mounting position relative to the measuring object | Preferably from above, from below possible 4) |
| Enclosure rating | IP67 (IEC 60529) |
| Operating temperature range | –30 °C ... +80 °C 1) |
| Storage temperature range | –40 °C ... +100 °C 1) |
| Unit weight | 1.249 Kilograms |
| Net unit weight | 1.249 Kilograms |
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