What the SICK DS35-B15821 Switching Sensor Delivers

The SICK DS35-B15821 is a Dx35 switching sensor that uses HDDM optical time-of-flight measurement to detect targets across a 50 mm to 12,000 mm range at 90% remission. For maintenance engineers, this means one compact unit covers long-distance presence checks without a reflector. The sensor is built for demanding environments and reports status over IO-Link V1.1 on Q1.

On a plant floor, sensor failures usually trace back to heat, moisture or unstable power. This unit addresses these conditions with a wide operating temperature window, reverse-polarity protection and an IP65 housing. Consequently, it suits mission-critical positions where a missed detection stops a line.

Key Features and Technical Specifications

• Measurement principle: HDDM optical time-of-flight for distance-based switching.
• Measuring range: 50 mm ... 12,000 mm at 90% remission.
• Reduced-remission range: 50 mm ... 5,300 mm at 18% and 50 mm ... 3,100 mm at 6%.
• Light source: Infrared laser diode at 827 nm, Class 1 eye-safe per IEC 60825-1:2014.
• Response time: 2.5 ms at Super Fast, up to 96.5 ms at Super Slow.
• Repeatability: 0.5 mm ... 5 mm, depending on speed setting and remission.
• Switching frequency: Up to 333 Hz, speed setting dependent.
• Outputs: Two push-pull digital outputs (PNP/NPN, Q1 and Q2) plus a multifunctional input.
• Supply voltage: DC 12 V ... 30 V, reverse-polarity protected.
• Power consumption: ≤ 1.7 W at +20 °C, without load, speed setting Slow.
• Electrical connection: Male connector M12, 5-pin.
• Enclosure rating: IP65 per EN 60529.
• Housing: Plastic (ABS/PC) with acrylic glass (PMMA) optical window.
• Dimensions: 32 mm x 58.6 mm x 42.7 mm.
• Weight: Approx. 65 g.

The 2.5 ms response time stands out for high-speed sorting. At that setting, the sensor keeps pace with fast-moving targets while the IO-Link link reports status to the controller.

Operating Temperature, Input Voltage and Power Supply

Ambient temperature for operation is -30 °C ... +55 °C with Uv ≤ 24 V, while storage covers -40 °C ... +75 °C. These limits let the sensor serve outdoor washdown areas and cold storage zones alike. In addition, the DC 12 V ... 30 V supply range tolerates the voltage sag common on long machine feeds. Note that IO-Link requires Vs > 18 V when active. Power consumption stays at or below 1.7 W at +20 °C without load on the Slow setting, so heat build-up inside cabinets is minimal. For maintenance teams, this low draw reduces thermal stress on nearby wiring.

Installation and Setup for Maintenance Teams

Mount This unit using its 32 mm x 58.6 mm x 42.7 mm housing footprint and connect the M12 5-pin male connector. The integrated optical alignment aid speeds up aiming during commissioning. Because the switching hysteresis is adjustable from 0 mm ... 11,950 mm, engineers can tune the output to ignore background objects. Set the response time to match the process: Super Fast for indexing, Super Slow for averaging over noisy targets. After wiring, verify the supply voltage stays within DC 12 V ... 30 V under load. When IO-Link is used, confirm Vs > 18 V at the device.

Reliability and Maintenance in Oil and Gas Environments

In oil and gas service, sensors face vibration, temperature swings and dust. The IP65 housing and PMMA optical window resist dust ingress, yet the window still needs periodic wiping. Inspect the window and connector quarterly, and more often in dirty areas. Check the M12 connector for moisture and tighten it to prevent intermittent faults. Because the laser is Class 1 eye-safe, routine inspection needs no special eyewear. However, follow the manufacturer's safety manual for all service work. The wide operating temperature range of -30 °C ... +55 °C means the unit tolerates hot process areas and cold climates. Therefore, it delivers reliability you can depend on across seasonal swings.

Integration with Control Systems

The two push-pull outputs (PNP/NPN) connect directly to most PLC digital inputs. IO-Link V1.1 on Q1 carries parameter data and status to an IO-Link master. Integration Note: wiring into IO-Link networks may require an external gateway or connection module; confirm cables and gateways with the supplier. The multifunctional input adds flexibility for triggering or reset functions.

Frequently Asked Questions

What is the measuring range of the SICK unit?

The SICK unit measures 50 mm ... 12,000 mm at 90% remission, 50 mm ... 5,300 mm at 18% and 50 mm ... 3,100 mm at 6%.

What supply voltage does This unit require?

It operates on DC 12 V ... 30 V with reverse-polarity protection. When IO-Link is active, the supply must exceed 18 V.

How does This unit handle high-speed detection?

At the Super Fast setting, response time is 2.5 ms and switching frequency reaches up to 333 Hz, depending on the speed setting.

Is the laser in This unit eye-safe?

Yes. The infrared laser diode is Class 1 per IEC 60825-1:2014 and EN 60825-1:2014, so it is eye-safe under normal use.

What maintenance does This unit need?

Inspect the PMMA optical window and M12 connector periodically. Clean the window when dusty and verify the supply voltage stays within DC 12 V ... 30 V.

Contact PetroPartsOnline for parts suited to your application's requirements.

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