Why is a precipitation sensor used?

Reliable detection of precipitation is crucial in many areas of application – from traffic control technology to sewage treatment plants and building management. Incorrect or delayed precipitation detection can lead to accidents, inefficient processes or damage to property.

The IRSS88 and IRSS88T precipitation sensors from RLS Wacon are opto-electronic precipitation detectors that have been used successfully for years in traffic control systems, sewage treatment plants and building management worldwide. They reliably detect all types of atmospheric precipitation – rain, drizzle, hail and snow – and impress with their instantaneous response and extreme robustness. The IRSS88T also offers integrated temperature measurement with 0.1 °C resolution, potential-free relay outputs and an RS232 interface.

How do the IRSS88 / IRSS88T precipitation sensors work?

Based on a light barrier principle with high-performance infrared technology, the sensors generate an active detection area of approx. 120 × 25 mm. This area is sufficient to reliably detect even low precipitation densities with the smallest particle sizes.

The opto-electronic principle reacts instantaneously to particles that pass through the sensor zone. The highly sensitive microelectronics are insensitive to any kind of interfering light – even intense sunlight. The all-metal housing ensures effective shielding against HF radiation.

Signal outputs IRSS88

The IRSS88 has three signal outputs:

All outputs are designed as PNP open collectors and require pull-down resistors (recommended: 1-10 kΩ). All outputs are short-circuit proof.

Additional functions of the IRSS88T

The IRSS88T contains a separate temperature sensor in an aluminum attachment on the core housing. This makes it possible to measure the ambient temperature to an accuracy of 0.1 °C and to control a potential-free switching output via a switching hysteresis function. The hysteresis can be set as required between 0 °C and 9 °C using two rotary selector switches.

Adjustable response threshold

The response threshold of the weighted output SOUT can be set to 1 to 15 pulses per time interval (approx. 95 s) using a rotary switch on the receiver circuit board. This allows the signaling of insignificant amounts of precipitation to be suppressed. The factory setting is 4 pulses.

Advantages of the IRSS88 / IRSS88T precipitation sensors

• Reliable detection of all types of precipitation

  Rain, drizzle, hail and snow are reliably detected even with the smallest particle size

• Delay-free reaction

  The opto-electronic principle reacts immediately to particles in the sensor zone

• Extremely robust stainless steel housing with protection class IP68

  Waterproof all-metal housing made of stainless steel (V2A) – suitable for extreme environmental conditions

• Insensitive to interfering light

  Reliable operation even in intense sunlight thanks to highly selective IR technology

• Alarm output for soiling

  The SACT output informs the operator if the sensor windows are heavily soiled or iced up

• Connection cable up to 1000 m possible

  Wide operating voltage range (9-18 V DC) and low current consumption enable long cable runs

• Adjustable response threshold

  Rotary switch for 1-15 pulses per time interval – insignificant amounts of precipitation can be suppressed

• IRSS88T: Integrated temperature measurement with 0.1 °C resolution

  Separate temperature sensor with adjustable switching hysteresis, analog temperature output and RS232 data protocol

Der Beitrag Precipitation sensor IRSS88 erschien zuerst auf RLS Wacon analytics.