WSX53B WEATHER SENSOR
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The new WSX53 is a robust electronic precipitation detector designed for controlling many systems where there is need to respond to external weather conditions. Such systems include ■ Building Automation ■ Plant Automation ■ Commercial and Residential Homes ■ Weather Centres ■ Sprinkler Control ■ Agricultural use, etc. ■ De-icing and drying systems It may be required to activate things such as ■ Blowers ■ Pumps ■ Heaters ■ Boilers ■ Door or window closers ■ Shutters, or other items in response to external weather conditions. With its wide operating temperature range and leak proof IP66 enclosure, it is suitable for use in many inhospitable situations. Principle of Operation The detector consists of two essential parts (see Figure 2). There is a humidity sensor which senses any precipitation without discrimination, that is, rain, snow, hailstone, sleet are all detected the same. The humidity sensor is complemented by an ambient temperature sensor which is used to sense snow point and thus discriminate between rain on the one hand and snow, sleet or hailstone on the other. Precipitation at or below snow point is interpreted as “Snow”. The WSX53 is fully self contained and requires only the application of an external low voltage power supply to be operational. Its outputs are a pair of volt-free contacts which are independent of each other. One set of contacts (S1) is closed if the precipitation sensor detects any precipitation, i.e. when there is water or moisture on it. Otherwise it remains open. To make sure that the sensor still works in case of dry precipitation (hailstone and dry ice), it has a built in heater which maintains the sensor’s temperature always above freezing point. Power Supply This means the sensor is always kept clear and no frozen water or ice is allowed to accumulate on it over any length of time. The other set of contacts (S2) is closed when the controller senses an ambient temperature below snow point. Otherwise, the contacts remain open. Sensor The WSX53 has a proprietary design sensor combining an ingenuous design with a special drive algorithm to ensure long sensor life and effective detection. Output Configuration Each set of contacts will independently sense either Precipitation (S1) or Snow Point Temperature or SPT (S2). To sense only frozen water (snow or hailstone), connect S1 and S2 in series. To sense either Precipitation or SPT, connect S1 and S2 in parallel. Use the contacts independently for separate Precipitation and SPT functions. Time Delay The two contacts, S1 and S2, have a post operative delay timer. The delay timer can be activated by setting two

switches inside the control housing to be either 0 (no delay), 15 minutes, 30 minutes or 45 minutes (see Table 1). Following the end of detection of precipitation or snow point temperature, the contacts would normally open immediately. However, with the delay timer set, the contacts will be kept closed for the duration of the delay timer. The time delay switches determine the delay time for both the precipitation and snow point contacts (S1 and S2) although the two contacts can start and end their delay at different times depending on when they are de-activated by external events. The delay...

5. The snow point relay will similarly de-energise once it warms up above the snow point temperature. Taking care of your WSX53 The WSX53 is designed for outdoor operation and should provide you with many years of trouble free operation if taken care of properly. It should not be thrown about or subjected to excessive shocks. In particular, the humidity sensor should not be subjected to any solvent, abrasive or corrosive substance. If dirt film accumulates on the sensor, this could affect reliable operation of the detector. In this case, rinse the sensor with warm soapy water and gently...