weighing rain gauge rain [e]

The precipitation sensor rain[e] measures precipitation amount and intensity. The rain[e] combines the advantages of the latest weighing technology and a self-emptying monolithic manufactured precision tipping bucket, allowing a high resolution and high precision at a very small total volume. Therefore the rain[e] has a higher resolution and precision than common tipping bucket sensors and at the same time is much smaller than common weighing sensors, since there is no need for a collecting container. The main sensor is a highly precise weighing cell with overload protection. Its temperature coefficient will be determined using a temperature sensor in the interior space if necessary. The pulses from the reed contact generated by tipping the tipping bucket are used for error correction during periods of high precipitation intensity. Furthermore, the self-emptying of the tipping bucket allows weighing without interruption. The rain[e] calculates the following values:

 

 ► Amount of precipitation (Pulse or Analogue Output) The rain[e] gives the amount of precipitation in real time via the Pulse or Analogue Output with a maximum resolution of 0.01 mm.

 

► Intensity of the last minute (SDI-12 or RS485 interface) The rain[e] measures 6 times per minute and sums these values up in a moving sum - that is, every time a new value is measured, it will be summed to the previous 5 values and thus generate the new intensity of the last minute. Fig. 1 Fig. 2 Measuring edge Protective covering Fastening screw Mounting pedestal Pole/tube Mounting screws Connector heating power 4 Dimensional Drawing and Product Drawing Connector sensor rain[e] Precipitation Sensor Operating Instructions 5 Operating Instructions Precipitation Sensor rain[e]

 

► Intensity since last retrieval (SDI-12 or RS485 interface) The difference in the amount since the last retrieval is divided by the time since the last retrieval. If the time is smaller than 30 s, the rain[e] will use the intensity of the last minute value

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► Amount since last retrieval (SDI-12 or RS485 interface) The difference in the amount between the new and the last retrieval.

 

► Minimum intensity of the last x minutes (SDI-12 or RS485 interface) Every minute the value of the intensity of the last minute will be compared to the current minimum value. If the new value is smaller, it replaces the former minimum value.

 

► Maximum intensity of the last x minutes (SDI-12 or RS485 interface) Every minute the value of the intensity of the last minute will be compared to the current maximum value. If the new value is bigger, it replaces the former maximum value.

 

► Average intensity of the last x minutes (SDI-12 or RS485 interface) Counts the amount of precipitation in steps of 0.01 mm for x minutes and divides the result by x minutes.

 

► Variance (SDI-12 or RS485 interface) Variance of measured values over 4 s The two pulse outputs can be configured to return the amount of precipitation with resolutions between 0.01 and 1 mm and closing times between 10 and 500 ms . Alternatively they can be configured to return the status Heating ON/OFF or Rain YES/NO. The analogue output can be used in the two modes 0/4...20 mA or 0...2.5/5 V DC to return the amount of precipitation. For further details on the functioning of the analogue output and the reset function. In addition to SDI-12, the RS485 interface can be used in Talker or WL ASCII mode

 

 

Heating

For applications in regions with seasonal or permanent cold climate the rain[e] is available as a heated version. To melt solid precipitation in the funnel and prevent the outlets from complete icing the internal heating of the heated rain[e] is separated into two parts. An 80 W heating pad along the funnel surface and a 60 W heating plate below the protective wired grid and the tipping bucket. The targeted temperature of the inner funnel surface is 2 °C. The heated rain[e] is operational at -40...70 °C. The operational readiness is checked continuously and can be requested via SDI-12, RS485 or pulse output .The heating can be switched off via the configuration software rain[e] Commander. In the factory settings the heating is switched on. The heating uses a separate power cable.

 

 

 Installation

Site Selection

 

To minimise in-splashing it is recommended to avoid sites with hard ground like concrete and place the precipitation sensor on grass or other soft ground instead. In general the gauge should not been placed on slopes or roofs. We recommend installation of the precipitation sensor at a distance of at least 2 m from any obstacle or the obstacle height (above the gauge's orifice), as defined by the DWD or twice the obstacle height as defined by the WMO and preferably at a distance of four times the obstacle height. Overgrowing plants around the site have to be clipped regularly to the height of the gauge to prevent them from disturbing the measurement and at the same time reduce wind influence.