Gill Instruments Ltd
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MetPak/MetPak RG and MetPak Pro Base Stations
Page | 10
Issue 1
Doc. No. 1723-PS-0023
October 2018
2.1.7.
Precipitation (Digital Input 1).
MetPak RG and MetPak Pro Base Stations:–
Rainfall can be measured by the well-proven tipping bucket method. Rain is collected by a funnel
and is passed to one of the two buckets situated at either end of a short balance arm. The balance
arm tips when the first bucket is full, emptying this bucket and positioning the second bucket under
the funnel. The tipping process repeats indefinitely as long as the rain continues to fall, with each
tip corresponding to a fixed quantity of rainfall; at each tip the moving arm forces a magnet past a
reed switch, causing contact to be made for a few milliseconds.
The Digital input (DIG1), detects when two dedicated terminals are short circuited (less than 1k
ohm). Rain levels are provided by reading the number of switch closures taking place over each
output rate time period (default one reading per second). Then multiplying this number by the Rain
Gauge count figure set using MetSet (e.g. 0.2mm per switch closure) and outputting the result in
the data string.
2.1.8 PRT Temperature (PRT Input)
An external 2 or 4 wire PT100 device can be connected to a MetPak Pro Base Station to provide
an additional remote temperature measurement.
2.1.9 Analogue Sensor 1
An external remote analogue sensor, 0-5v/4-20mA output, can be connected to a MetPak
Pro Base Station AN1 input.
2.1.10 Analogue Sensor 2
An external remote analogue sensor, 0-5v/4-20mA output, can be connected to MetPak
Pro Base Station AN2 input.
2.1.11 Status of MetPak Sensors
Outputs the MetPak Base Station Sensors Status Code (see para 8.3.2).
2.1.12 Supply Voltage
The DC Supply voltage measured at the MetPak Base Station unit is output in the Base Station
Digital Data Output string.
