EML ARG100 User Manual - page 10
UM-780-400-SBS Manual – V2.00
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5.Operation
Operation of the gauge
Rainfall is measured by the well-proven tipping bucket method. Precipitation is collected by the funnel
and flows through a plastic gauze filter, trapping and removing any leaves, dirt, etc. Figure 4. Water
then drips from the nozzle into one of the two halves of the tipping bucket.
The internal tipping bucket assembly rotates around precision rolling pivot bearings. The balance arm
tips when the first bucket is full, emptying this rain water 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 calibrated fixed quantity of rainfall. At each tip of the bucket the moving arm
forces the magnet past the reed switch causing contact to be made for a few milliseconds. As each
bucket side is used in turn, the outgoing water is drained into the base of the gauge, before flowing
out through plastic gauze filters.
NOTE: The exact calibration of each tip is pre-set by adjustable stops located beneath each tipping
bucket compartment. Do not alter these stops unless as part of a calibration exercise. A levelling
bubble is provided as an aid to levelling of the rain gauge. Connections to the reed switches are made
via the connector terminals.
Figure 4 - Filter and filter cap (left) / Nozzle delivering water into tipping bucket (right)