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SYSTEM
The drop counter adds robustness and resolution to the precipitation measurement in the
following ways:
•
The drop counter does not have moving parts and is not subject to mechanical wear and
particulate contamination issues that can cause inaccuracy or complete failure. The
tipping spoon mechanisms do have moving parts with friction surfaces and are subject to
mechanical wear and particulate contamination issues.
•
The drop counter ensures that any water that comes through the funnel is counted in the
total. The resolution of the drop counter is 0.017 mm, which is an order of magnitude better
than conventional tipping spoon gauges. Small amounts of rainfall that are insufficient
to cause the spoon to tip can evaporate over time and therefore, never be counted in the
rainfall total.
The tipping spoon adds robustness to the ATMOS 41W rainfall measurement in the
following ways:
• Extends the measurement range to capture extreme rainfall events of up to 2000 mm/hr (the
drop-counting method becomes unreliable at extremely high rainfall rates [>400 mm/hr]).
• Extends the off-level tolerance for rainfall measurement. If the ATMOS 41W is off-level by
significantly more than 2 degrees, drops can miss the gold pins and will not be counted.
• The tipping spoon is not susceptible to electromagnetic interference (EMI). In some
extreme cases, close proximity lightning or other strong sources of EMI can manifest as
artificial drops to the drop counters.
IMPORTANT
The ATMOS 41W must be within approximately ±2° of dead level to measure rainfall with the best resolution. If not
within this range, drops from the flared hole can miss the gold electrodes entirely.
3.2.2.1 REMOVE RAIN FUNNEL
The rain funnel may occasionally need to be removed in the following instances:
• Starting (or restarting) the Bluetooth connection (
),
• Cleaning (
),
• Replacing the rain funnel for pyranometer recalibration.
The rain funnel locks in place using two pegs on the side of the rain funnel. To remove the
rain funnel do the following:
1. Discharge static electricity from the ATMOS 41W body by touching any conductive
material not isolated from the ground (e.g., metal pole).
NOTE: An electrostatic discharge (ESD) can damage ATMOS 41W electronics.
2. Press the rain funnel down to compress the internal spring.
