WM80 measurement data - WM80

WM80 User Guide

Document code
M212995EN
Revision
A
ft:locale
en-US
Product
WM80
Document type
User guide

WM80 measures wind speed and wind direction, as well as provides the air temperature based on the sonic temperature.

Measurement value calculation principle

WM80 measures wind speed and wind direction at 10 Hz rate, meaning that measurement is done every 100 ms. The 10 Hz measurement data values are called sample values. The instant values and statistics are calculated according to the following table. All data values are updated at 100 ms intervals with a user-configurable data output rate.

Measurement values
Measurement Measurement value Description
Sample
  • Wind speed, sample
  • Wind direction, sample
  • Sonic temperature
Fixed 100 ms calculation period.
Instant
  • Wind speed, instant
  • Wind direction, instant
  • User configurable calculation period 0.1–10 s (3 s as default).
  • Instant wind speed and direction values are calculated from sample values as moving average.
Statistics
  • Wind speed, average
  • Wind direction, average
  • Wind speed, gust
  • Wind direction, gust
  • Wind speed, lull
  • Wind direction, lull
  • User configurable calculation period 0.1–3600 s (600 s as default).
  • Average wind speed and direction values are calculated from instant values as moving average.
  • Maximum and minimum instant wind speed values are captured as gust and lull speed values and their directions are captured as gust and lull direction values.

You can configure the calculation period for the instant and statistics values.

Calm wind threshold

You can apply a configurable calm wind threshold during which the last calculated wind direction output is reported until the wind speed increases above the set threshold. The last calculated wind direction output is reported until the wind speed increases enough to reach the threshold.

Invalidation delay

A configurable invalidation delay is used to avoid internal diagnostics from reacting immediately in case of invalid sample values. During the specified invalidation delay period, the device outputs the last valid measurement values.