WindSonic Doc No 1405 PS 0019 Issue 28 November 2019
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9.7.9 Low wind speeds (below 0.05 m/s).
Whilst the wind speed is below 0.05 metres/sec, the wind direction will not be calculated.
In both CSV mode and in Fixed Field mode, Channel 2 wind direction output will freeze at
the last known valid direction value until a new valid value can be calculated.
The above applies with the K command set for K50. If K for instance is set for 100 then the
above applies at 0.1m/s.
Wind Speed Condition
Channel 1 Speed Output
Channel 2 Direction Output
Greater Than 0.05m/s
0-5v, 0/4 – 20mA variable
0-5v, 0/4 – 20mA variable
Less Than 0.05m/s
0-5v, 0/4 – 20mA variable
Hold last known good
reading above 0.05m/s
speed until wind speed
increases above 0.05m/s
9.7.10 Error condition reporting
In both CSV and Fixed Field Modes, if a valid wind measurement cannot be calculated due
to a fault condition (for example all paths blocked), the Analogue outputs on Channels 1 and
2 can report a digital error status condition depending on the Y command setting.
NOTE:
The Y command is not applicable to WindSonic 75 Analogue output units.
WindSonic 75 units will report Error conditions as though set for Y1 below.
Y1 setting (Default).
Under data error conditions will switch back and forth between 0 and 5V (or 0/4 to 20mA) at
the selected output rate.
The following table summarises the above reporting conditions with Analogue Outputs set
for Polar Continuous Output and 0-5v (T1), 0-20mA (T5) and 4-20mA (T3).
Wind Speed Condition
Channel 1 Speed
Channel 2 Direction
Digital Error Code
Output e.g. 01, 02, 04
etc.
Cycle 0 – 5 – 0 v
at output rate
Cycle 0 – 5 – 0 v
at output rate
Cycle 0 – 20 – 0 mA
at output rate
Cycle 0 – 20 – 0 mA
at output rate
Cycle 4 – 20 – 4 mA at
output rate
Cycle 4 – 20 – 4 mA at
output rate
