WindMaster and WindMaster Pro
1561-PS-0001.
Issue 11 February 2017
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8
Effects of temperature, barometric pressure, rainfall and humidity
The calculated u, v and w components are independent of temperature, pressure, rainfall & humidity within the
operating parameters of the WindMaster.
The calculated sonic temperature/speed of sound should be corrected by the user for humidity to provide an indication
of ambient temperature. The calculated Sonic Temperature/Speed of Sound is corrected internally for crosswind.
Measurement sequence
All Modes except Syncpoll 1.
The table shows the firing sequence of the transducers.
Measurement Sequence
The sample rate is automatically selected to either 20Hz or 32Hz, depending on the output rate configured (see section
10.2).
Measurement
Period
Max 50mS (at 20Hz) or 31.25mS (at 32Hz)
Next cycle
Ultrasonic
Measurement
Axis
1
(2mS typical)
2
(2mS typical)
3
(2mS typical
Maths
Routine
(6mS
Typical)
Spare
Time
1
2
Transducer
Firing
L > U
U > L
L > U
U > L
L > U
U > L
L > U
U > L
L > U etc
Analogue Input
Measurement
1, 2, 3 and 4 or PRT
Serial
Communication
Data from previous
measurement.
L > U
Indicates lower to upper transducer firing.
U > L
Indicates upper to lower transducer firing.
Analogue inputs and PRT are sampled synchronously at rates described in Para 8.3.
Syncpoll 1
In this mode when a Poll command is received it will trigger a single 50mS or 31.25mS ultrasonic measurement as
illustrated in the table above and at the same time will trigger a Wind measurement output resultant from the previous
polled measurement.
Notes:-
The minimum poll rate supported in this mode is 20Hz.
Analogue inputs are not supported in Syncpoll mode 1.
Signal processing
Instantaneous Sampling
The WindMaster can be configured to output the sampled data direct at the selected output rate without any averaging -
"Instantaneous Sampling". Alternatively data can be sampled at 20Hz or 32Hz and averaged (see section 10.2 Fx y and
Px). This applies for wind data and speed of sound. All samples are transmitted with a status code.
Retries Enabled
If this mode is selected, if a problem sample is detected, the unit will attempt another ultrasonic firing within the set
time parameters.
Calibration Enabled /Disabled
The on-board calibration (providing compensation for spar and transducer shadowing), can be disabled, returning the
unit to raw, uncorrected operation
Selection of the above parameters is via using Gill Wind software package or using a Terminal Program to set the FX or
Px command.