WindSonic GILL - Analogue Outputs and Options

WindSonic Doc No 1405 PS 0019 Issue 25 February 2017
34
9.7 Analogue Outputs and Options
Notes: Analogue outputs are only available from WindSonic Option 3.
Analogue Wind Speed output is in Metres/Second only.
9.7.1 Voltage or Current output
The WindSonic (Option 3) can be configured for either Voltage (0 – 5 V) or Current (0 –
20mA and 4 – 20 mA) outputs.
Important:
1. When using the current outputs, the load resistance between the Analogue outputs (Pins
8 & 9) and Signal Ground (Pin 1) must be <= 300 ohms, including cable resistance.
This is to ensure that the voltage levels on Pins 8 & 9 do not exceed 5V.
2. The current outputs must be returned to Signal Ground (Pin 1).
9.7.2 Analogue Output Modes
Analogue
Outputs
Polar Mode
Modes 2 and 4
NMEA Mode
Modes 5,14,15
&16
UV Mode
Modes 1 and 3
Tunnel Mode
Mode 12
Channel 1
(Pin 8 wrt Pin 1)
Wind Speed
Wind Speed
U
Wind Speed
U Wind Speed
Channel 2
(Pin 9 wrt Pin 1)
Wind Direction
Wind Direction
U Wind Polarity
U Wind Polarity
9.7.3 Polar mode direction wraparound
The Wind Direction in Polar mode can be configured for either Standard (0 - 359) or
Wraparound (0 - 539) options. If the Standard mode is used with a chart recorder, large
swings of the recorder pen will be experienced each time the wind direction passes between
0 and 359. Using the Wraparound mode, when the wind first changes from 0 to 359, there
will be a step change on the output, but after this first time the output will change smoothly
each time the wind passes through 360. (Similarly, the first time the wind veers from 539
to 180; there will be a step change, after which the output will change smoothly).
Wind
Direction
(degrees)
Voltage Output
(0v to 5V)
Current Output
(0mA to 20mA)
Current Output
(4mA to 20mA)
Standard
Wraparound
Standard
Wraparound
Standard
Wraparound
0
0
0
0.00
0.00
4.00
4.00
180
2.5
1.67
10.00
6.67
12.00
9.33
360
5.0
3.
33
20.00
13.33
20.00
14.67
540
N/a
5.0
N/a
20.00
N/a
20.00
WindSonic Doc No 1405 PS 0019 Issue 25 February 2017
35
9.7.4 Wind Speed scaling
Analogue Outputs are always scaled in m/s irrespective of the digital output units of
measurement setting.
The Wind Speed output can be configured such that full-scale output represents 5, 10, 20,
30, 40, 50 or 60 metres/sec.
In all cases zero Wind Speed is represented by 0V, 0mA or 4mA.
9.7.5 Tunnel mode
When configured in Tunnel mode, Channel 1 output represents the wind speed along the U
axis (South – North) scaled as described above.
Channel 2 gives the direction of the wind along the U axis, where a –U vector (= wind from
the N direction) is represented by 0V (or 0mA, 4mA), and a +U vector is represented by 5V
(or 20mA).
9.7.6 Analogue Output Rate
In Continuous and Polled modes the analogue output update rate will be determined by the P
command setting.
9.7.7 Disabled outputs
If the analogue outputs are not required, they can be disabled (Command S9).
9.7.8 Analogue Output Conditions
Analogue signals are output together with Digital Outputs signals.
Analogue signals are output continuously when in Digital Polled Mode.
Note: - The WindSonic provides the power for current output loads. Do not connect the
WindSonic output to instruments where power for the current loop is provided by the
instrument connecting to the WindSonic current output connections.