I have a Thies Clima 4.3151.10.012 (with the protection circuit) hooked up to a CR3000. I'm using the following code to read the wind direction:
BrHalf(WD_raw(1),1,mv5000,3,2,1,5000,False,10000,_60Hz,369,0)
However the deadband seems to occur after about 347 degrees. The wind vane has been calibrated by a 3rd party, which is where the 369 comes from, which accounts for the additional 50 ohms in the protective circuit (2050 / 2000 * 360).
When I measure the wind direction using the following:
VoltSe(WD_raw(1),1,mv5000,3,0,0,_60Hz,369,0)
I'm able to achieve the full range, 0 - 360 degrees.
Is there something about the settling time, integration, reverse excitation in the BrHalf measurement, which relates to how the voltage is excited, that could be causing the issue? We don't have this problem when using Thies instruments without the protective circuit. I've tried some other settings but they only seem to make the issue worse.
I can't use the constant 5V because I need the calibrated output from the Vx channel.
Hello Wood,
I haven't looked into why the ratiometric output of the BrHalf instruction is not working for you, but if VoltSE is working and all you need is a 5V exctation, you can use the ExciteV instruction prior to your VoltSE. The Vx channel will remain high until another instruction using Vx or the end of the scan.
ExciteV (Vx2,5000,2000)
VoltSe(WD_raw(1),1,mv5000,3,0,0,_60Hz,369,0)
That's a good idea, thanks. I'll test it out, and see if there are any issues.