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U,V,W, SonicT measurement from voltage o/p of RM 81000 in differential mode


dsclimate Nov 20, 2015 11:47 AM

Hello,

I need your kind suggestion for measuring u,v,w wind from RM 81000 anemometer voltage outputs in CR1000.
I have changed the voltage o/p setting to output format one (i.e. u,v,w, sonic temp) using hyper terminal.

However, u,v,w reading are not giving correct values, but, sonic temp is giving correct value.
I am using the following main program in CRBasic for calculation of u,v,w,SonicT
-----------------------
Main Program
'Scan sensors every 100 msec

BeginProg
Scan(100,mSec,1,0)
'Default Datalogger Battery Voltage measurement Batt_Volt:
Battery(Batt_Volt)
'Wiring Panel Temperature measurement RefTemp:
PanelTemp(RefTemp,250)

'RM Young Sonic Anemometer (81000)
'Turn on sensor via control port
PortSet (9 ,1 )
Delay (0,1,mSec)


'Measure Uwind in mV (0-5000mV range)
VoltDiff (Uwind,1,mV5000,1,True ,0,250,1.0,0)
'Convert windspeed mV to m/s
Uwind=(50/5000)*Uwind-25


'Measure Vwind in mV (0-5000mV range)
VoltDiff (Vwind,1,mV5000,2,True ,0,250,1.0,0)
'Convert windspeed mV to m/s
Vwind=(50/5000)*Vwind-25

'Measure Wwind in V (0-5000mV range)
VoltDiff (Wwind,1,mV5000,3,True ,0,250,1.0,0)
'Convert windspeed mV to m/s
Wwind=(50/5000)*Wwind-25


'Measure Sonic temperature in mV
VoltDiff (SonicT,1,mV5000,4,True ,0,250,1.0,0)
'Convert temp mV to celsius
SonicT=((100/5000)*SonicT)+220-273.15


'Turn off sensor via control port
PortSet (9,0)

'Call Data Tables and Store Data
CallTable(Table1)
NextScan
EndProg
-------------------------

Could you please help me further to measure correct u,v,w value from RM young 81000? I am using differential connection.

I would appreciate your kind concern as I stopped here for this without any other help and response. I am really unable to get response from local Campbell Scientific.
Please help.

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