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ExDelSE instruction on CR200X

galexioza Oct 22, 2015 01:13 AM

Can someone please tell me if the ExDelSE() instruction on a CR200X outputs Vs (measured voltage) or Vs/Vx (measured voltage/excitation voltage)? The 237 manual from Campbell Scientific says that ExDelSE() outputs Vs/Vx, but it seems to me that it is outputting Vs (i.e. the voltage being measured by the analogue channel).

I am trying to use a 237 wetness sensor with a modified instruction (below). It's to get a mean hourly percentage wetness measurement for use in plant disease models.

Thanks in advance.


ExDelSE(WetVoltage,1,3,1,mv2500,500,1,0)

Wet_kOhms = (2500/WetVoltage)-101

If Wet_kOhms > 0 AND Wet_kOhms < 150 Then
Wetness = 50 + (150 - Wet_kOhms)/3
ElseIf Wet_kOhms > 150 Then
Wetness = 7500/Wet_kOhms
Else
Wetness = 0
EndIf

JDavis Oct 22, 2015 04:23 PM

From the help in CRBasic for ExDelSE:

With a multiplier (mult) of 1 and an offset of 0, the output is in millivolts.

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