CR1000 Manual - Campbell Scientific

Section 7. Installation
5. To simulate conditions for a 30-day, service-calibration, again with desiccated
chamber conditions, set variable KnownRH to 0.0. Change the value in
variable CalMode to 1 to start calibration. When CalMode increments to 6,
simulated 30-day, service zero calibration is complete. Calibrated Offset will
equal -52.5%.
CRBasic Example 26.
FieldCal() Zeroing Demonstration Program
'Jumper VX1/EX1 to SE6(3L) to simulate a sensor
Public mV
Public KnownRH
Public CalMode
Public Multiplier
Public Offset
Public RH
'Excitation mV Output
'Known Relative Humidity
'Calibration Trigger
'Multiplier (Starts at .05 mg / liter / mV,
'does not change)
'Offset (Starts at zero, not changed)
'Measured Relative Humidity
'Data Storage Output of Calibration Data -- stored whenever a calibration occurs
DataTable(CalHist,NewFieldCal,200)
SampleFieldCal
EndTable
BeginProg
Multiplier = .05
Offset = 0
LoadFieldCal(true)
'Load the CAL File, if possible
Scan(100,mSec,0,0)
'Simulate measurement by exciting channel VX1/EX1
ExciteV(Vx1,mV,0)
'Make the calibrated measurement
VoltSE(RH,1,mV2500,6,1,0,250,Multiplier,Offset)
'Perform a calibration if CalMode = 1
FieldCal(0,RH,1,Multiplier,Offset,CalMode,KnownRH,1,30)
'If there was a calibration, store it into a data table
CallTable(CalHist)
NextScan
EndProg
7.8.1.5.2 Offset (Option 1)
Case: A sensor measures the salinity of water. Multiplier is known to be stable,
but sensor offset drifts and requires regular offset correction using a standard
solution. The following procedure offsets the measurement to obtain the
calibration report shown.
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