Campbell Scientific CR3000 Micrologger - Manual (Page 160)

Section 7. Installation
160
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 to SE6(3L) to simulate a sensor
Public mV 'Excitation mV Output
Public KnownRH 'Known Relative Humidity
Public CalMode 'Calibration Trigger
Public Multiplier 'Multiplier (Starts at .05 mg / liter / mV,
'does not change)
Public Offset 'Offset (Starts at zero, not changed)
Public RH '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,mV5000,6,1,0,250,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.