Campbell CR800 Series - Fieldcal() Slope (Opt 3) Example

Section 7. Installation
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'measurements), the routine is complete. Note the new values in variables FlowMultiplier and
'FlowOffest. Now enter a new value in the simulated sensor signal as follows and note
'how the new multiplier and offset scale the measurement:
' SimulatedFlowSignal = 1000
'NOTE: This program places a .cal file on the CPU: drive of the CR800. The .cal file must
'be erased to reset the demonstration.
'DECLARE SIMULATED SIGNAL VARIABLE AND SET INITIAL MAGNITUDE
Public SimulatedFlowSignal = 300 'Excitation mV, second setting is 550
'DECLARE CALIBRATION STANDARD VARIABLE AND SET MAGNITUDE
Public KnownFlow = 30 'Known flow, second setting is 10
'DECLARE MEASUREMENT RESULT VARIABLE.
Public Flow
'DECLARE MULTIPLIER AND OFFSET RESULT VARIABLES AND SET INITIAL MAGNITUDES
Public FlowMultiplier = 1
Public FlowOffset = 0
'DECLARE VARIABLE FOR FieldCal() CONTROL
Public CalMode
'DECLARE DATA TABLE FOR RETRIEVABLE CALIBRATION RESULTS
DataTable(CalHist,NewFieldCal,200)
SampleFieldCal
EndTable
BeginProg
'LOAD CALIBRATION CONSTANTS FROM FILE CPU:CALHIST.CAL
'Effective after the zero calibration procedure (when variable CalMode = 6)
LoadFieldCal(true)
Scan(100,mSec,0,0)
'SIMULATE SIGNAL THEN MAKE THE MEASUREMENT
'Multiplier calibration is applied when variable CalMode = 6
ExciteV(Vx1,SimulatedFlowSignal,0)
VoltSE(Flow,1,mV2500,1,1,0,250,FlowMultiplier,FlowOffset)
'PERFORM A MULTIPLIER CALIBRATION.
'Start by setting variable CalMode = 1. Finished when variable CalMode = 6.
'FieldCal(Function, MeasureVar, Reps, MultVar, OffsetVar, Mode, KnownVar, Index, Avg)
FieldCal(2,Flow,1,FlowMultiplier,FlowOffset,CalMode,KnownFlow,1,30)
'If there was a calibration, store it into a data table
CallTable(CalHist)
NextScan
EndProg
7.7.11.5.4 FieldCal() Slope (Opt 3) Example
Most CRBasic measurement instructions have a multiplier and offset parameter.
FieldCal() Option 3 adjusts the multiplier argument such that the output of the
sensor being calibrated is set to a value consistent with the linear relationship that
intersects two known points sequentially entered in the FieldCal() KnownVar