Campbell Scientific CR9000X Measurement and Control System - Manual (Page 366)

Section 9. Program Control Instructions
FieldCalStrain (Function, MeasVar, Reps, GF_Adj, Zero_mVperVolt, Mode,
KnownRs, Index, NumAvg, GF_Raw, uStrain)
Used for performing a zero or shunt calibration function for a strain
measurement. Sets up calibrations on the outputs from a StrainCalc
instruction. The actual calibration operation is simplified using the
Calibration Wizard included in CSI’s software packages. A program using
this instruction will normally require the instructions: LoadFieldCal,
NewFieldCal, and SampleFieldCal.
Syntax for Zeroing
StrainCalc (uSDest(), Reps, mVpV(), Zero_mVpV(), BrConfig, GF_adj(), v)
FieldCalStrain(10, mVpV(), Reps, 0, Zero_mVpV(), Mode, 0, Index, NumAvg, 0, uSDest() )
Syntax for Shunt Calibration
StrainCalc (uSDest(), Reps, mVpV(), Zero_mVV(), BrConfig, GF_adj(), v)
FieldCalStrain(13, uSDest(), Reps, GF_Adj(), 0, Mode, KnownR, Index, NumAvg, GF_Raw(), 0)
Remarks
This instruction is a specialized form of the FieldCal instruction. It is used to
perform zeroing and shunt calibrations on quarter bridge strain, half
bridge bending strain, and full bridge bending strain measurements that use
the StrainCalc function.
When a FieldCalStrain or FieldCal instruction is in a program, a Calibration
file will be created. The location (CPU or Card) of this file will be the same
as the running program that created it. The name of the calibration file will be
the same as the running program that created it with a *.CAL for an extension.
It is recommended that the Reps and Index parameters be non-constant
variables that are initialized to the desired values after the BeginProgram
instruction. This rule can be ignored if setting up calibrations on single
element variables, and the Mode variable parameter for each FieldCalStrain
instruction in the program is represented by a unique variable.
It should be noted that Shunt Calibration does not calibrate the
strain gage, but adjusts the gage manufacturer supplied
calibration gage factor (GF) to compensate for errors introduced
by non-linearity in the Wheat-stone bridge, long leads, and/or
errors in the measurement system. NOTE
When writing a program using a Shunt Calibration, the Reps parameter for
the FieldCalStrain instruction should usually be initialized to 1, and the
GF_Adj, GF_Raw, and KnownR variables should be dimensioned to the size
of the MeasVar variable.
When writing a program for zero calibration, and it is desired to perform
the zero function on all elements of the array during a single scan then:
1. The Reps parameter value should be initialized to the size of the
Source_mVpV variable array,
2. The Reps parameter value should be initialized to the size of the
Source_mVpV variable array,
3. The Index parameter should be initialized to 1.
A Strain Calibration function is started by changing the value of the Mode
parameter to 1. When performing a Zero function, this may be all that is
required (set the Mode to 1 when the sensor is undergoing the desired zero
condition. The steps required for the different calibration functions follow:
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