Field Calibration Of Linear Sensors (Fieldcal) - Campbell CR1000 Operator's Manual

Section 11. Programming Resource
Library
11.1 Field Calibration of Linear Sensors
(FieldCal)
NOTE
11.1.1 CAL Files
NOTE
Calibration increases accuracy of a measurement device by adjusting its output,
or the measurement of its output, to match independently verified quantities.
Adjusting a sensor output directly is preferred, but not always possible or
practical. By adding FieldCal () or FieldCalStrain () instructions to the
CR1000 program, a user can easily adjust the measured output of linear sensors
by modifying multipliers and offsets.
Once programmed in the CR1000, calibration functions are accessed through a
software wizard (LoggerNet | Connect | Tools | Calibration Wizard) or through
a numeric monitor procedure using keypad or software. The numeric monitor
procedure, though somewhat arcane, is utilized in the examples below to
illustrate calibration functions and procedures.
LoggerNet calibration
FieldCalStrain ().
Calibration data are stored automatically in CAL files in CR1000 memory,
which become the source for calibration factors when requested with the
LoadFieldCal instruction.
A CAL file is created automatically on the same drive and given the same
name (with .cal extension) as the program that creates and uses it, e.g.,
CPU:MyProg.CR1 generates CPU:MyProg.cal.
CAL files are created if a program using FieldCal () or FieldCalStrain () does
not find an existing compatible CAL file. Files are updated with each
successful calibration and contain multiplier and offset factors and information
for the LoggerNet Calibration Wizard. If the user creates a data storage output
table in the CR1000 program, a calibration history will be maintained.
CAL files created by FieldCal () and FieldCalStrain () differ
from files created by the CalFile () instruction (Section 10.14
File Management).
wizard does not yet support
11-1