Campbell Scientific CR3000 Micrologger - Manual (Page 157)

Section 7. Installation
157
each with two supporting instructions:
• LoadFieldCal() — an optional instruction that evaluates the validity of, and
loads values from a CAL file.
• SampleFieldCal — an optional data-storage output instruction that writes the
latest calibration values to a data table (not to the CAL file).
and a reserved Boolean variable:
• NewFieldCal — a reserved Boolean variable under CR3000 control used to
optionally trigger a data storage output table one time after a calibration has
succeeded.
See CRBasic Editor Help for operational details on CRBasic instructions.
7.8.1.3 Calibration Wizard Overview
The LoggerNet and RTDAQ field calibration wizard steps through the calibration
process by performing the mode-variable changes and measurements
automatically. The user sets the sensor to known values and inputs those values
into the wizard.
When a program with FieldCal() instructions is running, select LoggerNet or
RTDAQ | Datalogger | Calibration Wizard to start the wizard. A list of
measurements utilized in any FieldCal() instruction in the program is shown.
For more information on using the calibration wizard, consult LoggerNet or
RTDAQ Help.
7.8.1.4 Manual Calibration Overview
Manual field calibration through the on-board keyboard and display is presented
here to introduce the use and function of the FieldCal() and FieldCalStrain()
instructions. This section is not a comprehensive treatment of field calibration
topics. The most comprehensive resource to date covering use of FieldCal() and
FieldCalStrain() is RTDAQ software documentation. Be aware that,
• the CR3000 does not check for out-of-bounds values in mode variables.
• valid mode variable entries are "1" or "4".
7.8.1.4.1 Single-Point Calibrations (zero, offset, or zero basis)
Use this single-point calibration procedure to adjust an offset (y-intercept). See
Zero (Option 0)
(p. 160)
and Offset (Option 1)
(p. 160)
for demonstration programs:
1. Use a separate FieldCal() instruction and separate field cal variables for each
sensor to be calibrated. In the CRBasic program , put the FieldCal()
instruction immediately below the associated measurement instruction.
2. Set mode variable = 0 or 6 before starting.
3. Place the sensor into zeroing or offset condition.
4. Set KnownVar variable to the offset or zero value.
5. Set mode variable = 1 to start calibration.