Campbell Scientific CR9000X Measurement and Control System User Manual

Page 362

Section 9. Program Control Instructions

ZERO CALIBRATION STEPS (Function = 0)

1. If the Reps and Index parameters are constants, go to Step 2.
If

the

Reps and Index parameters are variables then either:

Individual Sensor Cal: Set the Reps parameter to 1 and select the

individual sensor to be zeroed by setting the Index parameter or;

Complete Array Cal: Set the Index parameter to 1 and the Reps

parameter to the number of elements in the MeasVar variable array.

This will zero all of the elements of the array together.

2. Change the Mode value to 1 while the sensor(s) are at their Zero state. After

the calibration is complete, the logger will change the Mode value to 6.

OFFSET CALIBRATION STEPS (Function = 1)

1. If the Reps and Index parameters are constants, go to Step 2.
If

the

Reps and Index parameters are variables then either:

Individual Sensor Cal: Set the Reps parameter to 1 and select the

individual sensor to be calibrated by setting the Index parameter or;

Complete Array Cal: Set the Index parameter to 1 and the Reps

parameter to the number of elements in the MeasVar variable array.

This will calibrate all of the elements of the array together.

2. Set the KnownVar(s) to the desired offset value(s). Change the Mode value

to 1 while the sensor(s) are at the Offset state(s). The OffsetVar(s) value(s)

will be set such that the output variable(s) for the sensor(s) will be at the

KnownVar(s) offset value(s) when the sensor(s) experiences the offset state.

After the calibration is complete, the logger will change the Mode value to 6.

TWO POINT CALIBRATION STEPS (Function = 2 OR 3)

1. If the Reps and Index parameters are constants, go to Step 2.
If

the

Reps and Index parameters are variables then either:

Individual Sensor Cal: Set the Reps parameter to 1 and select the

individual sensor to be calibrated by setting the Index parameter or;

Set

the

Index parameter to 1 and the Reps parameter to the number of

elements in the MeasVar variable array. All of the elements of the

KnownVar array will have to be set in steps 2 and 4 below. This will

calibrate all of the elements of the array together.

2. Apply the first condition to sensor(s). Set the KnownVar parameter(s) to the

value(s), in the desired engineering units, for this condition.

3. Change the Mode value to 1. The logger will record this first point and its

corresponding voltage output(s), and then change the Mode value to 3.

4. Apply the second condition to sensor(s). Change the KnownVar

parameter(s) to the value(s), in the correct engineering units, for this

condition.

5. Change the Mode value to 4. The logger will calculate the multiplier(s) and

offset(s) (offsets only for Function 2), populate the MultVar(s) and

OffsetVar(s) with them, and change the Mode value to 6.

For all Functions, when a calibration is complete, the logger will change the

Mode value to 6, the *.CAL file will be updated, and the NewFieldCal

function state will be changed to True. The NewFieldCal function can be used

to trigger a user created Data Table to store the calibration factors. The values

from the *.CAL file can be loaded back into the calibration variables using the

LoadFieldCal instruction.

Campbell Scientific recommends that the user record the
calibration constants to a data table and upload them to his PC
for a record.

NOTE

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