Instruction Manual Section 10: Calibration
LIQ-MAN-56 April 2017
Calibration 75
Section 10.0 Calibration
10.1 Calibration – Introduction
Calibration is the process of adjusting or standardizing the analyzer to a lab test or a
calibrated laboratory instrument, or standardizing to some known reference (such as a
commercial buffer). The auto-recognition feature of the analyzer will enable the appropriate
calibration screens to allow calibration for any single sensor configuration or dual sensor
configuration of the analyzer. Completion of Quick Start upon first power up enables live
measurements but does not ensure accurate readings in the lab or in process. Calibration
should be performed with each attached sensor to ensure accurate, repeatable readings.
This section covers the following programming and configuration functions:
1. Auto buffer cal for pH (pH Cal - Sec.7.2)
2. Manual buffer cal for pH (pH Cal - Sec.7.2)
3. Set calibration stabilization criteria for pH (pH Cal - Sec.7.2)
4. Standardization calibration (1-point) for pH, ORP and Redox (pH Cal - Sec.7.2 and 7.3)
5. Entering the cell constant of a conductivity sensor (Conductivity Cal - Sec. 7.4 and 7.5)
6. Calibrating the sensor in a conductivity standard Conductivity Cal - Sec. 7.4 and 7.5)
7. Calibrating the analyzer to a laboratory instrument (Contacting Conductivity Cal - Sec.7.4)
8. Zeroing an chlorine, oxygen or ozone sensor (Amperometric Cal - Sec’s 7.6, 7.7, 7.8)
9. Calibrating an oxygen sensor in air (Oxygen Cal - Sec’s 7.6)
10. Calibrating the sensor to a sample of known concentration (Amperometric Cal - Sec’s
7.6, 7.7, 7.8)
11. Enter a manual reference temperature for temperature compensation of the
process measurement
10.2 pH Calibration
New sensors must be calibrated before use. Regular recalibration is also necessary. Use auto
calibration instead of manual calibration. Auto calibration avoids common pitfalls and
reduces errors. The analyzer recognizes the buffers and uses temperature-corrected pH
values in the calibration. Once the 56 successfully completes the calibration, it calculates and
displays the calibration slope and offset. The slope is reported as the slope at 25 °C.
To calibrate the pH loop with a connected pH sensor, access the Calibration screen by
pressing ENTER/MENU from the main screen, select S1 or S2 Measurement and press
ENTER/MENU. Press INFO at any time to learn more about this procedure. A yellow screen
will appear with detailed instructions and information.
The following calibration routines are covered:
1. Auto Calibration - pH 2 point buffer
calibration with auto buffer
recognition
2. Manual Calibration - pH 2 point buffer
calibration with manual buffer value
entry
3. Standardization - pH 1 point buffer
calibration with manual buffer value
entry
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