wtw Cond 7110 - Calibration: Why and When to Calibrate; Determining the Cell Constant

Cond 7110 Conductivity
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5.2 Calibration
5.2.1 Why calibrate?
Aging slightly changes the cell constant, e. g. due to coatings. As a result, an
inexact measured value is displayed. The original characteristics of the cell can
often be restored by cleaning the cell. Calibration determines the current value
of the cell constant and stores this value in the instrument.
Thus, you should clean and calibrate at regular intervals (we recommend:
every 6 months).
5.2.2 When to calibrate?
• When the cleaning interval has expired
• Routinely within the framework of the company quality assurance
5.2.3 Determining the cell constant (calibration in control standard)
This method can be used for measuring cells with cell constants in the following
ranges:
• 0.450 ... 0.500 cm
-1
• 0.800 ... 0.880 cm
-1
A 0.01 mol/L KCl solution is used as control standard.
1. Open the calibration menu with <CAL>.
2. If necessary, select the calibration type (Cal Cell) with <CAL>.
Cal Cell is displayed.
3. Confirm the selection of (Cal Cell) with <ENTER> or <CAL__>.
The cell constant of the last calibration is displayed.
L
CL
E
L
A
C