41
SECTION 4,
continued
6. When the value and units are correct, press
ENTER
to
calibrate on the standard. The meter automatically corrects
the calibration measurement to the 25 °C reference
temperature using the NaCl-based, non-linear temperature
coefficient.
7. The meter will return to Conductivity Reading mode when
the calibration is finished.
4.3.2
Calibrating with a Known KCl Standard
The sens
ion
156 meter can be calibrated using either a
1413 µS/cm (0.01 M) or a 12.88 mS/cm (0.1 M) standard
solution. KCl calibration is selected in setup 11 (see Table 7 on
page 38).
1. Make sure the meter is in Conductivity Reading mode.
2. Place the probe in a conductivity standard that is in the
expected range of the samples. Agitate the probe to dislodge
bubbles in the cell. Avoid resting the probe on the bottom or
side of the container.
3. Press.
CAL
. Use the
UP
or
DOWN
arrows to select either the
1413 µS/cm or the 12.88 mS/cm standard.
4. Press
ENTER
to calibrate the standard. The meter
automatically corrects the calibration using the KCl-based
non-linear temperature coefficient.
4.3.3
Calibrating by Adjusting the Cell Constant
The cell constant should be consistent over most of the
measurement range. However, samples having a conductivity
higher than 50 mS/cm may have a slightly different cell constant
than samples with a conductivity less than 50 mS/cm. Follow the
steps below to measure samples with conductivity above and
below 50 mS/cm without recalibrating.
1. Follow Section 4.3.1 or 4.3.2 to calibrate the meter. Be sure
the meter is in the Conductivity mode before calibrating it.
2. After the calibration is complete, press
REVIEW
. The cell
constant for the probe will be displayed. Record this value.
