40
SECTION 4,
continued
2. Enter/adjust the cell constant of the conductivity probe. See
Section 4.3.3 for instructions on this calibration method.
4.3.1
Calibrating with a Known NaCl Standard
Hach's Conductivity probe is shipped with a 1000 µS/cm
(at 25 °C) NaCl standard solution. For typical applications with
conductivity of 0–10,000 µS (10 mS/cm), calibrate with this
standard to achieve the accuracy specified for the meter. Outside
this range, calibrate using a standard that lies closer to the
measurement range. In general, using a calibration standard that
is closer to your measurement range results in greater accuracy.
Hach offers several conductivity standards.
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
. Icons that represent the active navigation keys will
appear in the lower part of the display.
The meter will recall the most recent type of calibration. Look at
the units field to see what kind of calibration is active. The units
will be one of the following forms:
4. Scroll to the preferred units using the
UP
or
DOWN
ARROWS
.
5. Use the number keys to change the numeric value, if desired.
The value entered must be the standard’s conductivity value
at a reference temperature of 25 °C.
Note: All Hach standards have the conductivity value corresponding
to the 25 °C reference temperature printed on their labels.
It is not necessary to fill up the numeric entry screen before
moving on. To clear the numeric display, press
CE
.
Units
Calibration Method
µS/cm
Known standard expressed in µS/cm
mS/cm
Known standard expressed in mS/cm
1/cm
Enter/adjust cell constant (see Section 4.3.3)
