Hanna Instruments HI 5000 - Manual (Page 22)

22
ments are in the 1.2 to 2.5 EC range. Similarly, utilize
HI 7039L with a value of 5.00 mS/cm at 25 °C if controlling your
process with HI 9923 and HI 70442L with a value of 1500 ppm
(mg/L) value if working with HI 9935.
• Immerse the probe in the beaker ensuring that the holes on the
sleeve of the probe are completely covered.
• Stir the probe and tap it gently on the
bottom of the beaker to ensure that any
air bubbles trapped inside the sleeve
escape. Best results are obtained when
the probe is not too close to the walls of
the beaker nor lying on the bottom.
• Wait for the reading to stabilize. Adjust the "CAL SLOPE" trimmer
to display the same value as the
calibrations solution at 25 °C. For
example, with HI 7031L, you
should adjust the display to 1.41
mS/cm and with HI 70442 to
1500 ppm.
• Once the controller is calibrated to a solution by referring to its
value at 25 °C, all subsequent measurements are temperature
compensated to 25 °C. You can also obtain temperature compen-
sation to a different temperature reference point by calibrating
the meter to that value. For example, the conductivity and TDS
values of HI 7031L and HI 70442L at 20 C are 1.28 mS/cm and
1358 ppm, respectively. By adjusting the display to these values,
all subsequent measurements are compensated to a base tem-
perature of 20 °C.
Conductivity/TDS calibration is now complete.
SLOPE CAL
ALARM
ON
EC
mS
ZERO CAL
1.41
Min 7 cm
(2.8“)