Calibrating The Conductivity/Tds/Salt Probe; Calibrating An Oxygen Probe - General WK2017SD User Manual

CALIBRATING THE CONDUCTIVITY/TDS/SALT PROBE

The following procedure is sufficient to calibrate the supplied conductivity/TDS/salt probe
so it accurately measures all three parameters.
1. Obtain the correct standard conductivity solution(s) for the full-scale range(s) you
expect to use. For example, if you expect to measure conductivity values using a full-
scale range of 2 mS, use a 1.413 mS standard conductivity solution. For measurements
within the 200 uS full-scale range, obtain and use an 80 uS standard solution.
2. Plug the probe into its dedicated socket on the top of the meter (callout 1-15 of
Fig. 1). Then power on the meter and push the M button (which has the word "MODE"
stenciled above it) until the display shows the term "Cd".
3. To perform the calibration, immerse and shake the head of the probe in the
standard solution. The display will show its conductivity in units of uS or mS.
4. Once a value is displayed, use two fingers to press the REC/ENTER and HOLD/ESC
buttons simultaneously.
5. When this screen appears, release both fingers. Then press the
REC/ENTER button. The display will then switch into a two-level
(upper and lower) mode that looks like this:
6. Press the M or L button to raise or lower the measured value until it matches the
standard conductivity value.
7. Complete the calibration procedure by pressing the REC/ENTER button.
If you expect to make conductivity readings using other full-scale ranges, you should repeat
this calibration procedure using other standard conductivity solutions of appropriate
strength. If you do, General advises performing the above procedure (for a 2-ms full-scale
range) first.

CALIBRATING AN OXYGEN PROBE

An optional oxygen probe must be calibrated before you use it for the first time, and again
after a long period (weeks or months) of sitting idle. General also recommends calibrating
an oxygen probe before making any measurements that must be extremely precise.
Before beginning the calibration procedure, make sure that the oxygen probe is full of fresh
electrolyte. Use the following steps—while referring to Fig. 3 below—either to fill the probe
with electrolyte or to replace old electrolyte with fresh electrolyte.
1. Unscrew the probe head from the probe handle
2. Empty and dispose of any residual electrolyte from the probe head's reservoir
3. Pour fresh electrolyte into the reservoir
4. Screw the probe head back into the probe body
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