Calibration and Measurement
Accurate conductivity measurement requires that you do not cross contaminate standards and samples. Before
using the Conductivity probe ensure it is rinsed with deionised water and blotted dry. Repeat this procedure when
transferring between al standards and samples.
1. Connect the conductivity cell into the Din connector on the top rear of the instrument.
2. Press the on/off switch. The display will light up.
3. The meter is now in the Conductivity mode. Press CAL to start calibration.
4. Insert the probe in the standard solution (swirl with the cell if required) and press READ
5. The auto endpoint indicator will show the progress of the calibration. When stable the meter will set itself to
the calibration value.
6. Remove the cell from the solution. Rinse with deionised water and blot dry.
7. Insert the probe into the sample solution (swirl if required) and press READ
8. The auto end point will freeze the display when the reading is stable
9. For further samples repeat from 6 above
Using different Calibration Standard solutions:
The QP481 comes complete with a 1413uS/cm standard solution. This standard is automatically set up in the menu.
To use a 12.88mS/cm standard do the following:
1. After switching the instrument on press the right arrow set up key.
2. In the PARAMETERS ADJUST screen scroll down to “Cal Standard” and press READ
3. The instrument now selects the 12.88mS standard. Scroll back up to CONTINUE and press READ.
4. Calibrate as above but using a 12.88 mS/cm standard solution.
5. To select a different standard in the PARAMETERS ADJUST screen scroll down to “Cal Standard” and press
READ Until “Custom Standard” appears. Press the right arrow Key.
Ensure the “ Entry” box is empty (select “Cancel” toclear a full box)
and input a Custom Standard in mS/cm.
6. Select “Enter” to finish. Then scroll up to Continue and press READ.
Using Conductivity Cells with different cell constants (K value)
The instrument default is set at K=1. The actual cell constant is calculated during calibration however some
applications require the input of a cell constant as the calibration. The most common cell constants for specialist
applications are K=0.1 and K=10. To set a cell constant:
1. After switching the instrument on press the right arrow set up key.
