Maintenance
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Maintenance
This chapter provides information on maintenance aimed at ensuring accuracy, such as
calibration methods.
Calibration
Zero calibration
Zero calibration is an operation that adjusts the value of clean water to zero.
The following calibration method is recommended, depending on the degree of turbidity.
When low turbidity water (such as tap water or swimming pool water) is measured, the
turbidity resulting from air bubbles and matter adhering to wall surfaces may make it difficult to
perform calibration by accumulating zero water. For this reason, it is recommended that you
perform zero calibration while successively running zero water filtered with an ultra filter.
Run zero water successively and check that the indication has been stabilized. Then, perform
zero calibration when the value of the turbidity reaches the lowest level.
Note
If the inside of the cell is filled with air, zero calibration cannot be performed.
When running zero water, be careful of the formation of air bubbles.
Turbidity might increase due to contamination in the piping path.
For sample water with a high salt content, it may be necessary to use filtered water of the same
salt content as zero water.
Zero calibration procedure
Perform the following steps in the meas mode.
Zero calibration can be performed commonly for any turbidity standard substances.
1.
Remove the automatic cleaner, then clean the cell of the detector adequately with a
brush.
2.
Close the valve beneath the detector, and pour zero water from above into the cell.
Or, switch the lines and run zero water successively.
If air bubbles are formed in zero water, reattach the automatic cleaner or the lid, then
pressurize the detector by adjusting the outlet valve.
3.
Wait until the indication is stabilized.
If the turbidity fluctuates, the cleaning was insufficient.
4.
Hold down CAL until the HOLD lamp lights up to enter the zero calibration mode.
Once the measured value is stabilized, perform zero calibration.
5.
Press ENT. The numerical value starts blinking. Press ENT again at the lowest value
to complete the zero calibration.
Hold down
