Information for accurate measurements
41
Information for accurate measurements
This chapter provides information on maintenance aimed at ensuring accuracy, such as
calibration methods.
Zero calibration Cal mode
Zero calibration is an operation adjusting the value of clean water to zero. The factors of zero
point fluctuations, such as dirt on the sensor head or the deterioration of light sources, can be
eliminated by zero calibration.
Note
z
Calibration cannot be performed in air. (Transmitted light in clean water is not the same as that in air.)
z
Remove all dirt on the tip of the detector prior to zero calibration.
z
Sterilize the sensor head with chlorine-based detergents if microbial adhesions are serious.
z
If the sensor head is wiped with alcohol, this may cause the zero point to drop because oil
contents are removed.
z
If a bucket is used during zero calibration, handle the bucket in the shade out of direct sunlight.
Q
Zero calibration procedure
Perform the following steps from the Meas mode.
Zero calibration can be performed for any working curves.
1.
Pull up the MLSS detector out of a sample and wash the sensor head in clean water.
2.
Pour water into the supplied calibration bottle or a bucket and soak the MLSS
detector in the calibration bottle or bucket.
3.
Be careful not to place the MLSS detector on the bottom, and hold the MLSS
detector in the water for 1 min.
4.
Put the converter in the zero calibration mode.
5.
Hold down the CAL key until CAL lights up.
6.
After a measured value has become stable, perform zero calibration. When the ENT
key is pressed, a numerical value blinks. Press the ENT key again at as low a value
as possible to complete zero calibration.
7.
After zero calibration is completed, return to the Cal mode.
8.
Hold down the ESC key to return to the Meas mode.
Tip
In the zero calibration mode, a negative indicated value is also displayed.
Hold down the
CAL key.
Blinking
Numeric value
