- 15 -
times in parameter setting P2, and read the average value each time to improve the
measurement accuracy. Compare the maximum and minimum values at the same time. If the
difference is too large, it means that the measured value is not reliable, the solution may be
unstable or there might be other factors affecting the measurement. You need to check the
root-cause and measure again. For rapid-settling or continuously changing solutions, set
continuous measurement for 10, 15 or 20 times.
5.4 Notes for Measurement
a)
Keep the sample stable
: After the vial is placed into the sample cell, it is recommended to wait for
1 to 2 minutes before calibration, as the solution will experience some shaking when the vial moves,
which may result in inaccurate measurements.
b)
Sample Vial cleaning requirement
: Sample vial must be rigorously cleaned and free from
smudges and scratches. When wiping, user should grip the cap and bottom to avoid leaving
fingerprints on the surface of the vial. Its surface should be applied with a drop of silicone oil be
wiped with a micro-fiber cloth. After that, please clean with filter paper or high-quality tissue paper.
See section 4.1(c) for details.
c)
Mixing and Degassing
: Samples should not be vigorously shaken or vibrated. It is recommended
that users gently shake the sample vial to make solution evenly distributed. Air bubbles in solution
will cause big error to turbidity measurement. So the vial should be left stand still for 2 to 5 minutes
to eliminate potential air bubbles before measuring. But mixing and degassing simultaneously is a
difficult process to handle, especially for solution with precipitates, which requires some operating
experience or make some limits in test conditions. For example, limit the mixing condition and
waiting time for degassing to be the same before comparing measurements.
d)
Other Requirements
⚫
On the premise of ensuring evenly distributed samples, sample solution should be measured
immediately to prevent temperature changing and precipitates from affecting measurements.
⚫
Avoid sample dilution for measurement as much as possible.
⚫
Avoid operating under direct sunlight.
⚫
Do not pour solution into the sample vial holder. Sample vials must be used for measurement.
⚫
Please do not wash the sample vial holder as this may damage its optical structure.
6
PARAMET ER S ET UP
6.1 Operation
Press to enter parameter setup
mode → press or to switch P1-P2-...P9 → press
to enter each
parameter → press or to make changes → press to confirm → press
to return to measurement mode.
