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<4. SETTING PARAMETERS>
4-5
IM 12E01B30-02EN 2nd Edition : June 09 , 2021-00
F6-12E.ai
Time
Turbidity
Air denoising hold time
Denoising release
time
In Process
A > Air noise detection value
A: Difference between the current signal and the previous signal
A < Air noise detection value
Turbidity Signal
Intake Cycle
Function restarts
Air Bubbles Detected
(No turbidity signal is taken
during the process)
Figure 4.1 Air denoising function
[How to Set Each Parameter]
a. Air noise detection value
Air noise detection value is used to determine whether a reading is a spike due to air bubbles or
dust and is defined as a turbidity value in NTU. (The ratio of the sensitivity correction factor is also
calculated automatically.)
For the Air noise detection value check, a pre-averaging turbidity value is used. To determine the
Air noise detection value, it may be needed to know the degree of fluctuation in pre-averaging
turbidity signals. Set the damping time constant to 0 to give turbidity readings directly without
averaging. Check readings to know the degree of fluctuation. Generally, the Air noise detection
value is set to a value greater than the fluctuation.
b. Air denoising hold time
When a signal exceeds the air noise detection value, the turbidity value is held for a specified Air
denoising hold time. The Air denoising hold time should be long enough for removing air bubbles
and dust in the flow cell. Normally, air bubbles and dust will run off the flow cell or disappear
within a short time (in a few seconds). In practice, first set the Air denoising hold time to a shorter
time, and then increase it if the function does not work satisfactorily.
c. Denoising release time
After the Air denoising hold time has elapsed, the turbidimeter gives readings without any
processing for a specified Denoising release time to verify that no fluctuation occurs in turbidity
readings. The time count begins after the Air denoising hold time. It is unlikely that air bubbles or
dust occur consecutively. Therefore, the Denoising release time may not need to be too short.
If the Denoising release time is set too short, the response is delayed when a sudden change in
turbidity actually occurs. First set the Denoising release time slightly longer. If something is wrong
with the behavior, shorten the time.
Instructions for Use
Be careful when using the function since the following restrictions apply.
(1) The function works only in measurement mode. As soon as the mode is changed, the Hold
or Denoising release timer is reset and the function stops.
(2) During an Air denoising hold time period, both turbidity readings (including communication
data) and analog outputs are held. During the hold time, is displayed on the HMI.
Contact output doesn’t work by this function.
(3) The function does not run for approximately 5 seconds right after the turbidimeter is turned
on.
(4) If the turbidimeter is turned off then on again while the function is running, the timer is reset.