User manual

3.11 Filtering noise in the UV signal
To filter the noise in the UV-signal, a moving average filter is used.
The averaging time is the time interval used for calculating the
moving average of the absorbance signal. A long averaging time will
smooth out noise efficiently, but it will also distort the peaks. Peaks
narrower than the minimum peak width value according to the table
below may be distorted. Because of this, the averaging time should
be as short as possible. On delivery, the averaging time is set to
1.3 s.
1 From main menu 1, turn the dial six steps clockwise and
press
OK twice.
2 Select Setup UV and press OK.
3 The menu
Set Averaging is displayed, showing the current
set averaging time. Press OK.
4 Set the desired value and press
OK. Values allowed are 0.02,
0.04, 0.08, 0.16, 0.32, 0.64, 1.3, 2.6, 5 and 10 s.
Averaging time (s) Corresponding Min. peak width
time constant (s) at half height (s)
(approximately)
10.0 5 50
5.1 2 32
2.6 1 16
1.3 0.5 8.0
0.64 0.2 3.2
0.32 0.1 1.6
0.16 0.05 0.8
0.08 0.03 0.5
0.04 0.01 0.2
0.02 0.01 0.1
In UNICORN, the averaging time is set with the instruction
AveragingTime in System Control:Manual:Alarm&Mon
3.12 Changing UV flow cell
The flow cell can be changed when required, for example, from
2 mm to 5 mm when the sensitivity of the measurement must be
increased due to a small amount of sample being applied, or from
5 mm to 2 mm when a lower sensitivity is desired, due to output
signal limitation.
See section 2.3 Installing the optical unit, sub-section Flow cell
installation.
Set Averaging
(1.3s) 0.64
Set Averaging
(1.3s)
Setup
Setup
Monitor UPC-900
User Manual 18-1125-55 Edition AE
19
Operation 3