Event marks can be set, for example when the sample is injected, and are displayed as
spikes on the chart recorder. The spikes are 10% of the full scale of the chart recorder
which corresponds to 0.1 V.
Press the
event mark key to insert an event mark.
Setting averaging time
(filtering noise)
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 may be distorted. Because of this
the averaging time should be as short as possible, see the table below. On delivery the
averaging time is set to 2.56 s.
Follow the steps below to set the averaging time.
Step
Action
1
Select menu
Set Averaging Time, press OK.
2
Use the arrow keys to set the value. Use the fixed values between 5.12
seconds and 0.08 seconds.
Averaging time (s)
Time constant (s)
(approximate)
Min. peak width at half
height (s)
5.12
2.0
32
2.56
1.0
16
1.28
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
5 Operation
5.8 Setup menu
54
Monitor UVis-920 Operating Instructions 29055049 AF
Summary of Contents for Monitor UVis-920
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