Vaisala MMT330 - Manual (Page 101)

Chapter 4 _________________________________________________________________ Operation
VAISALA _______________________________________________________________________ 101
Data Filtering
The averaging data filter calculates an average over a certain period of
time. The lowest measurement noise is achieved with the extended
filtering. There are three filtering levels available.
Table 25 Filtering Levels
Setting Filtering Level
OFF No filtering (default setting).
STANDARD Standard filtering. Approximately 13 s moving average.
EXTENDED Extended filtering. Approximately 1 min average by
default, but configurable on the serial line.
Using Display/Keypad
1. Press any of the arrow buttons to open the Main Menu.
2. Select Measuring
by pressing the ► arrow button.
3. Select Filtering and press CHANGE to confirm your selection.
4. Select Off/Standard/Extended and press SELECT to confirm
your selection.
5. Press EXIT to return to the basic display.
Using Serial Line
Use the serial line command FILT to set the filtering level.
FILT [level] [extfactor]
where
level = Filtering level. The options are:
OFF (no filtering, default setting)
ON (standard filtering, approximately 13 s moving
average)
EXT (extended filtering, approximately 1 min average by
default but configurable by changing the extfactor)
extfactor = Weighted average factor for extended filtering level.
Range 0 ... 1, default 0.030.
In extended filtering mode, the output is calculated based
on the following formula:
[(new result * extfactor) + (old result * (1.0 - extfactor))]
This means that with extfactor value 1 the transmitter
will take only the latest measurement into account, but
with extfactor value 0.1 a new output is a combination of
the previous output (90%) and the latest measurement
(10%).