Vaisala HMP228 User Manual
Page 68
HMP228 Transmitters
Appendix 1: Serial commands
M210282en-A
62
MTIM
Setting the measurement integration time
MTIM nnn <cr>
nnn
=
number of cycles measured (4...255)
By lengthening the measurement integration time any stray changes in the out-
put can be filtered out: the transmitter calculates the average of a number of
measurement cycles defined by the user. The command can be given in two
ways:
>MTIM <cr>
Mtim : 4 ? 5 <cr>
or
>MTIM 5 <cr>
Mtim : 5
PRES
Setting the pressure for mixing ratio calculations
PRES pppp.pp <cr>
pppp.pp =
pressure (hPa)
The atmospheric pressure has an effect on mixing ratio. Therefore accurate
mixing ratio calculations can be achieved only when the ambient pressure is
taken into consideration.
When the command is given, the transmitter first gives the currently used
pressure; after this a new value can be entered or the old one acknowledged:
>PRES <cr>
Pressure : 1013.25 ? 1000.00 <cr>
When the currently used pressure is known, a new pressure can also be entered
directly:
>PRES 1010 <cr>
Pressure : 1010
NOTE
If the pressure setting is frequently adjusted, e.g. by
using an external barometer as a pressure input source,
the command XPRES is recommended.