Vaisala HUMICAP HMP155, User Manual, Page: 59 / 102

4.9 Pressure compensation commands
4.9.1 PRES and XPRES commands
Use the PRES command to set ambient pressure value for fixed pressure compensation.
If the value is changed frequently, use the
XPRES
serial line command. Its value is cleared to
0.0 at reset; if it is set to other than 0, it overrides the setting given with the
PRES
command.
In normal pressure conditions, the PRES command is not needed. If mixing ratio is
used in high altitudes, pressure changes increase the mixing ratio.
Use the serial line and do the following:
PRES a.aaaa
XPRES a.aaaa
Parameter Description
a.aaaa
Ambient pressure value (bar)
Example
>pres
Pressure : 1.013 bar ?
>
Example
>xpres
Pressure: 0.000 bar?
>
4.10 System commands
The system commands are used for setting the filtering level, checking the probe
configuration, listing available commands and possible error messages, and displaying the
probe software information.
Chapter 4 – Operation
57