Chapter 4 ________________________________________________________________ Operation
VAISALA _______________________________________________________________________ 55
Using Serial Line
Pressure 3h trend and tendency reading is also available through serial
line. Key in the lines below:
>form "trend=" P3H " " "tend" A3H #RN
>
For more information on the Form command, see section
Quantities and Units on page 76
Missing Trend
When the pressure tendency has not yet been calculated, that is, the
device has been powered-up less than three hours ago, the PTB330
barometer outputs a code "*" . The absence of the pressure trend is
indicated in a similar manner, too.
Graphic History
The graphical display shows the data trend of the selected quantities,
one at a time. The graph is updated automatically while measuring. Use
the following functions in the graphical display:
-
Press the
NEXT
button to have the trend graph and max/min graph
in turns and browse through the quantities selected for display.
-
Press the
EXIT
button to return to the basic display.
8
=
Steady or increasing, then decreasing; or decreasing then
decreasing more rapidly; atmospheric pressure now lower
than three hours ago
Source: The World Meteorological Organization (WMO) publication
Manual on Codes Vol. 1.1, International Codes, Part A -
Alphanumerical Codes, 1995 Edition, WMO - No. C, Code Table
0200:a.
