Vaisala DMT143 - Manual (Page 52)

USER'S GUIDE ____________________________________________________________________
50 ___________________________________________________________________ M211435EN-E
Set Pressure Compensation Value
The pressure of the measured system must be known for accurate
dewpoint and ppm measurement. The pressure compensation value has
been set at the factory according to the order form. You can view and set
a new value using the PRES command.
Command XPRES should be used if the value is changed frequently.
The value set using the XPRES command overrides the PRES value, but
it is not retained at reset. When the XPRES is set to 0, the last value set
with PRES is used instead.
NOTE It is enough to set an approximate pressure value (±1 bar) to meet the
accuracy specification of the DMT143.
PRES [pp.ppppp]
XPRES [pp.ppppp]
where
pp.ppppp = Absolute pressure (bar
a
) in the measuring point.
Range 0.001 ... 50 bar.
Example (set pressure compensation value to 3 bar):
pres 3
Pressure : 3.000 bar
The pressure conversion coefficients from other pressure units to bars is
given in the table below.
Table 10 Pressure Conversion Coefficients
From To bar
a
PaN/m² 0.00001
mmHg torr 0.001333224
inHg 0.03386388
mmH
2
O 0.00009806650
inH
2
O 0.002490889
atm 1.01325
at 0.980665
psi
a
0.06894757
For example: 29.9213 inHg = 29.9213 × 0.03386388 = 1.01325 bar
a.