FPG8601™/VLPC™ OPERATION AND MAINTENANCE MANUAL
© 2007 DH Instruments, a Fluke Company
Page 18
2.8
COMPLETE DIFFERENTIAL PRESSURE EQUATION
The combination of all corrections along with the simplified pressure equation yields the complete differential
pressure equation for the FPG. An exploded view of all FPG calculations is detailed in Section 11.3.
Δ
P = K
cal.
. ( N +
δ
N
1
+
δ
N
2
+
δ
N
3
) / [A
eff.
(20°C) . [ 1+ (
α
p
+
α
c
) . (
θ
- 20 ) ]]
In gauge measurement mode, this differential pressure is equal to the gauge pressure of the FPG.
In absolute mode, the residual vacuum pressure measured by the vacuum reference sensor is applied to
the calculated differential pressure to obtain the absolute pressure of the FPG.
