PPCH-G™ OPERATION AND MAINTENANCE MANUAL
© 2007 DH Instruments, a Fluke Company
Page 126
PPCH-G Q-RPTs calibrated in gauge measurement mode by applying gauge reference
pressure values should be used in gauge mode only (see Sections 3.3.3
PRINCIPLE, 5.2.5).
•
Able to supply the recommended sequence of pressure points in the range to be
calibrated:
See Section 5.2.4 for information on the recommended calibration point
sequence for PPCH-G Q-RPTs.
5.2.3
SET-UP AND PREPARATION
To set-up and prepare the PPCH-G for calibration of an internal Q-RPT:
Set the PPCH-G on a stable surface near the calibration standard at a height as close as
possible to the calibration standard’s reference height. Consider the connections that
may need to be made to the rear panel and access to the front panel display and keypad.
Connect the calibration standard output to the PPCH-G rear panel
TEST
port (DH500 F).
DH500 is a gland and collar type fitting for 1/4 in. (6.35 mm) coned and left hand threaded
tube. DH500 is equivalent to AE F250C, HIP HF4, etc. DO NOT USE INCORRECT FITTINGS;
DAMAGE TO THE FITTING AND DANGER TO THE OPERATOR COULD RESULT.
Turn OFF the PPCH-G VENT (see Section 3.1.3).
Use
[SETUP]
,
<6control>
,
<1mode>
to set a pressure control mode other than
<PG>
(see Section 3.4.6.2). . The control character in the middle of the bottom line of the
display must be other than
<P>
.
5.2.4
RECOMMENDED CALIBRATION POINT SEQUENCE
Calibration adjustments to PPCH-G Q-RPTs are made by adjusting calibration coefficients,
PA and PM (see Section 5.2.1.1). To adjust these coefficients to optimum values giving the
best results over the Q-RPT’s complete operating range, specific calibration point sequences
are recommended.
Prior to running the calibration point sequence, the Q-RPT should be exercised by setting full
scale pressure, dwelling at full scale pressure for 5 minutes, returning to atmosphere
(vented), dwelling for 5 minutes.
A dwell time after setting the pressure of 90 seconds before taking data at each point is
recommended.
PPCH-G must be in a pressure control mode OTHER THAN piston gauge mode when it is
calibrated. The control character in the middle of the bottom line of the display must be other
than <P> (see Section 3.4.6.2).
It is not required that the calibration pressure standard apply precisely the nominal pressure
value of each calibration point as long as the exact value of the applied pressure is known. Best
results are obtained if the actual applied pressure is within 2 % of the nominal point definition.
