6. TROUBLESHOOTING
Page 143 © 2002-2007 DH Instruments, a Fluke Company
SYMPTOM PROBABLE CAUSE SOLUTION
There is a restriction in the test connection
between the PPC3 and the test or the PPC3,
the RPM4 and the test.
Remove the restriction to allow free flow
between the PPC3, the RPM4 (if present)
and the test. 2.3.8
Pneumatic control module needs to be
reconfigured.
Reconfigure control module after all other
possible control issues are considered. 5.5
The volume connected to the TEST(+) port is
too small.
Add volume to the system connected to the
TEST(+) port. 1.2.3
A filter in the PPC3, the SPLT or an
accessory is dirty and causing a restriction.
Clean and dry or replace the filter element.
Excessive leak present in system.
Correct internal or external leak or increase
hold limit. 3.3.9, 3.4.6
Poor pressure control characterized
by excessive overshooting/
undershooting and/or “hunting”
around target.
Test volume too small.
Increase test volume. Consider use of
DVU (Dual Volume Unit) if Q-RPT is
G15K or BG15K. Consider
reconfiguration of pneumatic module
after all other possible control issues
have been evaluated. 2.3.8.2, 5.5
Poor pressure control characterized
by minor overshooting.
Some overshooting is part of normal
operation to speed up pressure stabilization.
Check whether overshooting is within
normal limits. Objectively evaluate
significance of overshoot relative to DUT
span and specifications. Increase test
volume.
Poor pressure control characterized
by very slow slew rate.
Test volume is too large. Severe restriction
in a test line.
Reduce test volume if slew rate is
unacceptable. Remove restrictions in
line connected to TEST(+) port.
Poor pressure control. Unstable or incorrect pressure supply.
Connect regulated pressure supply set to
correct supply pressure to SUPPLY port.
2.3.5
Poor pressure control and
measurement.
The PPC3 and/or the connection to the test
system is contaminated with liquids.
Purge and clean affected systems. Consider
use of Self-Purging Liquid Trap. Contact
DHI Authorized Service Provider if PPC3
is contaminated internally. 2.3.8.1, Table 31.
Disagreement between two Q-RPTs
in system appears excessive.
Difference is actually within tolerance and
acceptable disagreement. Note the Internal,
Hi transducer may be a utility sensor which
has a much wider tolerance than a Q-RPT.
Compare differences observed to
tolerances on Q-RPT and/or utility sensor
measurements. 1.2.2.1, 1.2.2.2
Apparent inaccurate pressure
control/measure and little or no
response from Q-RPT or utility
sensor:
Reference transducer destroyed by
overpressure.
Contact DHI Authorized Service Provider.
Table 31
Apparent inaccurate pressure
control/measure when using
Internal, Hi (IH) RPT.
The IH transducer is a utility sensor, not a Q-
RPT.
Operation is normal for lower specifications
of utility sensor.1.2.2.2
Incorrect pressure units and/or measurement
mode (gauge or absolute).
Set desired pressure units and/or
measurement mode. Consider reference
temperature if unit is inWa. 3.3.2, 3.3.3
Q-RPT calibration coefficients have been
altered.
Check and correct calibration coefficients if
needed. 5.2
Apparent inaccurate pressure
measurement/control.
AutoZ has been run and turned ON with an
incorrect standard for zero.
Check value of P
offset
. Rerun AutoZ with a
valid reference. 3.5.1
Apparent inaccurate pressure
measurement/control and <h> is
displayed on top line of screen.
An unplanned “head” correction is active or
head height or gas is incorrect.
Operation is normal. Remove or change
“head” correction. 3.3.7
System is vented but does not indicate zero
because measurement mode is absolute.
Check measurement mode setting and
current value of atmospheric pressure if
absolute. 3.3.3
VENT port is plugged. Open VENT port to atmosphere.
Will not vent.
Vent valve not operating.
Contact DHI Authorized Service Provider.
Table 31
Will not vent while purging. Stuck at
pressure during purging.
Purge function is not activated, Purge
function is activated but no SPLT is
connected or SPLT valve is not operating.
Activate SPLT; correct SPLT connection or
repair SPLT exhaust valve. 3.5.7.4, 2.3.8
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