Aalborg DPM Series Operating Manual page 101

NO. INDICATION
4 OLED Display reading
does correspond to the
correct flow range, but
0-5Vdc output signal
does not change
(always the same
reading or around
zero).
5 OLED Display reading
and 0-5Vdc output
voltage do correspond
to the correct flow
range, but 4-20 mA
output signal does not
change (always the
same or reading
around 4.0 mA).
6 Calibration is off (more
than ± 0.5 % F.S.).
7 OLED reading for Mass
Flow, Volumetric Flow,
Gas Pressure or Gas
Temperature is
flashing.
8 Gas flows through the
DPM, but OLED
Display reading and
the output voltage
0-5Vdc signal do
not respond to flow.
LIKELY REASON
Output 0-5Vdc
schematic is burned
out or damaged.
Analog flow output
scale and offset
variable are
corrupted.
External loop is open
or load resistance
Output 4-20 mA
schematic is burned
out or damaged.
DPM has initial zero
shift.
Measured parameter
exceeds the range of
the corresponding
sensor in the
instrument.
PC board or sensor
is defective.
The gas flow is too
low for the particular
DPM model.
Differential Pressure
Sensor or PC board
is defective.
...continued...
9
SOLUTION
Return DPM to factory for repair.
Restore original EEPROM scale
and offset variable or perform
analog output recalibration (see
Section 6.4. 3.6).
Check external connections to pins
6 (+) and 4 (-) of the D-connector
MiniDIN. Make sure the loop
Return DPM to factory for repair.
Shut off the flow of gas into the
DPM; ensure gas source is
disconnected and no seepage or
leak occurs into the meter from
either port). Wait for 1 min. with no
flow condition and perform Auto
Zero calibration Procedure
(see Section 6.4. 4 "Zero
Calibration").
Reduce the value of the flashing
parameter within specified limits.
For example, reduce Mass Flow
rate below 133% of instrument full
scale range. NOTE: When at
least one parameter is flashing
on the display, the value of this
parameter and mass flow
reading cannot be considered
accurate.
Return DPM to factory for repair.
Check maximum flow range on
transducer's front panel and make
required flow adjustment.
Return DPM to factory for repair.