Aalborg Vortex Insertion - Manual (Page 75)

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8.2 Troubleshooting Guide
NO. INDICATION LIKELY REASON SOLUTION
1 LCD Display
remains blank
when unit is
powered up. No
response when
flow is introduced
from analog 4-20
mA. Power supply is bad
or polarity is
reversed. Measure voltage on pins 1 and 2 of the TB1 screw
terminal connector. If voltage is out of specified
range, then replace power supply with a new one.
If polarity is reversed (reading is negative) make
correct connection.
PC board is
defective. Return flow meter to factory for repair.
2 LCD Displays flow
reading, but 4-20
mA output signal
does not change
(always the same
or reading around
4.0 mA). Volumetric or Mass
Flow PV is no
assigned to
corresponding
4-20mA output Using Key Pad, navigate to Submenu L1 “Output
Menu” and select one of the Submenu L2 options:
“4-20mA Output1” or “4-20mA Output2”
(see paragraph 5.3.6.1). Make sure that parameter
“4-20mA Output1 Mode” or “4-20mA Output2
Mode” is set to Volumetric or Mass Flow.
External loop is open
or load resistance
more than 600 Ohm Check external connections to pins 1 and 2
(for channel #1), 3 and 4 (for channel #2) of the
TB3 screw terminal connector. Make sure the loop
resistance is less than 600 Ohm.
Flow output 4-20 mA
schematic is burned
out or damaged. Using Key Pad, navigate to Submenu L1 “Diagnostic
Menu” and select “Submenu DAC Outputs”. Record
the #1 and #2 counts values and consult the factory
with findings.
3 Fluid flows
through the Vortex
flow meter, but
LCD Display
reading and the
corresponding
4-20 mA flow
output signal do
not respond to
flow. The fluid flow rate is
below set Low flow
cut-off value.
Sensors or PC board
is defective. Check settings for Low flow cut-off value and make
required adjustment (see paragraph 5.3.7.6
“Submenu Meter Low Flow Cut Off”).
Using ESD precautions and hazardous area
precautions, remove the electronics enclosure
window cover. Remove electronics assembly unit.
Disconnect the vortex sensor connector from the
CPU board (the CPU board is the board with LCD
display) via cut out in the terminal board. Measure
the resistance from each outside pin to the center
pin (meter ground) – each should be open. Measure
the resistance from the center pin to the meter
ground (metal enclosure or pipe) – this should be
grounded to the meter. With the sensor connector
still disconnected from PCB, using Key Pad,
navigate to Submenu L1 “Diagnostic Menu” and
select “Pulse Frequency” or “PWM Frequency”
screen. Hold a finger on the metal part of the small
screwdriver and touch exposed outside pins of the
sensor connector on the CPU board. The meter
should read electrical noise, 60 or 50 Hz for
example. If it is true, re-install vortex sensor
connector back and check flow meter with flow
conditions. If necessary contact factory for
additional help.