Azbil Micro Flow MQV0005, Руководство пользователя

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6-3
Chapter 6. TROUBLESHOOTING
„
Troubleshooting guide
Observation Causes Remedy
Flow rate display does
not become zero even
with an actual zero flow
rate.
(Display is not
Off
even if the valve is fully
closed.)
• The device is installed on the vertical
(orinclined) piping.
• Condensation on sensor
• Zero point of sensor has deviated
• Foreign object on sensor
• Install in horizontal piping or use the
forced PV zero function (function setup
C-29
).
• Insert a mist trap upstream.
• Adjust the flow rate zero
• Ask for repair.
Flow rate does not
stabilize.
• Operating differential pressure range is
exceeded.
• Inlet pressure fluctuates greatly.
• Regulator interference
• Large pressure loss in piping (inlet pres-
sure fluctuates greatly according to flow
rate.)
• Check valve vibration.
• Operating differential pressure set-
ting (function setup
C-36
) does not
match the actual operating differential
pressure.
• Lower the primary pressure.
• Insert a regulator upstream.
• Change the regulator’s pressure setting
or increase the capacity of the pipe be-
tween this device and the regulator.
• Apply the instantaneous PV filter (func-
tion setup
C-23
).
• Use larger diameter pipe.
• Change the check valve to one having a
low cracking pressure.
• Adjust the operating differential pres-
sure setting to the actual operating
differential pressure or set "2" for the
operating differential pressure setup.
Poor accuracy • Temperature reference does not match
the reference flow meter.
• Regulator is vibrating slightly.
• Foreign object stuck on sensor
• Match the temperature reference.
(Change in
C- 19
in the function setup.)
• Change the regulator pressure setting.
• Ask for repair.
z
Flow rate zero adjustment
If a cause of the flow rate does not becoming zero in spite of an actual
zero flow rate is that the sensor's zero point has deviated, adjust the
flow rate zero point as follows:
(1) Press the
[DISP] key to display the instantaneous PV display.
(The
PV
and ("mL/min" on the MQV9020/9050)
L/min
lamps
light.)
(2) Set the operating mode to the fully closed mode, or set the set-
ting flow rate to zero, and fully close the valve.
(3) Continue pressing the
[ENT]
key in this state.
(4) After about 10 seconds,
0. cal
is indicated on the display. After
about one second, release the [ENT] key.
(5) The display changes to
0ff
. (Flow rate zero adjustment is
completed.)