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INF-TN1FSH-E
6.2.3. Measurement value error
State Cause
Remedy
•
Connection
between main unit and
sensor (Upstream sensor and
downstream sensor are reversed.)
Connect properly
The reading appears with
“
−
” (minus).
•
The fluid is flowing as shown by the
reading.
•
The length of linear pipe section is
insufficient.
Move the sensor to the place where the length
of 10D can be assured on upstream side and
5D on downstream side.
•
There is an object nearby that
interferes with the flow such as a pump
or valve.
Mount the sensor keeping the distance of at
least 30D.
The reading fluctuates
abnormally even if the flow
rate is kept constant.
•
The flow is actually pulsing.
Increase the response time by damping setting.
Ultrasound waves cannot be transmitted, which causes the measurement to be held.
1. Improper installation
The reading does not change
even if the flow rate
changes. (Error display on
LCD)
•
Improper piping specifications
•
Sensor is mounted on welded
section.
•
Improper sensor spacing
•
Insufficient filling of silicon at the
time of sensor mounting
•
Improper connection of sensor
cable
Check and remove the sensor, apply silicon
filling material again, and mount the sensor
in a position slightly deviated from the
original position.
Improper sensor mounting
•
Spacing
•
The sensor is coming off the pipe.
•
Mount the sensor, allowing sufficient
sensor spacing, in parallel with the pipe.
•
Attach the sensor firmly on the pipe.
2. Problem of piping and fluid
!
Pipe is not filled with fluid.
Find a place in the same piping line where
the pipe is filled with fluid, and attach the
sensor there.
•
Mount the sensor at the place lowest in
the piping line.
!
Air bubbles are mixed in.
If the reading becomes normal when
the fluid is stopped, the cause is
mixing in of air bubbles.
If the sensor is mounted immediately
after the valve, cavitation induces
the same phenomenon as mixing in
of air bubbles.
Prevent air bubbles from mixing in.
•
Increase the level of the pump well.
•
Check the sealing of pump shaft.
•
Fasten the negative piping flange.
•
Take measures to prevent the fluid from
falling down into the pump well.
Move the sensor to a place where the fluid
does not contain air bubbles.
•
Inlet side of the pump
•
Upstream side of the valve