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P118i Ultrasonic Flowmeter and Analyzer
Reversion: 3.0.0 Page 20 of 49
Ensure enough sonic coupling compound has been applied .Adjust the transducer position during the installation
to obtain the maximum signal strength.
Normal system operation requires signal strength over 65.0 from both upstream and downstream directions. If the
signal strength detected is too low, the transducer installation position and the transducer mounting spacing should
be re-adjusted and the pipe should be re-inspected. If necessary, change the mounting method to be Z method.
3.3.2 Signal Quality (Q value)
Q value is short for Signal Quality (displayed in Signal). It indicates the level of the signal detected. Q value is
indicated by numbers from 00 ~ 99. 00 represents the minimum signal detected while 99 represent the maximum.
Normally, the transducer position should be adjusted repeatedly and coupling compound application should be
checked frequently to ensure the signal quality can be detected as strong as possible.
3.3.3 Total Time and Delta Time
"Total Time and Delta Time", which displays in Window M6.04, indicates the condition of the installation. The
measurement calculations in the flowmeter are based upon these two parameters. Therefore, when "Delta Time"
fluctuates widely, so does the velocity and flow .This means that the signal quality detected is poor. It may be the
resulted of poor pipe-installation conditions, inadequate transducer installation or incorrect parameter input.
Generally, "Delta Time" fluctuation should be less than
±
20%. Only when the pipe diameter is too small or
velocity is too low can the fluctuation be wider.
3.3.4 Transit Time Ratio
Transit Time Ratio indicates if the transducer mounting spacing is accurate. The normal transit time ratio should
be 100+/-3 if the installation is proper. Check it in Window M91.
Attention
If the transit time ratio is over 100
±
3, it is necessary to check:
If the parameters (pipe outside diameter, wall thickness, pipe material, liner, etc.) have been
entered correctly,
If the transducer mounting spacing is in accordance with the display in Window M25,
If the transducer is mounted at the pipe
’
s centerline on the same diameter,
If the scale is too thick or the pipe mounting is distorted in shape, etc.
3.3.5 Warnings
(1) Pipe parameters entered must be accurate; otherwise the flowmeter will not work properly.
(2) During the installation, apply enough coupling compounds to the transducer to ensure adequate
contact with the pipe wall. While checking the signal strength and Q value, move the transducers
slowly around the mounting site until the strongest signal and maximum Q value can be obtained. .
(3) Check to be sure the mounting spacing is accordance with the display in Window M2.15 and the
transducer is mounted at the pipe
’
s centerline on the same diameter.
(4) If the signal strength is always displayed as 0.00 there is no signal detected. Thus, it is necessary to
check that the parameters (including all the pipe parameters) have been entered accurately. Check to
be sure the transducer mounting method has been selected properly, the pipe is not worn-out, and the
liner is not too thick. Make sure there is indeed fluid in the pipe or the transducer is not too close to a
valve or elbow. Ascertain there is not too much air or solids in the fluid, etc. With the exception of
these reasons, if there is still no signal detected, the measurement site has to be changed.
(5) Keep the flowmeter away from the electromagnetic interference area to ensure its proper operation..
(6) After completing the installation, power on the instrument and check the parameters and the result
accordingly.