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TUF-2000F User Manual
4.3.6 N-method Installation
Rarely used method.
4.4 Installation Checkup
Through the checkup of the installation, one can: check the receiving signal strength, the signal quality Q
value, the traveling time difference of the signals, the estimated liquid speed, the measured traveling time of
the signals and the calculated traveling time ratio. Therefore, optimum measurement result and longer
running time of the instrument can be achieved.
4.4.1 Signal Strength
Signal strength indicates the amplitude of receiving ultrasonic signals by a 3-digit number. [00.0] means
there is no signal detected and [99.9] refers to the maximum signal strength that can be received.
Although the instrument works well if the signal strength ranges from 50.0 to 99.9, stronger signal strength
should be pursued, because a stronger signal means a better result. The following methods are
recommended to obtain stronger signals:
(1) Relocate a more favorable location, if the current location is not good enough for a stable and reliable
flow reading, or if the signal strength is lower than 60.0.
(2) Try to polish the outer surface of the pipe, and apply more coupler to increase the signal strength.
(3) Adjust the transducers both vertically and horizontally while checking the varying signal strength, stop at
the highest position, and then check the transducers spacing to make sure the transducers spacing is
the same as what the M25 shows.
4.4.2 Signal quality
Signal quality is indicated as the Q value in the instrument. A higher Q value would mean a higher Signal
and Noise Ratio (short for SNR), and accordingly a higher degree of accuracy would be achieved. Under
normal pipe condition, the Q value is in the range 60.0-90.0, the higher the better.
Causes for a lower Q value could be:
(1) Interference of other instruments and devices such as a powerful transverter working nearby. Try to
relocate the flow meter to a new place where the interference can be reduced.
(2) Bad sonic coupling for the transducers with the pipe. Try to apply more coupler or clean the surface,
etc.
(3) Pipes are difficult to be measured. Relocation is recommended.
4.4.3 Time Ratio between the Measured Total Transit Time and the Calculated Time
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