Regal RH40, Руководство пользователя

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§3.4.C Total Transit Time and Delta Time
The total transit time (or traveling time) and the delta time are both displayed on menu window M23.
This window can be accessed by pressing the following series of keys:
M 2 (Diagnosis) M23 (Transit Time)
See section §3.4.D for more details. These values are the primary data used by the instrument to calculate
the flow rate. They are the most important values calculated by the flow meter . The measured flow
rate will vary as the total transit time and delta time vary. Therefore, the total transit time should remain
stable or fluctuate only very slightly. The device will adjust for any variance on its own until it is
stable.
The delta time normally varies less than 20%. If the variation exceeds 20% in either positive or
negative direction, there may have been errors in the installation of the transducers. The user
should examine the installation site for any apparent problems. The following list shows some common
examples of installation errors that cause inaccuracies in measurement:

There may be insufficient couplant between the transducers and the pipe surface.

The transducers may not be spaced correctly or may have been placed in a non-favorable
location. Either of these issues will cause weak signal strength and quality .

The pipe may be only partially full or there may be air bubbles. If this is the case, the logarithm
used to calculate the flow rate will not yield accurate readings. Make sure that the pipe is
completely full and that there are no air bubbles in the liner.

The wall thickness values may be incorrect . The error may have resulted from corrosion on the
pipe. Use the Z-method of installation or move to a more favorable location.
§3.4.D Transit Time Ratio
This ratio is used to check the quality of the transducer installation. It also verifies whether the entered
pipe parameters are consistent to their actual values. If the pipe parameters are correct and the transducers
are installed properly, the transit time ratio should be in the range of 100±3 . If this range is not met, the
user should verify the following:

The entered pipe parameters are correct

The actual spacing of the transducers is the same as or close to what is shown on window S1, Step 5
(see Section §2.6)