6. Other Conditions

A. The measured value jumps sharply Under some conditions, when the fluid flow rate is fast the measured value may jump sharply. This may be caused by a poor startup of the ultrasonic signal waveform as shown in the following figure:

The figure on the left shows poor signal waveform startup. The wave heights near the trigger level are all similar, a phenomenon which can easily lead to a trigger time point error, which in turn leads to a jump in the value due to the resulting time difference calculation error. The correct signal waveform should be as shown on the right, with sufficient drop height between waves. Possible causes of a poor initial waveform are shown below:

1. Z-type configuration : Probe axis is off-center. Adjust the probe position.

2. V type configuration : Probe distance error. Adjust the probe distance according to the signal strength.

3. V-type configuration: Probe axis and pipeline are not parallel. Adjust the position.

It is also possible that in the initial settings, the pipe’s outer diameter setting is larger than the actual diameter. If this is the case, re-measure and adjust the setting, then fine-tune the configuration according to the displayed probe distance. If there is still a jump after this operation is completed, then the Meter → 16.Anti-noise​ function in the setting options can be switched on to control the problem.