There are two sets of RSSI values on the meter screen; these represent the signal strength received by the upstream and downstream probes. It is recommended that signal strength should be maintained at above 10% to ensure the normal operation of the system. If RSSI is found to be excessive or unstable, please refer to the following adjustment methods:
● Try to fine-tune the distance between the probes.
● Select a different site for mounting the probe.
● To confirm if there is any sediment in the pipe.
● Check whether the outer wall of the pipe is too thick with rust, oil, paint, or other substances. Afterwards, evenly apply more coupling agent.
● The signals from the two probes may not align. Try moving the probes slowly until the unit has a better RSSI value; check the probe for misalignment.
● After taking any of the above actions, be sure to double check whether the probe distance deviates too much; an excessive offset will result in flow measurement error.
● Check the setting in the MeterRx Peak Level settings. If the diameter of the pipe is large, the wire is too long, or other factors cause the RSSI to always be biased, try to adjust the relevant setting values. For related setting information, refer to the following instructions.
The Q value represents the received signal quality and can be regarded as an indicator of signal-to-noise ratio (SNR). The value is displayed at the lower right of the display interface. The value ranges between 0 and 100%. Under normal conditions, the Q value should be > 60%. The higher the Q value, the better the signal quality, and the more reliable the measured value. A Q value of less than 10% will not be measured. Try the following solutions:
● Sometimes the RSSI value is high, but a low Q value may be displayed due to slight distance, angle, or other errors in the probe. If the Q value is low, try to adjust the distance and angle of the probe slightly.
● If the pipe surface is rough, smooth it and confirm that the probe can completely adhere to the pipe surface with no gaps.
● If the coating provided by the coupling agent isn’t smooth, recoat to provide a smooth surface.
● If the pipe surface has impurities, dirt, or grime, the probe should be moved to another location.
● If surrounding equipment causes electromagnetic interference, change the installation location or strengthen shielding.
● If the fluid flow field is unstable, change the installation location.
● If the pipe diameter is too large, set up the probe in the Z configuration.
The seventh interface of the display output interface displays all values related to ultrasonic signal flight time (Time of Flight, or ToF). TOM (as shown in the picture) represents measured flight time, and TOS the calculated theoretical flight time. Ideally, the two values should be equal. If TOM/TOS yields a value that exceeds 100% ± 3%, the following steps should be taken:
● Check if the relevant setting parameters are correct. Check pipe material, pipe diameter, whether there is a liner, fluid type, and other relevant parameters. Check to ensure that the probe is mounted correctly.
● Check to ensure that the probe mounting distance is correct.
If> 100%, adjust upstream and downstream probes and bring them closer together.
If <100% adjust distance of probe, by moving them further apart.