Mace HVFlo XCi, Product Manual

Page: 209 / 255

WARNING: If data such as that seen above is received, the operator should ensure
that the sensor is positioned correctly and monitor the site for any obstructions
close to the sensor. If no obstructions are located close to the sensor, the site may
be unsuitable for flow measurement with Doppler ultrasonic flow sensors.
The signal strength of received echoes on the real-time histograms, is a measure of the number of reflective
particles moving in the stream. Therefore, low signal strengths do not necessarily equate to poor velocity
readings. Relatively few particles may provide enough echoes for an accurate average velocity reading.
Furthermore, a histogram with a broad base will generally tend to have a peak with a lower signal strength. In
sites where it is suspected that there are relatively few reflective particles in the flow, the period in which the
XCi devices takes readings may require extending (see, Integration Period).
This real-time graph displays velocities captured by a sensor facing downstream. Although the amplitude
of the graph is negative the calculated average velocity is positive because the “Sensor orientation” has
been set to “Downstream” in the Doppler module configuration.
MACE XCi User Manual - 209 -