14 Ultrasound Controller Manual
With air in the Air Sensor, Ndata should be less than 15%. The threshold at which air bubble is
detected depend on sensitivity setting and type and size of Air Sensor (approximately at high
sensitivity threshold is 44% and at low sensitivity threshold is 27%).
Very Low Sensitivity Data
This page shows data from the very low sensitivity measurement. This measurement technique is
different from the normal measurement technique and is used only for very low and very very low
sensitivity settings. The two data on each line correspond to the two perpendicular measurements.
On the first line is VLdata showing the current measured ultrasound strength.
On the second line is VLthld showing the threshold. VLthld is measured and stored during
calibration. Liquid is detected when VLdata is > VLthld. For reliable operation VLthld should be > 5.
AUXILIARY DATA
This page shows unprocessed data from the Air Sensor. It can be used for troubleshooting when
contacting AQ Elteknik AB.
HELP
Select HELP to show information about how to connect the Ultrasound Controller.
Sound velocity in the Air Sensor
With sensitivity set to low, medium or high and with two liquids having different sound velocities in
the Air Sensor and with these liquids not well mixed, there can be false indication of air. The
sound is refracted due to velocity change, as it travels from one liquid to another. Setting longer
filter times and lower sensitivity can reduce such false indications of air.
Air Sensor TROUBLESHOOTING
Air or Liquid is indicated on the display but the relay does not change = RELAY setting is wrong.
Display shows:
Cal - Calibration should be done.
CalAir - Calibration Air should be done.
CalLiq - Calibration Liquid should be done.
set - Settings of TYPE or DIAMETER is missing
err 1 - No Air Sensor is detected. The reason for this can be wrongly connected Air Sensor, or
faulty Air Sensor.
err 2 - The relative signal with Air is too strong (at low, medium or high sensitivity). err 2 is shown
if NAir is higher than 21-25%.
The reason for high NAir can be:
Calibration of AIR has been done with liquid in the Air Sensor. Or Wrong settings of Air
Sensor Type or Diameter. Or electric interference. Or a faulty Air Sensor. Or calibration of
LIQUID has been done with liquid having lots of bubbles or particles attenuating the sound.
Electric interference will show itself as Ndata being unstable with Air in the Air Sensor. To
minimize the risk of interference it is important that sources of interference like frequency
inverters should use screened cables between inverter and motor. Also any unscreened part
of the cable between the Air Sensor and Ultrasound Controller should be short. If ex-barriers
are used, Ex-barriershields must be used especially if there is more than one Ultrasound
Controller.
err 3 - There is not enough signal difference between air and liquid (at very low or very very low
sensitivity). err 3 is shown if Very Low sensitivity threshold is not high enough for reliable
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