AQ Elteknik AB Ultrasound Controller Manual 11
Connecting the Air Sensor
The cable from the Air Sensor should connect directly to the Ultrasound Controller. Maximum
cable length depends on the Air Sensor, see Air Sensor manual. The cable screen must always
be connected (screened cable must always be used). Any unscreened part of the cable should be
no longer than 30mm. (The outer screen which exists only on FCS and FCP should not connect to
the Ultrasound Controller but may be connected to ground via screened cable glands). PAC also
needs a 50mm jumper cable to connect two terminals. To minimize the risk of electric interference
it is important that sources of interference like frequency inverters should use screened cables
between inverter and motor.
In an ex-installation, shielding aluminum plates must be
placed outside each group of zener barriers belonging to
each Ultrasound Controller, order number: Ex-
barriershield, see Air Sensor Ex manual.
SETTINGS
Through the SETTINGS-menu the parameters of the Air Sensor can be set.
Select SET TYPE to set the type of Air Sensor connected. This tells the Ultrasound Controller to
make the correct adjustments for this Air Sensor type.
Select SET DIAMETER to set it to the diameter of the connected Air Sensor or as close as
possible. This tells the Ultrasound Controller to make the correct adjustments for this Air Sensor
diameter.
Select SET SENSITIVITY to set the sensitivity. This determines how sensitive the Air Sensor is for
bubbles.
SENSITIVITY can be set to high, medium, low, very low and very very low.
At high sensitivity, a single bubble of approximately 2mm diameter can be detected.
At medium sensitivity, a single bubble of 3mm diameter can be detected.
At low sensitivity, a single bubble of approximately 10mm diameter can be detected. Low
sensitivity is achieved by requiring both detectors inside the Air Sensor to detect bubbles at the
same time. Many small bubbles together will be detected as if they were a single big bubble. Even
tiny (microscopic almost invisible) bubbles can be detected if there are many of them.
High, medium and low sensitivity are the normal measurements.
At very low and very very low sensitivity a different measuring technique is used. This technique
measures the presence of liquid or no liquid, making the Air Sensor very insensitive for bubbles.
Very low sensitivity does not work well for Air Sensors with diameter < 22mm. Very low sensitivity
measurements have temperature dependence and should not be used if there are temperature
variations of more than ±5ºC.
Select SET FILTER to set the filter-time. It determines how the measurement-data is filtered.
FILTER can be set to either integrate 1ms - 3s or delay 300ms - 10s.
Integrate means integrating (adding) the duration of each bubble. When the sum becomes higher
than the integrate time, air will be indicated. When liquid is next time indicated, the integration-
process starts over.
Delay means that air will be indicated when air has been continuously detected for a time longer
than the delay time.
Long FILTER delay and low SENSITIVITY is useful if some quantities of bubbles should be
undetected.
To Next Page
Loading...
Need help?
General