AQ Elteknik AB Ultrasound Controller Manual 19
(starting the pump to empty the container). When liquid level drops to LS2, the relay opens
(stopping the pump).
Container with jacket
In a container with a jacket the small space between the container and the jacket is filled with
liquid to regulate the temperature of the inner container. This is a special case when a Level
Switch KS can use the Technique set to WR and Jacket set to the distance between the jacket and
container walls. Measurements will then be made on the inner container using the WR technique.
The space between the jacket and container must be filled with liquid.
CALIBRATION
Select CALIBRATION to calibrate the Level Switch. Each Level Switch must be calibrated after
installation. Calibration must be done both for liquid and for air. The order or the time between the
calibration of air and liquid is of no importance.
A new calibration has to be done if the Level Switch is moved and should be done if the
temperature or the liquid properties has changed significantly since the last calibration. To see
how well the Level Switch behaves at different temperatures or with a different liquid the
measurement data can be checked.
SHOW DATA
Select Echo DATA to show Edata: echo measurement data (echo strength) relative to ELiq. During
calibration it is set to be 100% with liquid. Efrq: shows the frequency (1, 2, 3 or 4). On the second
line threshold Ethd: is displayed. If Edata is higher than Ethd then liquid is detected. ELiq shows
calibrated echo strength with liquid (0,7dB units). Maximum is 100 and a value of 40 is a weak
echo. Eliq depends on the sensor and the container. Ethd is best if it is less than 40%. If higher
than 60% the difference between echo strength with liquid and air is too low.
Select WR DATA to show measurement data of the WR-technique. This screen shows first Wdata:
WR measurement data. Wdata is approximately zero when there is air. With Liquid it becomes
approximately twice Wthld. Wfrq: shows the frequency that has been chosen either manually or
automatically (1, 2, 3 or 4). The best frequency depends on the container wall thickness. On the
second line is Wthd: WR threshold which is the value of Wdata at which indication changes
between Air and Liquid. If Wdata is higher than Wthd then liquid is indicated. Wthd is set during
calibration to half the value of Wdata with Liquid. Wss: approximate signal (set at calibration) in
0,3dB units.
Select Auxiliary data to show raw data from the Level Switch. There are two pages A and B (press
MENU button to switch between them).
Select Test Level Switch to show test-data for the Level Switch when it is not attached to a
container. A value is shown for each Level Switch. If the Level Switch is correctly connected a
value between 0 and 70 should be shown. Then by pressing on the inner side of the Level Switch
with a finger this value should increase if the Level Switch is ok. A Level Switch wrongly
connected or unconnected shows a value higher than 100.
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