If you are using an ultrasonic sensor, you should use a PLICSCOM puck to eliminate false echoes.
Fit the sensor to the roof of the tank pointing straight down, making sure that all sensory equipment is kept away from fuel at all times. Position the sensor in a raised housing if necessary.
Remove the cap from the top of the probe and install the PLICSCOM.
Press the OK button. You will see a menu. Scroll down from 'Basic adjustment' to the ‘Service’ menu option. Press OK.
The display will offer you the false signal suppression screen ('Change?'). This is where you can change its profile of false signals to ignore. Press OK.
The options available are to delete a profile, update an existing profile, or create a new profile. Since this is a new installation, scroll down to Create new and press OK.
You should see a screen ready for you to input the true distance you want the sensor to recognise.
Use the tank dipstick to measure the vertical distance from the base of the probe to the top surface of the liquid. This is the true distance you want the probe to recognise. Use the + button to input this measurement.
Press OK once.
The screen should show the message ‘Changing!’.
When this has finished press the escape button (ESC) to return to the menu.
To test that the process has worked, scroll down to Diagnostics and press OK.
You should see the heading Peak values and a list of data.
Press the > button to scroll through the next three screens.
The third screen should show you the echo profile, including the initial pulse and the various responses. This indicates a successful false signal suppression.
Press the ESC button to get back to the main screen, and remove PLICSCOM.
For more details refer to the manufacturer’s operating instructions