Filter
Top Products
22
Service Manual
Third edition, June 1997
• Distance is the distance from a separate ullage plug,
included, to the surface of the product in the tank. It is
the ullage plus the A-distance and is T/L-corrected.
• Filter center is the location of the center of the measur-
ing filter during the last sweep. This value is normally
very close to the ullage value. It can differ when the
surface is close to the bottom of the tank or close to a
disturbing echo.
• Time stamp is a counter that shows that the transmitter
is operating.
• T/L corr cog shows the correction value used to adjust
the ullage value from the TankRadar reference point to
a trim and list corrected value at the center of gravity in
the tank. The centre of gravity is in this case the center
of gravity of the product’s surface (COF) when it is at
the 98% filling (volume) in the tank.
• T/L corr plug is the trim and list corrected ullage at a
separate ullage plug (same as A-measure).
• Ampl prefilt is the amplitude of the incoming signal
from the transmitter before it has passed any filters.
• Ampl postfilt is the amplitude of the filtered signal.
This is normally the strength of the surface echo. Read
the Amplitude postfilt when using the Transmitter Test
Cable, see chapter 6.2.
• Noice threshold. Any echoes with amplitudes less than
the noice threshold do not interfere with the measure-
ment. This value is set to 350 mV as default. A normal
echo from an oil surface has an amplitude (Ampl
postfilt) of approximately 1500 to 2500 mV.
• Com err freq. Shows the frequency of communication
errors. Its value should be less than 10 (%/10). A larger
value could be an indication of, for example bad wiring.
The system should have been running for at least 15
minutes before this value shows a reliable figure. A true
indication of the communication performance is avail-
able after a few hours operation.
The Transmitter status are shown as check boxes.
• TX comfail indicates that the transmitter is not commu-
nicating. This produces an alarm on the alarm row.
• TX failure. No echo has been found. The transmitter is
ordered to wait for a minute, then it starts searching
again. The ullage values displayed are the last valid
values. The ullage is not updated as long as TX failure
is checked.