ABB LST300 - Volume

42 LST300 | COMPACT ULTRASONIC LEVEL TRANSMITTER | LST300–EN REV. E
IMPORTANT (NOTE)
It is assumed in the following steps that the signal waveform
display is used.
If the signal waveform display is not available, the same
function can be performed by checking the process display
window to verify the measurement, and changing the True Echo
Index as shown in section “Selecting the True Echo Index (TEI)“.
8 In the waveform display, check whether the result of Tank
Profiling is as expected. In this example Echo 3 is selected
and the Instant Distance is
6.250 m . If this is the correct
target, no further setup is required.
IMPORTANT (NOTE)
Some echoes may appear small, but can cause false
measurements under certain conditions. LST300 compensates
for all possible conditions, and therefore may create false echo
windows when it does not look necessary in the current
measurement.
1. Ins 6.250m: Shows Instant Distance of the selected echo is 6.250 m
2. TEI 3: shows echo number 3 is selected as the true echo
9 As an example, Echo number 2 is assumed as the desired
echo in this step. Follow the steps in section “Selecting the
True Echo Index (TEI)” to change the True Echo Index to 2.
10 Check whether the result is as expected. The Instant
Distance is shown as 4.100 m in this example.
1. Ins 4.100m: Shows Instant Distance of the selected echo is 6.250 m
2. TEI 2: shows echo number 2 is selected as the true echo
11 To disable the True Echo Detection function, select Disable
Echo Detection from the “True Echo Detection” menu and
click OK.
IMPORTANT (NOTE)
Tank profiling data is lost when the Tank Profiling function is
disabled.
Volume
Volume output is used in sitiuations where a volume output is
desired, instead of the level. LST300 has 32 points allowing the
operator to plot a volume to level chart. This chart is usually
provided by the tank manufacturer. It is also possile to calculate
custom tank volumes using dimensions from drawings.
Common tank shapes include:
• Flat base tanks
• Cone base tanks
• Half sphere base tanks
• Sloped base tanks
• Horizontal cylinder tanks
• Tanks with angles between sections