User's Manual

Table Of Contents
Page 62 SITRANS LR260 (PROFIBUS PA) – OPERATING INSTRUCTIONS A5E32337685
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Parameters
2.2.4.2. TVT Hover Level
1)
Defines how high the TVT (Time Varying Threshold) curve is placed above
the noise floor of the echo profile, as a percentage of the difference between
the peak of the largest echo in the profile and the noise floor. When
SITRANS LR260 is located in the center of the vessel, the TVT hover level
may be lowered to increase the confidence level of the largest echo.
(For an
illustration of the TVT curve see
Before Auto False Echo Suppression on
page 63.)
2.2.4.3. Auto False Echo Suppression (AUTO ECHO SUPP)
Enables a ’learned’ TVT curve to be used in place of the default TVT curve.
(See Auto False Echo Suppression
on page 105
for an explanation)
a) Determine Range (the distance within which the learned TVT will
replace the default TVT). Measure the actual distance from the
antenna reference point to the material surface using a rope or tape
measure, and make allowances for the actual location of the device.
b) Subtract 2 m (6.56 ft) from this distance, and use the resulting value.
To use Auto False Echo Suppression via SIMATIC PDM:
c) Open the menu Device – Auto False Echo Suppression and set
Range. For more detail see
Auto False Echo Suppression
on page
44.
d) Select Learn. The device will automatically revert to On (Use
Learned TVT) after a few seconds.
To set Auto False Echo Suppression via the handheld programmer:
c. Go to Auto Suppression Range (AUTO SUPP RANGE)(2.2.4.4.) and
enter new value.
c. Go to Auto False Echo Suppression (AUTO ECHO SUPP)(2.2.4.3.).
Press RIGHT ARROW to open Edit Mode.
d) Select Learn. The device will automatically revert to On (Use
Learned TVT) after a few seconds.
1)
For an illustration, see
Before Auto False Echo Suppression
and
After Auto False Echo
Suppression
on page 63.
Values
Range: 0 to 100%
Default: 33%
Notes:
If possible adjust Auto False Echo Suppression parameters with an
empty or almost empty vessel.
Set Auto False Echo Suppression and Auto False Echo Range during
startup, if possible.
If the vessel contains an agitator, the agitator should be running.
Options
OFF Default TVT curve will be used.
* ON ’Learned’ TVT curve will be used.
LEARN ’Learn’ the TVT curve.