Siemens SITRANS LG270 Operating Instructions Manual page 37

False signal suppression
PBD-51041506
The following circumstances cause interfering reflections and can
influence the measurement:
•
High mounting sockets
•
Vessel internals such as struts
Note:
A false signal suppression detects, marks and saves these false
signals so that they are no longer taken into account for the level and
interface measurement. We generally recommend carrying out a false
signal suppression to achieve the best possible accuracy. This should
be done with the lowest possible level so that all potential interfering
reflections can be detected.
Proceed as follows:
Select first if the probe is covered or uncovered.
If the probe is covered, enter the actual distance from the sensor to
the product surface.
All interfering signals in this section are detected by the sensor and
stored.
Keep in mind that with covered probe only false signals in the uncov-
ered area of the probe are detected.
Note:
Check the distance to the product surface, because if an incorrect
(too large) value is entered, the existing level will be saved as a false
signal. The level would then no longer be detectable in this area.
If a false signal suppression has already been created in the sensor,
the following menu window appears when selecting "False signal
suppression":
The instrument carries out an automatic false signal suppression
as soon as the probe is uncovered. The false signal suppression is
always updated.
The menu item "Delete" is used to completely delete an already cre-
ated false signal suppression. This is useful if the saved false signal
suppression no longer matches the metrological conditions in the
vessel.
SITRANS LG270 - Operating Instructions
37