Level Calibration - ABB LMT Series Operating Instruction

Magnetostrictive level transmitters foundation fieldbus
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L M T 1 0 0 A N D L M T 2 0 0 | M A G N E TO S T R I C T I V E L E V E L T R A N S M I T T E R S | F F O I/ L M T 1 0 0/ 2 0 0/ F F - E N R E V. A

Level Calibration

The LMT Series is a digital transmitter with no routine
calibration or reconfiguration required If a recalibration is
required, this can be done using the menu driven HMI display,
push button and Hand-held terminals
The most important term to understand and master the
calibration process is the Sensor Value (SVL) SVL can be seen
from two perspectives:
• Technical – SVL is the output parameter of the factory trim,
which gets mapped to the propagation time
• Practical – The SVL is the Raw Level, which is the level before
any user specific calibration is applied to the instrument Its
value always increases in the direction to the tip of the probe,
independently of the mounting orientation
Figure 34 Bottom & Top Mount Charts
In other words, the SVL can be seen as the level output of the
instrument based only on the factory trim After the factory
trim the SVL at any given point on the probe will remain
unchanged for the life of the instrument (unless trimmed again
at later time) It is not affected by any level calibration, offset or
linearization applied by the user
Note that Calibration Point 00 is always located above
Calibration Point 01, which means Point 00 always corresponds
to a higher level value than Point 01
Figure 35 Calibration Points
By default, after the trim the SVL and LVL are aligned at the
calibration points 00 and 01 matching each other values, but
during the Level Calibration SVL can be mapped to different
Level Values (LVL) that don't violate the validation rule for Level
calibration: The LVL span must be within ±5% the SVL span
LMT calibration through HMI
STEP 1:
From the Level Information screen, press
Access Level menu
STEP 2:
Press
or
to navigate to Advanced
Press Select
to switch to the

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