Rosemount Model 3095 Multivariable
™
Level Controller
4-10
PERFORM A LEVEL TRIM
Performing a level trim is recommended for all field installations. Level
trim can be done in OOS and MAN mode; it cannot be done in AUTO
mode (see page 4-2).
The level trim process allows the user to calibrate the level calculation
against the actual tank level as measured with a sight glass or other
visual reference. A level offset trim is normally done at or near the
lower level value; a level slope trim is normally done at or near the
upper level limit.
The level trim process corrects for offset and/or slope errors by
adjusting the controller height and process density terms.
For best results, perform a level offset trim before performing a level
slope trim.
Best overall accuracy is also achieved by performing the offset and
slope trim at two widely separated level values.
NOTE
Changing certain level values (controller height or process density)
after performing a level trim overwrites the results of the level trim.
Trim Level
To perform a level offset trim, first adjust the level to the value you
wish to trim at. Once the process stabilizes, perform an offset trim. You
will be asked to select the level engineering units and then enter the
level value observed with a sight glass or other visual reference.
Once the level offset trim is complete, you may notice that the
controller height in the level setup parameters has changed. This is
how the level offset trim is accomplished.
To perform a level slope trim, first adjust the level to the value you wish
to trim at. Once the process stabilizes, perform a slope trim. You will be
asked to select the level engineering units and then enter the level
value observed with a sight glass or other visual reference.
Once the level slope trim is complete, you may notice that the controller
height and process density in the level setup parameters have changed.
This is how the level slope trim is accomplished.
Level Trim Recall
The level offset and slope trims modify the user-entered values for
controller height and process density. If the trims are not performed
satisfactorily, the user may revert to the controller height and process
density parameters entered during initial device setup by performing a
level trim recall.
HART Comm.
6, 1, 1, 6, 2
HART Comm.
6, 1, 1, 6, 3
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