Emerson Rosemount 3101, Reference Manual

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Reference Manual
00809-0100-4840, Rev CB
Section 4: Starting up
February 2015
Starting up
6. Press the red button

to save if the new 20 mA level is correct, or press the blue
button

to not save. Afterwards, depending on the button pressed, either the “S-20”
menu or the next menu appears.
4.3.8 Learn about echoes from false targets (on the 3101)
The Rosemount 3101 has an easy-to-use “Lrn” (Learn) routine that allows the instrument to
learn up to two false echoes, which can then be ignored in future operations.
If the application is simple and there are no false echoes, press the green button

to exit the
integral display menu and return the instrument to indicating the level reading on the display.
If an echo other than the true liquid surface echo is detected and an incorrect level reading is
indicated, the instrument can learn to ignore this false echo. The “Lrn” routine may be used at
any time, either during or after setting-up or if a problem occurs later.
Note
See Figure C-1 on page 102 for a map of the programming menu structure and how to access all
the menu options.
To store a false target echo
1. If entering the menu system from the PV display, press the green button

repeatedly
until the “Lrn” menu option is indicated (see the above note).
2. Press the blue button

to enter the “Lrn” menu. The display indicates “LrnX” where
“X” (0, 1, or 2) is the number of stored false target echoes.
3. To exit to the menu at this stage, press the red button

and then the green button

to
get to the next menu option. Otherwise, continue with step ( 4 ).
4. To store a new false echo, hold the blue button down

for five seconds.
5. The display alternately flashes “Lrn” and the false target position. After four seconds,
the false target position is stored and the display re-indicates “LrnX” alternating with
the distance for the stored false echo.
6. Press the red button

to save this false echo, or press the blue button

to not save.
7. To store another false target echo, repeat from step ( 2 ). Otherwise, press the green
button

to exit the menu system and return to the PV display.
Note
If there are two false echoes stored (“Lrn2”), the transmitter will not allow another echo to be
stored until the memory is cleared (see the next procedure).
When a false echo is stored, the transmitter sets up a 'window' around the false target and
ignores any echo from that window, unless the echo received from the liquid surface is larger
than the stored false echo. There may be no change in the transmitter output current while the
liquid level moves through this window, which is equivalent to a distance of 8 in. (20 cm).