August 2020
Reference Manual
L231040 Rev AD
15
Deadzone:
This menu is mainly utilized at the factory to achieve
optimal linearity near the deadband close to the electronics.
This feature was released just in case in-field adjustments
are necessary.
1-point Calibration Procedure (1pt Cal):
The following menu is the 1 –point Calibration procedure.
This procedure was designed to help the user get up and
running in an emergency. If electronics have to be shared in
an emergency the following procedure guides the user
through a “quick” calibration procedure that does not
require level simulation but instead works with the current
level (1 point) in the vessel/tank.
1. Enter into the “1pt Cal” menu by changing the “no” to a
“yes” and pressing enter.
2. The first menu is “SelLngth” or select length. This is not
the measuring range but the overall probe length. This
information can be found on the label of the instrument
housing. (See Section 2.1 Product Identification). Enter the
value in using the up or down arrows and press enter.
3. The second menu is “Sel LRV” or select lower range value.
Most of the time this value is at 0.00in. It is recommended
to leave this value at zero and press enter.
4. The next menu is “Sel URV” or select upper range value.
Enter in the desired measuring range and press enter.
5. The “Energy” menu is next. This parameter controls the
amount of energy being sent down the sensor probe.
Longer sensor probes require more energy shorter sensor
probes require less energy. Please contact the factory for
guidance with this parameter.
6. The “DCOffset” menu is the DC voltage that the signal is
offset by. It is useful for eliminating some noise. Please
contact the factory for guidance with this parameter.
7. The “HoldTime” menu is the amount of time the energy
being sent down the probe is sustained. Note: a longer
hold time can increase the deadband near the electronics.
Please contact the factory for guidance with this parameter.
8. The last menu is the “CrntLvl” or current level menu. Enter
the known current level in the vessel/tank (in engineering
units) and press enter. The calibration should take place and
the transmitter should be operational. If the next menu
appears then the operation was successful. If the menu
reverts back to the beginning of the “1pt Cal” menu then
the operation was unsuccessful. Further troubleshooting
may be necessary if the operation is unsuccessful. See
Section 6 for troubleshooting guide.
Level Adjustment (LvlAdjst):
If the level gage indicator and level transmitter reading do
not match or appear to be incorrect by a few inches then
the “LvlAdjst” function can be utilized. Enter into the menu
and simply use the up and down push buttons to enter the
current level being displayed by the level gages visual
indicator and then press enter. The transmitter will adjust
the calibration and output accordingly. Note: Be careful
make sure this is what is desired.
Field Reversible Transmitter (FlipPrb):
An important and key feature of the LTM-350 Model is the
ability to flip (rotate) the entire transmitter 180 degrees.
This procedure is only for MLI mount transmitters with an
elbow connection on them. If the transmitter does not have
an elbow connection please contact factory for assistance. If
the need arises and a bottom mount transmitter is preferred
over a top mount transmitter or vice versa then following
these simple steps. THIS PROCEDURE IS FOR MLI MOUNT
TRANSMITTERS ONLY.
1.
Physically flip (rotate) the entire transmitter (this
includes the sensor probe) and mount it
accordingly.
2.
Remove the front glass cover of the transmitter
enclosure and then using needle nose pliers pull on
This option/feature only appears in software revisions
1.01.15 or higher.
Please consult factory before attempting this procedure.
Document transmitter’s serial number for better assistance.
The 1-point calibration may not be within the published
accuracy specification. Again this procedure was designed
to get a critical application up and running. A recalibration
(two point calibration) may be highly desirable as soon as
the opportunity presents itself.
Be careful not to damage the sensor probe while
rotating the transmitter.
