Maintenance - Siemens SITRANS Probe LU Quick Start Manual

8. Enable False Echo Suppression: set P837 (Auto False Echo Suppression)
Off
0
Use "learned" TVT
Value 1 *
"Learn"
2
Using P837 and P838 (perform this function at low tank levels)
The TVT (Time Varying Threshold) curve sets a threshold which screens out false echoes
SITRANS Probe LU displays an incorrect full level, or if the reading fluctuates between a false
high level and a correct level, use P838 and P837 together to elevate the TVT (Time Varying
Threshold) in this region and de-sensitize the receiver from any 'base noise' caused by internal
transducer reflections, nozzle echoes, or other vessel false echoes
Using P837 and P838 (continued)
.
Notes:
• Use this function only if there is a minimum distance of 2 meters from SITRANS Probe LU
to the material. This function works best if the vessel is empty or nearly empty.
• Set P837 and P838 during start up, if possible.
• If the vessel contains an agitator, the agitator should be running.
a. Determine the actual distance from the transducer face to the material level.
b. Select P838 and key in [distance to material level – 0.5 m].
c. Select P837, then press 2 (Learn) and ENTER
Learned TVT) after a few seconds.
9. Return to RUN
Press PROGRAM
SITRANS Probe LU Communications: HART
mA Output with Level, Space, and Distance operation
See
Note:
illustration of the mA output with different modes of operation.
• You will need the full manual to acquire the list of applicable parameters.
• Please contact your local representative concerning the availability of the HART DD for
SITRANS Probe LU.
• We recommend that you use SIMATIC Process Device Manager (PDM) to program your
instrument.

Maintenance

SITRANS Probe LU requires no maintenance or cleaning.
Unit Repair and Excluded Liability
For detailed information, please see the inside back cover.
1.
False echoes can be caused by obstructions in the beam path.
2.
For more details on Auto False Echo Suppression, please see the full manual.
Page EN-14 SITRANS Probe LU (HART) – QUICK START MANUAL
to return to RUN mode: setup is complete.
2
.
. P837 will automatically revert to 1 (use
on page 12 for an
1
. If
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