Set The Device To Ignore The False Echo; Wrong Reading - Siemens SITRANS LR500 Series Operating Instructions Manual

11.6.2.3

Set the device to ignore the false echo

To adjust the time-varying threshold (TVT) to ignore the false echoes, use auto false echo
suppression. If this does not correct the problem, enable custom TVT shaper mode and manually
shape around false echoes. For more information, see:
• Near range (Page 133)
• AFES wizard (Page 82)
• Custom TVT shaper (Page 136)
11.6.3

Wrong reading

If the reading is erratic or jumps to some incorrect value periodically, ensure:
• Surface monitored is not beyond the transmitter's programmed range or the transmitter's
maximum range
• Material is not falling into the transmitter's acoustic beam
• Material is not inside the blanking distance (parameter "Near range") of the transmitter.
• Algorithm is set incorrectly
Adjust the echo algorithm
Use SIMATIC PDM to view echo profiles and to make adjustments to parameter Algorithm
(3.3.3.1) (Page 133).
If multiple echoes appear on the echo profile, typical of a flat material profile (especially if
the vessel top is domed), use the "True first echo" algorithm. Also, if the true echo has jagged
peaks, use parameter "Reform echo".
Should a stable measurement still not be attainable, contact Siemens representative.
SITRANS LR500 series with mA/HART
Operating Instructions, 03/2024, A5E51099898-AA
Diagnostics and troubleshooting
11.6 Operation troubleshooting
167