Loss Of Echo (Loe) - Siemens SITRANS LR260 Operating Instructions Manual

Damping example
①
②
③
④
● time constant = 2 seconds
● input (level) change = 2 m
● In 5 time constants the output rises exponentially: from 63.2% of the change in the first time
constant, to almost 100% of the change by the end of the 5th time constant.
A.8

Loss of Echo (LOE)

A loss of echo (LOE) occurs when the calculated measurement is judged to be unreliable
because the echo confidence value has dropped below the echo confidence threshold.
If the LOE condition persists beyond the time limit set in 2.4.1. LOE Timer the LCD displays the
Maintenance Alarm icon, and the text region displays the fault code S: 0 and the text LOE.
If two faults are present at the same time, the fault code, error text, and error icon for each fault
are displayed alternately. For example, Loss of Echo and Temperature Sensor Failure.
SITRANS LR260 with mA/HART
Operating Instructions, 11/2019, A5E32337683-AD
Level (m)
Time (s)
Input (level)
Smoothed output
S: 0 LOE
S: 11 Temp. Sensor Failure
Appendix A: Technical reference
A.8 Loss of Echo (LOE)
157