Echo Lock; Loss Of Echo (Loe); Fail-Safe Mode; Fail-Safe Timers - Siemens SITRANS LR250 Instruction Manual

Echo Lock

When the echoes are received, the relevant echo algorithm is applied to determine the
true material echo. If the selected echo is within the window, the window is then
centered about the echo. Otherwise the window widens with each successive shot until
the selected echo is within the window, which then returns to its normal width.
Echo Lock selects the measurement verification process:
Values
• When Echo Lock is Off, SITRANS LR 250 responds immediately to a new
measurement (within the restrictions set by the Maximum Fill / Empty Rate).
However, measurement reliability is affected.
• When Maximum Verification or Material Agitator is selected, a new measurement
outside the Echo Lock Window must meet the sampling criteria.
• When Total Lock is selected, Echo Lock Window is pre-set to 0, and the window is
automatically calculated after each measurement.

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
displays the Service Required icon, a wrench accompanied by three dots
text region displays the fault code S: 0 and the text LOE.

Fail-safe Mode

Fail-safe Timers

2.4.1. Failsafe Timers
Fail-safe state is activated.
reported when the Fail-safe timer expires. Upon receiving a reliable echo, the loss of
echo condition is aborted, the Service Required icon and error message are cleared, and
the reading and mA output return to the current level.

Fail-safe value

2.4.1. Failsafe Timers
When the
2.4.2. Failsafe Material Level
Fail-safe Material Level
HI
LO
HOLD
VALUE
7ML19985JE01
0
Off
1
Maximum Verification
2 *
Material Agitator
3
Total Lock
determines the time to elapse after the last valid reading before a
2.4.2. Failsafe Material Level
expires, the material level to be reported is determined by
.
Use Maximum mA Limit as material level
Use Minimum mA Limit as material level
Level remains at last reading
User-selected value
SITRANS LR250 (HART) – INSTRUCTION MANUAL
2.4.1. Failsafe Timers
the LCD
determines the level to be
and the
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