Siemens SITRANS LR580 User Manual

11.6.2 Measurement di󹪟culties
If
the value in parameter "Fail-safe LOE timer" expires due to a measurement di󹪟culty, the value
set in parameter "Fail-safe loss of echo" displays. In rare cases, the SITRANS LR500 series may lock
on to a false echo and report a 󹪝xed or wrong reading.
Loss of echo (LOE)
The value set in parameter "Fail-safe loss of echo" displays when the echo con󹪝dence is
below the threshold value set in parameter "Echo threshold".
LOE occurs when:
• The echo is lost and no echo is shown above the ambient noise (resulting in low values for
parameters "Con󹪝dence". For example, foaming liquids or antenna buildup are the most
common cause for lost echo.
• Two echoes are too similar to di󹪜erentiate (when BLF algorithm used) (resulting in low
con󹪝dence and low echo signal strength)
• No echo can be detected within the programmed range (parameter "Far Range" can be used
to extend range).
If value set in parameter "Fail-safe loss of echo" displays, check if the surface monitored is
within the transmitter maximum range.
11.6.2.1 Adjusting aiming
For optimum performance on solid materials, adjust aiming to provide the best con󹪝dence and
echo strength for all material levels within the measurement range.
Displaying echoes
To check echo pro󹪝les, use HMI, diagnostics, and view echo pro󹪝le and an engineering
system such as SIMATIC PDM. For instructions on how to display an echo pro󹪝le, see section
SIMATIC PDM (Page207), and for details on how to interpret an echo pro󹪝le, see section Echo
processing (Page201).
Increase fail-safe timer value
Increase the value in parameter "Fail-safe LOE timer" only if the fail-safe operation will not be
compromised by the larger value.
Try this only if LOE exists for short periods of time.
11.6.2.2 Fixed reading
If the reading is a 󹪝xed value, regardless of the material surface distance, ensure:
• Beam is free from obstruction
• Properly aimed
• Material mixer (if used) is operating while the device is operating. If it is stopped, ensure that
the mixer blade has not stopped directly below the transmitter.
Diagnostics and troubleshooting
11.6Operation troubleshooting
SITRANS LR500 series with mA/HART
166 Operating Instructions, 03/2024, A5E51099898-AA

Siemens SITRANS LR580 Specifications

General

Brand	Siemens
Model	SITRANS LR580
Category	Transmitter
Language	English