User's Manual

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A5E32337685 SITRANS LR260 (PROFIBUS PA) – OPERATING INSTRUCTIONS Page 107
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D: Technical Reference
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.
S: 0 LOE S: 11 Temp. Sensor Failure
LOE (Loss of Echo) Timer
LOE Timer determines the time to elapse after the last valid reading before a Fail-safe
state is activated. Fail-safe Material Level determines the level to be 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
return to the current level.
Fail-safe Mode
The purpose of the Fail-safe setting is to put the process into a safe mode of operation in
the event of a fault or failure. The value to be reported in the event of a fault is selected so
that a loss of power or loss of signal triggers the same response as an unsafe level.
Fail-safe mode may be triggered by a loss of echo, a bad configuration, or certain device
faults. You can select on of three possible values to be reported when a Fail-safe mode is
activated.
Fail-safe value
When the LOE Timer (2.4.1.) expires, the material level to be reported is determined by
Fail-safe Mode. If the option Use substitute value is selected, a user-defined value can be
reported.
The two Analog Input Function blocks are set separately. For example, to set a user-
defined value for AIFB1:
•Set Fail-safe Mode FB1 (FS MODE FB1) (2.4.2.) to Use substitute value.
•Go to Fail-safe Value FB1 (FS VALUE FB1) (2.4.3.) and enter the desired value.
Material level to be reported
Options
Substitute value (Default value used as output value).
* Last value (Store last valid output value).
Use bad value (Calculated output value is incorrect).