Loe (Loss Of Echo) Timer; Fail-Safe Mode; Fail-Safe Value - Siemens sitrans LR200 Instruction Manual

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 and
mA output 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.
Options

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 (2.4.2.) to Use substitute value.
• Go to Fail-safe Value FB1 (2.4.3.) and enter the desired value.
7ML19985JR01 SITRANS LR200 (PROFIBUS PA) – INSTRUCTION MANUAL
Material level to be reported
Substitute value (Default value used as output value).
* Last value (Store last valid output value).
Use bad value (Calculated output value is incorrect).
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