ABB Uvisor SF910i User Manual page 89

11 Configuration Parameters in Flame Explorer
Delay Drop-Out
Delay Drop-Out function is a "Time-Delay on Drop-Out" feature for flame detection. If a
Flame-Proven condition exists, and one or more of the Measured-Values are below or
above the Trip Points, this function will provide a delay before:
– Voting a Flame-Off condition
– De-energizing Flame-relay(s)
This feature allows the Flame Scanner to ride through transient events. The user can
set the amount of Time-Delay from 0.2 to 4.0 seconds. This parameter is also related
with known FFRT (Flame Failure Response Time).
For safety reasons, the user is requested to prove the Flame Failure Response
Time (FFRT) of the SF910i under any burner load/fuel conditions and under any
selected file of parameters. For EN298 application, the user needs to set the DELAY
DROPOUT parameter to <= 0.9s to fulfill the requirement of EN 298 that the FFRT
shall not exceed one second. If there are further adjustments of the flame detector
(DELAY DROPOUT), do not cause the time to rise above one second.
Delay Pull-In
Delay Pull-In function is a "Time-Delay on Pull-In" feature for flame detection. If a proven
Flame-Off condition exists, and one or more of the active Measured-Values exceed the
programmed Pull-In values, the SF910i will delay before:
– Providing a Flame-On signal
– Energizing the Flame-relay(s)
The user can set the amount of time for the delay, and this only allows enough time to
ensure that the fuel-supply-valves clear the fully-opened limits before the SF910i proves
flame.
This feature allows the Flame Scanner to ride through transient events. The user can
set the amount of Time-Delay from 0.1 to 10.0 seconds.
Quality Threshold
Quality Threshold allows the user to specify a threshold on quality level. If the Safe-relay
usage is configured as "Quality-relay", the Safe-relay will be energized if the calculated
quality is equal or above the configured threshold and will be de-energized if the calculated
quality is below the configured threshold.
If the Safe-relay is not used as Quality-relay, this parameter has no effect.
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