Smoothing And Time-Delays; Fuel/Load Switching - ABB Uvisor SF910i User Manual

C Flame Detection Theory
C.3 Smoothing and Time-Delays
Figure C.2: Flicker-Frequency Trip Points
When the High-Limit feature is enabled, the SF910i will vote a Flame-Off condition
whenever one or more of the active parameters are above the programmed High-Limit
values.
The default condition for the High-Limit feature is OFF, so that the user must enable this
Flame-Logic.
C.3

Smoothing and Time-Delays

Since rapid changes can occur in any combustion system, special features are included
to minimize the chance of false readings due to transient conditions. Smoothing filters
(rolling averages) can be applied to the Measured-Values to reduce the impact of sudden
changes.
C.4

Fuel/Load Switching

In some combustion firing systems, the flame characteristics may change with fuel or
load changes. Under these circumstances, the ideal trip, sensitivity, and Time-Delay
settings may be different for the different fuels or load.
Use the Fuel/Load Switching feature through serial line to more precisely determine the
flame characteristics under these conditions.
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