ABB Uvisor SF910i User Manual page 144

C Flame Detection Theory
C.2 Measured-Values
– Flame Temperature
These values are compared to Pull-In and Drop-Out limits that the user set during the
tuning process.
If Measured-Values exceed the programmed Pull-In limits, the SF910i will:
– Vote a Flame-On condition in the program Flame-Logic.
– Energize the Flame-relay.
– Provide a Flame-Proven signal on the redundant serial ports.
If Measured-Values fall below the programmed Drop-Out limits, the SF910i will:
– Vote a Flame-Off condition in the Flame-Logic.
– De-energize the Flame-relay.
– Provide a Flame-Off signal on the redundant serial ports.
Figure C.2
Measured-Values are Application Dependent
Depending on the application (flame, burner, and fuel) and/or the spectral range (IR,
UV, IR+UV, and so on), certain Measured-Values may be low in strength or may vary
greatly with the operation of the burner.
Under that conditions, these Measured-Values are not reliable for flame detection and
may be removed from the Flame-Logic.
Flame Detection using High-Limits
In rare instances, more robust operation can be achieved by also applying a High-Limit
to Measured-Values.
8VZZ005286 B
shows an example of the Pull-In and Drop-Out settings for Flicker-Frequency.
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