ABB Uvisor SF910i User Manual page 87

11 Configuration Parameters in Flame Explorer
Quality Normalization Parameters
Frequency Sensitivity
Frequency sensitivity impacts the Flicker-Frequency measurement. The higher the
frequency sensitivity setting, the lower the measured Flicker-Frequency.
Frequency sensitivity is adjustable in increments of 1, between a low of 5 for IR sensor
or 10 for UV sensor and a maximum of 100. The highest Flicker-Frequency will be
measured at a setting of 5 and the lowest Flicker-Frequency at a setting of 100.
Accounting for Background Light
In some applications, the change in Flicker-Frequency resulting from a change in
frequency sensitivity may be different for light in the background when compared to the
burner flame.
In these cases, the frequency sensitivity function can be used to maximize the difference
between burner ON and burner OFF (background) Flicker-Frequencies.
SF910i is then able to discriminate between the burner flame and background light.
On some occurrence, the background light might be too high, resulting in both, input
signal saturation (alarmed by Error 35) and reduced capability to detect frequency leading
to poor discrimination. This situation can be improved by interposing an orifice between
the flame and the lens. The orifice is secured within the thermal isolation union with a
retainer (See appendix section).
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