How does the
photoeye calculate the phase angle ?
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The 1x rpm trigger provides the box
with the period of the frequency being measured - the period of
1 cycle at 1x rpm.
-
The box takes that period (measured
in seconds) and divides it by 360.
-
Once all the math is completed, the
box is ready. When instructed to collect a phase angle, it waits for the
trigger mark to pass so it can begin a count up to 360.
-
After beginning it's count, it awaits
the arrival of a peak signal from the transducer. The moment it has that,
it stops the count. That is the phase angle.
-
For the sake of accuracy, several angles
are checked and an average is what is eventually displayed as the
phase angle.
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