E.3 trigger edge – Haltech E6X Manual Win Version User Manual

Page 136

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E6X Manual

136

E.3 Trigger Edge


Trigger Edge

The ECU uses the signal transitions from low to high called rising edges and high to low
called falling edges to determine engine position, these transitions occur at specific angles
across the rotation of the crank (half cycle) or cam (full cycle). In most instances the ECU
will only uses one type of transition (rising or falling) for a trigger and this is known as the
Trigger Edge.



In the example shown below the trigger occurs on a rising edge at 70° BTDC. The second
edge, a falling edge, could occur any time after the rising edge, in some installations the
second transition will coincide with 10° BTDC or TDC. This second edge will have no effect
on the operation of the ECU. It is only the position of the triggering edge that is of
importance. Example 2(b) shows the same trigger angle but with the opposite trigger edge.





Falling Edge

Rising Edge

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