Haltech E8 - Manual (Page 153)

Haltech E11/E8 Instruction Manual
• Rising Edge Triggered – Some Honda and CDI style ignition modules are known to be rising
edge triggered. These modules expect a 12V input signal when idle. When the voltage falls to 0V,
the module charges the coil. When the voltage returns to 12V, the spark is fired.
The Coil Negative Signal
The coil’s charge time can be determined from the coil -ve signal. When the coil switches on, voltage at
the coil negative terminal drops to zero. As the coil charges, the voltage rises slightly, until a sharp rise
where the ignitor current limits. Leaving the coil switched on any longer will not increase the energy in the
coil or of the spark. See figure D7.
When the ignition firing frequency is high, there will not be enough time to charge the coil completely.
After firing the spark, the ECU will wait for a short period, and then switch the coil on again, regaining
much of the lost energy in “ringing”. This break time should normally be 0.7 to 1.5ms.
Figure D7. Illustrates Charge Time & Break Time
Note: For safety and reliability, always use igniters that are internally current limited.
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GND
+12V
4ms Charge
time
Time
Voltage
Spark Edge