Haltech E6A - Manual (Page 115)

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When ferrous metal i.e. metal that a magnet will attract, is passed very close to the pole piece,
the pickup will generate a voltage similar to figure E.5a on the positive wire. The amplitude of
the signal will vary with the speed at which the ferrous metal passes the pole piece. At low
speeds the signal may only be several hundred millivolts, but at high speeds it could rise to 20
volts or more. The sudden drop in the signal from positive to negative seen in figure E.5a
corresponds to the metal being directly in line with the sensor. As can be seen, the signal is not
the square wave signal that is requires by the E6A, plus at low speeds the signal is too low.
This is why the RA3 is used.
The voltage input of the reluctor adapter must first go to a positive peak, which arms the
circuit in the RA3. When the signal rises to approximately 70 - 80% of the peak value the RA3
will generate a falling edge, and when the signal crosses zero volts the RA3 will generate a
rising edge which is used the trigger the Haltech ECU. If the wires are reversed and the signal
goes negative first, the RA3 will generate a pulse but it will NOT trigger the E6A correctly and
some strange things can happen to the ignition timing. For instance, the timing may retard as
revs increase or multiple triggers can be generated. Incorrect wiring of a reluctor trigger can
cause major problems. If you are using a reluctor pickup ensure that they are wired with the
correct polarity.
NOTE: In the IGNITION SETUP page Trigger Edge should be set to RISING.
+ V
ZERO
(GND)
- V TRIGGER POINT IS RISING EDGE
ZERO VOLT CROSSING
OUTPUT
OF RA3
Figure E.5. Top diagram is the signal from the magnetic reluctor sensor. Bottom diagram is
the signal after modification by the RA3.
A variation on this type of pickup uses a magnet moving past the pole piece, instead of ferrous
metal, but generating the same wave form. An example of this type is the MSD flying magnet
crank trigger. This pickup can be used with the RA3 reluctor adapter to trigger the E6A ECU.