Haltech E6M - Manual (Page 146)

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E.5 Ignition Output
The E6H/E6M ECU has one dedicated ignition output, but the two Digital Outputs can also
be used for ignition outputs to allow for some Direct Fire applications (See Appendix B).
Twin spark engines that fire two spark plugs within one cylinder simultaneously (with two
coils, twin distributors and two spark plugs per cylinder) need only one output channel but
two igniters (one for each coil) both connected to the same ignition output.
The ignition signals on the E6H/E6M are generated by the same type of drivers as the
injectors ie. the output pulls to ground when it is switched on. These output signals cannot
be used in any circumstances to drive an ignition coil directly: they must drive some
form of igniter. An igniter is a device which is capable of sinking the large currents required
to charge the coil. The Haltech igniter module part number EB023 is available as an optional
extra. These “intelligent” igniter modules perform current limiting and dwell control on their
own. The back of the igniter can become extremely hot. Refer to Chapter 1 for details on
mounting.
The Regitar equivalent part, 1G-H004, has been tested and found NOT to work satisfactorily
with the E6H/E6M ECU. Please do not use it.
So called “dumb” igniters (i.e. having no dwell control) are also available from Haltech.
Standard igniters already installed on engines are often dumb igniters and the E6H/E6M can
control a wide range of such igniters. Set the “Output Type” to “Constant Charge” in the
ignition set-up page for dumb igniters.
Tailoring the Ignition Output Signal
The E6H/E6M has the flexibility to tailor the ignition output signals to suit different ignition
systems. The parameters that may be adjusted can be found in the Ignition Set-up, area (see
sec.4.6.1). The default setting for the ignition output, selected to suit the supplied Bosch
igniter, is a 70/30 constant duty cycle signal firing on the falling edge.
The E6H/E6M is suited to both intelligent igniter modules that perform their own dwell
control (use constant duty output) as well as “dumb” igniter modules that require dwell
control (use constant charge output)
The duty cycle of a square wave is the ratio of its high time to its period. E.g. a 70/30 duty
cycle signal is high for 70% of its period and low for the remaining 30% regardless of
frequency, as shown in figure E7. Constant duty can also be used on aftermarket capacitive-,
inductive- or multiple-spark discharge systems such as MSD or Jacobs.