RDAC X installation manual (800 KBytes) - MGL Avionics

Connecting the rev counter
REV counter
wire from
ignition system
After you have connected the rev
counter terminal to the signal source you
need to set the number of pulses per 10
revolutions in the Calibration Menu.
The calibration itself depends on your
engine type and what kind of signal you
are using. Typical sources are:
Magneto coils (suitable signal at the kill
Ballast resistor link
switch).
Primary (low voltage) side of ignition coil, at contact breaker or electronic
ignition module.
RPM counter output of electronic ignition systems (for example Bosh
Motronic).
RPM pickup devices such as hall-effect sensors on flywheels etc.
Typical calibration settings are 10 or 20 for most engines. Other pulse counts
per 10 revolutions are also possible for some engines.
Note: The RDAC X EMS contains a 220 ohm ballast resistor that is in circuit if
the indicated link is closed. Normally you would not need this. We have found
a few Rotax engines that create a very noisy signal where you will need to
use it. The problem manifests itself by several rev band regions giving
unstable rev readings. Should you be unlucky enough to have one of these
systems, please close the link with the supplied connector or solder the link
closed.