Garmin G3X Installation Manual page 734

RPM
The following sensors can be configured for the RPM 1 input on the GEA 24, or the RPM input on the
GSU 73:
• Electronic Ignition Tachometer Signal (1, 2, 3, or 4 pulses per revolution - Lycoming and
Continental electronic ignitions typically output 2 pulses/revolution for 4-cylinder engines and 3
pulses/revolution for 6-cylinder engines)
• Jabiru Alternator RPM (6 pulses per revolution)
• JPI 4208XX - Magneto Port RPM Sender (4- or 6- cylinder)
• Rotax Trigger Coil RPM
• UMA 1A3C Mechanical RPM Sender
• UMA T1A9 Magneto Port RPM Sender (4- or 6-cylinder)
Rotax 912iS: For the GEA 24, select "Rotax FADEC" as the RPM configuration to use engine speed data
from the Rotax 912iS FADEC interface.
NOTE
External components are required when using the Rotax Trigger Coil configuration with
the GSU 73 (see
Custom: These options allows the installer to enter up to 8 points of frequency-to-RPM calibration, using
any RPM sensor that has a known frequency output. The custom RPM configurations accept frequency
values up to either 500 Hz or 1 kHz; the lower-frequency configuration is better suited to noisy RPM
signals. Custom RPM configurations also support engine speed readouts that display in percent instead of
RPM.
RPM 2
A second RPM input is provided (RPM 2 input on the GEA 24, CAP FUEL 1 / RPM 2 on the GSU 73).
For turbine engines, select one of the "Custom" configurations to display a second RPM gauge. These
options allows the installer to enter up to 8 points of frequency-to-RPM calibration, using any RPM sensor
that has a known frequency output. The custom RPM configurations accept frequency values up to either
500 Hz or 1 kHz; the lower-frequency configuration is better suited to noisy RPM signals. Custom RPM
configurations also support engine speed readouts that display in percent instead of RPM.
For piston engines, a second RPM input from an electronic ignition system can be configured. If both RPM
inputs are configured, the highest of the two valid RPM values will be displayed. This configuration is
useful for aircraft equipped with dual electronic ignitions, where the tach signal ceases to function during a
pre-takeoff ignition check
NOTE
The Sandia ST26 tach converter is required to support turbine engine RPM.
.
GP (General Purpose) 1-7
Custom Analog: These inputs allow the monitoring of inputs such as O2 sensors, timing advance, etc., and
allows the installer to create/enter the name of the gauge. This option allows the installer to enter up to 8
points of voltage-to-numeric value calibration.
Misc (Miscellaneous) Pressure
These inputs (GEA 24, J244, Pin 31; GSU 73, J732, Pin 31) allow the monitoring of inputs such as
hydraulic pressure, and allow the installer to create/enter the name of the gauge. Options of several
different Kavlico pressure sensors are provided, or if "Misc Press (Custom)" is selected, the installer can
enter up to 8 points of voltage-to-pressure calibration.
190-01115-01 G3X/G3X Touch Install Manual - GDU 45X/46X Config and Post Install Checkout
Rev. AA
Figure 29.3).
Page 32-139