Garmin G3X Touch Installation Manual page 760

34.4.26.4 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)
• Custom Sensor
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. Refer to pin description in Section 25 for supported digital signal characteristics.
NOTE
The Sandia ST26 tach converter is required to support turbine engine RPM.
FADEC: The GEA 24 can be configured to monitor RPM data from the following FADEC interfaces:
• Rotax (912iS/915iS)
• Lycoming (iE2)
• ULPower
34.4.26.5 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 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.
For turbine engines, select one of the "Custom" configurations to display a second RPM gauge. Refer to
pin description in Section 25 for supported digital signal characteristics.
NOTE
The Sandia ST26 tach converter is required to support turbine engine RPM.
.
190-01115-01 G3X/G3X Touch Install Manual - GDU 4XX Config and Post Install Checkout
Rev. AC
Figure 31.3).
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