Spent the day experimenting with interfacing the FT-60 fuel flow transducer to both the Trio GX Pro Autopilot and the Garmin G3X. Trio was concerned that the internal pull up resistors of both devices in parallel would create an issue with the FT-60. Electronics International didnt think there would be an issue.
I connected a pump to the right fuel tank line of the fuselage, and submerged an intake line into 5 gallons of aviation fuel then disconnected the fuel line from the fuel servo and then connected a return line back to the container with the aviation fuel. This set up allowed me to test the entire fuel system including fuel pressure and fuel flow and verify that there were no leaks.
I first created a baseline measurement by just having the Garmin G3X connected to the FT-60 fuel flow transducer. The fuel flow indicated 43.6 GPH. Then I disconnected the Garmin system and connected the Trio to the FT-60 the flow indicated 39.8 GPH. The difference is just in how the flow is calculated from the K factor of the FT-60. Both instruments allow the user to adjust the K factor based on system installation so the difference is of no concern to me.
I then connected both instruments in parallel to the FT-60 and verified the same numbers from both.
Everything looks great. I will need to change the wiring, currently the power for the FT-60 comes from the Garmin G3X engine module. If this were to fail then I may loose the 12 volts needed to power the transducer. Ill move the transducer to the avionics subsystems fusepanel with a one amp fuse.
