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chuckwn2
11-05-2010, 05:33 PM
Is it possible to share the output of one AFS OAT probe with two AFS EFIS's? My apologies if this question has been answered here before.

I realize that the probe will be powered by only one EFIS. I also promise to ground both EFIS's to a common ground point via the case grounds and the power grounds.

Thanks,

Chuck

Trevor Conroy
11-08-2010, 11:56 AM
Hi Chuck,

Yes you can share the OAT between screens, but not if both screens have air data input. If both screens have air data input, each needs its own OAT probe. What types of units do you have? EE, EFIS, EM, MFD??

chuckwn2
11-09-2010, 06:03 PM
Trevor,

I am planning installation of a second screen. Both screens will have air data input. I would like to share the output of one OAT probe with both screens.

It is my understanding that the output of the probe is a voltage that varies from roughly 0 to 5 Volts depending on temperature. I am curious why two EFIS units could not be connected to the output of one OAT probe. I realize that only one EFIS will power the probe.

Thanks,

Chuck

Trevor Conroy
11-10-2010, 09:10 AM
Chuck, if both screens have air data input, they will need their own OAT probe. It uses microamps/degree(K), which is current rather than voltage so you would be splitting the current in half if you connected it to two screens thereby leading to an inaccurate temperature reading.