---------------------------------------------------------- Avionics-List Digest Archive --- Total Messages Posted Thu 04/08/04: 1 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 11:06 PM - EFIS 1 and SL-30 (Dean Psiropoulos) ________________________________ Message 1 _____________________________________ Time: 11:06:35 PM PST US From: "Dean Psiropoulos" Subject: Avionics-List: EFIS 1 and SL-30 --> Avionics-List message posted by: "Dean Psiropoulos" Years ago: Actually not as long ago as one might think, aircraft instruments were electro-mechanical devices (as opposed to TV screens). These electro-mechanical instruments were driven by analog electronics (instead of digital computers) and those interfaces were mainly resolver and synchro (as opposed to RS232 and USB). Resolvers are rotational sensors that are driven by the little knobs on aircraft mechanical instruments (ie. Omnibearing selector on the VOR head). Synchros are the little "motors" inside aircraft mechanical instruments that drive airspeed and altimeter (on old Boeing 727s for example). These little critters are something akin to stepper motors that are used in computer printers today. They are 3 phase devices that can be driven to a precise position to facilitate accurate pointing of the hands on an airspeed indicator (on large commercial aircraft, our mechanical airspeed indicators are of course driven by the pitot static system) or.....sense the positioning of a knob when someone inputs data into a 727's autopilot for example. Resolver and synchro use is much more prevalent on large commercial aircraft however it does filter down into the GA arena (quite a bit on biz jets, very little on piston singles). Bottom line for your EFIS dilemma is that you will NOT be able to use a conventional electromechanical VOR/ILS indicator with the SL-30 set to the serial mode. You'll need a VOR/ILS indicator that outputs/accepts serial data in the format that the SL-30 uses it. It may be possible that you can rig up some kind of relay where you can flip a switch and transfer the signal to an electromechanical VOR/ILS indicator if the EFIS dies but I haven't looked into this. And since I bought the Dynon instead of the Blue Mountain, I won't be needing to solve this problem for my airplane (I also won't have the cool HSI you all have either). Let us know what you finally do to solve this one. Thanks. Dean Psiropoulos RV-6A, 24907 Canopy is finally on!!!!