---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Sun 07/26/15: 1 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 12:13 PM - ARINC 429 wiring practices (Charlie England) ________________________________ Message 1 _____________________________________ Time: 12:13:19 PM PST US Subject: AeroElectric-List: ARINC 429 wiring practices From: Charlie England I'm in the process of wiring my panel, which includes an old Garmin 430 (non-WAAS), an AFS AF4500S EFIS, AFS ARINC module, and AFS Pilot autopilot. I'm using the AF3000-4000 Installation Guide, v7.4. Looking through the AFS docs, their wiring diagrams are a bit...inconsistent... on how to treat the ARINC and serial port data wiring. So I did some digging in the InterWebs to find the 'proper' way to wire ARINC 429 stuff. Two different sources say to ground the ARINC 429 shield at source, destination, and at every 'break point' where additional receivers are added, in daisy chain fashion. Easy enough; I can handle that. There are 3 ARINC data runs between the ARINC module and the 430. Should each get its own shielded twisted pair, or would it be kosher to run 3 pairs in one shielded cable (and/or variations on that theme)? In various places, there are both single and bi-directional serial runs between/among the EFIS, 430, and other devices. In one case, they specify that a ground return *isn't needed* (obviously depending on system ground(s) between the EFIS & the 430). In most cases, they show a separate ground return wire, *within* the shield of the cable. Now, I'd understand that if the serial lines were 'balanced' (floating return), but all the serial ground returns are electrically bonded to the chassis of the AF4500S. Any noise imposed on the shield goes to exactly the same place inside the unit as the separate ground return. Seems silly to run an extra ground wire that's at the same potential as the shield. Any thoughts on this from those who have either designed or done the actual work on a/c using ARINC 429 and/or serial port technology? Thanks, Charlie ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message aeroelectric-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/AeroElectric-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/aeroelectric-list Browse Digests http://www.matronics.com/digest/aeroelectric-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.