On 3 Jan 2009, at 16:17, John Denker wrote: > They don't care what local units are used to communicate > between the tuner and the CDI head. It could be "gallons" > as Torsten mentioned. > > The existing code uses [0 ± 10] gallons for the left/right > needle and [0 ± 3.5] gallons for the up/down needle. The > xml instrument designers have come to terms with this. > Some comments here and there, documenting this convention, > wouldn't hurt. IMHO nothing more than comments is worth > bothering with.
> On the scale of things, this is not "broken". There are > dozens upon dozens of things far more broken than this. Except that, it caused the GPWS code to misbehave, and I am enough of pedant that I am not prepared to accept an arbitrary scale of gallons just because that's what's gone before. My dislike of magic numbers / units / scales is really quite intense. I understand that from a strictly pragmatic point of view, the easiest thing would be to just do one more magic conversion in the Mk-VIII code, but, yuck. > Not a great idea, for reasons discussed below, including > the fact that it fails miserably for RNAV units. Well, in the medium term, I have another idea on that front, but I really want to get the GPWS working better, so that's a discussion for another day. For now, let's just say that navradio is a very bad fit for RNAV or GPS units, and that things there will have to change, but not as part of this work. One thing at a time, and all that. > The existing scheme, which puts out a normalized > full-scale deflection, is almost realistic and has > proven perfectly adequate over the years. The > choice of what the normalization constant should > be is a private matter between the tuner-designers > and the CDI-designers. Fussing over private > matters doesn't do the users much good. Except it's normalised to these somewhat arbitrary values, so rather than just agreeing on some bad values because they exist, why not add/ migrate to some that actually make sense, and stop people (eg, Syd) guessing what full-range is. I.e, let's just normalise to [-1.0 .. 1.0] and be done with it. (Except, as Torsten just noted, the values can probably go slightly beyond that, since any clamping should be done at the panel-instrument level, not the receiver level). James ------------------------------------------------------------------------------ _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
