You'll have to register on the site, but you can find NFPA 1127 at https://www.nfpa.org/codes-and-standards/all-codes-and-standards/list-of-codes-and-standards/detail?code=1127. If that link doesn't work for you, you can search 1127 from https://www.nfpa.org and then click on "more information about..." from the page for ordering the book.
Dan Crank On Fri, Mar 15, 2019 at 10:11 PM Bdale Garbee <[email protected]> wrote: > "David W. Schultz" <[email protected]> writes: > > > Both NFPA 1122 and 1127 require that launch systems include a removable > > safety interlock in series with the launch switch. TRA uses NFPA 1127 as > > their safety code and NAR requires following the NFPA codes at all NAR > > launches. So this is a problem. > > I wasn't aware that a removable interlock was an explicit requirement. > I just looked and couldn't find the current NFPA text anywhere online. > I'd like to read the actual text... any idea where I can find it? > > > The fix is to replace the silly guarded toggle switch with a key > > switch for safe/arm. > > Right, pretty easy change. I'll look at the details tomorrow. > > > Put a lanyard on the key so the LCO can hang it around his neck when not > > in use. (Stash a spare key inside the case.) > > Sigh... all part of the reason I personally detest key switches. My > observation is that key switches get turned, but the key rarely gets > pulled out in practice. But .. [sigh] .. rules are rules. > > > Those switch connections make me nervous. They connect unprotected GPIO > > pins to parts that are being handled by the user. Sure the switch body > > will provide some protection from ESD but how much? A series resistor > > would help a lot. Large enough to limit currents in the ESD diodes on > > the GPIO pins but small enough to work with the internal pullups. > > Sure. In several years of use, we've seen no issues with zapping the > SOC's in-built ESD protection on the protos, but resistors are cheap and > I can easily add them to the board revision I'm preparing to send out to > fab. Thanks for the suggestion. > > > Oh, I thought that the FCC prohibited encryption for amateur radio: > > 47 CFR 97.309(b) Has that changed? > > 97.309(b) does not apply because we're not encrypting the content, thus > we are in no way "obscuring the meaning of any communication". What > we're doing is appending a crypto checksum to each packet to > authenticate the link. That's been a common mechanism on amateur radio > control links for a long time. > > The closest thing I can find to an official pronouncement about this > is in the ARRL comments in response to RM-11699, which they opposed. > In those comments, they indicate that conversations with the FCC led to > agreement that encryption for authentication on things like repeater > control links was already allowed, and thus not a reason to accept the > request that lead to that RM. > > I'll note in passing that there's also 97.215(b), though I don't think > the FCC had model rockets in mind when discussing telecommand of model > craft. Sure feels like an analogous use, though. > > Bdale > -----BEGIN PGP SIGNATURE----- > > iQIzBAEBCgAdFiEEhHDyCwYlkhh8unuzOpNhlsCV2UEFAlyMaUUACgkQOpNhlsCV > 2UH5YhAAvZgOpMXkIoeiJ6io9efj7eT47sw6CqFjjYaL2K/8bxA7oZbpikjEUFhx > CSCe87eS9MEu6rbw6I0kJcfe/y4tVRjrhSUiMOkm9mGDyHWLJvePNkL0ceyW10cW > xyG7rBlthhJNc4XmzH5vI2VrRRpuB+36M8P9hMDZEvlfNr2E85VCXl9BX8EgRoqX > 1EHT+nlZa/yO+vhEq4MTrQ0oLLqC1Rm+Z8BT2lefygAyDFE03laCT4qcz+wM0Vwk > 5Q8J71H+3Eq0qQmweU/I7nrBYsMGdgGEGiPyYczi2iVU7GsbVOJ2Tgi8awEIksTU > HrwhP3i6YjEvZNGXj4R6mM9d2AccjlWRcc+E1E9n2ogH6H5MFZ15b1GI/4T36tyT > GjWJhBb81vRzCjhbyAXd5Y5YjXWUz6TYiUW3hqH+PemGEmavkJuVpAll7nCI6YjU > 8UkbtSR7JH92BeECPFdXBtYMEbEP9nBLwCS02Pnh2IfnQooTQJWn+ouRLrfmcgjN > DTvTjWHOYbjbJpHfGa9IUlqDTO+94C2+hakeQnFfMtkO4QiJX0A62v2vVJwI/TC1 > sObzq034tH8ClDE4VGZpdHhq+X4AZ6gbJPzOi2mAtevfKS/ZpxMVq5ZrE6Hr4k/v > qHuikrZTZ1vnmraqEw2jVjCP4OUsi4hfUZVEM5Bl6AF09G14GrU= > =AY2F > -----END PGP SIGNATURE-----_______________________________________________ > altusmetrum mailing list > [email protected] > http://lists.gag.com/mailman/listinfo/altusmetrum >
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