just sell them with the low cost card with the upgrade option, provide the cheap card or youre in for a world of hurt on the support side. ship a preloaded industrial card to the 10% who need it, theyre probably already spending the extra dough on everything else anyway
On Tue, May 19, 2015 at 8:59 AM, Chuck McCown <[email protected]> wrote: > We hit –69 here in Utah. (and +116 too, 185 degree spread) > > http://www.deseretnews.com/article/116318/PETER-SINKS-UTAHS-COLDEST-SPOT.html?pg=all > > *From:* Bill Prince <[email protected]> > *Sent:* Tuesday, May 19, 2015 7:55 AM > *To:* [email protected] > *Subject:* Re: [AFMUG] Enclosure low temperature > > -40 is almost 100 degrees lower than we ever see inside any of our > cabinets. Just checking around our network, about the lowest I see anytime > in the last year has been ~~ 50 degrees. > > bp > <part15sbs{at}gmail{dot}com> > > > On 5/19/2015 6:50 AM, Chuck McCown wrote: > > I would think the worst case scenario is being cold soaked. > Power is off for a week. Power comes back on. -40 outside, the chip will > be –40. > > Pour some liquid butane on it to warm it up... > > *From:* Bill Prince <[email protected]> > *Sent:* Tuesday, May 19, 2015 7:47 AM > *To:* [email protected] > *Subject:* Re: [AFMUG] Enclosure low temperature > > How about actual data? For the last week, the ambient outdoor temp at this > site has been between 50 (night time), and 60 (daytime). The SiteMonitor > temp inside this 18x16x10 enclosure has been like below. So for at least > this situation, it's been running between 10 and 20 degrees above ambient. > The daytime temp is probably higher because of sun exposure. > > > bp > <part15sbs{at}gmail{dot}com> > > > On 5/19/2015 6:34 AM, Chuck McCown wrote: > > Back to the original question, need more data. It is a question of > physics. Jaime touched on it. > > Live load. > Ambient temp. > Thermal conductivity of the enclosure. > Surface area of the enclosure. > Wind speed at coldest temp. > Thermal convection currents inside the enclosure. > Thermal conduction currents inside the enclosure. > > Not trivial. > > Perhaps use some transistor grease and place a rectangular type metal > plate resistor on the memory. Add a tiny bit of foil and insulation. It > would take so little energy to get the memory up into the safe region that > it could probably happen in a few seconds. As has been mentioned, the > pre-heat on boot would certainly do that. Once booted, measure the > temperature and heat or not heat. Be a fun experiment. The memory thermal > mass is so small the resistor probably would have more thermal mass. You > could get a 50 degree rise in maybe 5 seconds with 1/4 watt if insulated > properly. > > > > > *From:* Forrest Christian (List Account) <[email protected]> > *Sent:* Monday, May 18, 2015 8:09 PM > *To:* af <[email protected]> > *Subject:* [AFMUG] Enclosure low temperature > > What is the lowest temperature that each of you would normally expect > to see in your enclosures? > > The reason I'm asking is that I'm in the process of developing up a few > new products. > > To date, all of the packetflux products are designed with components rated > -40 to +85C (I.E way cold to way hot). I'd like to retain this rating, > but I'm running into a minor snag: > > For storage, I'm planning on integrating a SD card (probably microSD) in a > socket. I only need a GB or so, and SD card memory is inexpensive at that > range. > > Unfortunately, all the reasonably priced SD cards are only rated down to > about -25C or -13F. which are about ~$3 in qty. "Industrial temperature > range" ones which are good down to -40C/F are available but they add at > least $30 to the cost for non-name brand, and even more for known brands. > When you're talking about a $100 end-user price, a $30 1GB SD card seems > excessive - and probably isn't even possible if I want to meet the $100 > price with some margin. > > So, I'm currently playing the 'what options do I have' game. I hate to > ship a product only rated down to -25C/-13F, but I know for at least a > large chunk of my customer base they never see below this temperature, > especially when you add a watt of power dissipation in the case with the > device. Which leads me back to my original question: What's the lowest > temperature most people would expect to see inside their enclosures. > > -- > *Forrest Christian* *CEO**, PacketFlux Technologies, Inc.* > Tel: 406-449-3345 | Address: 3577 Countryside Road, Helena, MT 59602 > [email protected] | http://www.packetflux.com > <http://www.linkedin.com/in/fwchristian> > <http://facebook.com/packetflux> <http://twitter.com/@packetflux> > > > > -- If you only see yourself as part of the team but you don't see your team as part of yourself you have already failed as part of the team.
