On 7/17/2011 12:48 AM, dave wrote: > On Sun, 2011-07-17 at 01:30 +0000, James Reed wrote: > >> You can do the same thing electricians do in an explosion-proof enclosure. >> The idea of an explosion proof enclosure is not to prevent the vapors from >> entering the enclosure, but to contain any explosion that could occur inside >> the enclosure. ( Kind of re-assuring, isn't it?) When these enclosures have >> threaded openings, they have 2 to 4 times as many threads as the >> non-explosion proof openings, and they have larger or square openings with >> large flanges and usually gaskets. In order to meet code, the conduit which >> leads to these enclosures have to have a conduit seal with putty or epoxy in >> them to prevent the flow or explosion from/to other places. It's actually >> more complicated than this, but this is the kind of detail that you will >> want to know. >> >> You don't have to go explosion proof, but can copy their techniques. >> >> I would be leery of putting batteries in a totally enclosed box, though. >> >> >>> Date: Sat, 16 Jul 2011 18:58:48 -0400 >>> From: e...@dc9.tzo.com >>> To: emc-users@lists.sourceforge.net >>> Subject: [Emc-users] Using a PC in extended temperature ranges and mobile >>> application >>> >>> >>> Hi Guys.. >>> >>> I am considering using EMC2 (or part of it) in a mobile application that >>> defines the term "rugged". >>> >>> The application itself is pretty simple so I am not worried about the >>> software. I am worried about the survival of the hardware. >>> >>> The equipment will be mounted in a box on a piece of drilling >>> equipment. Power will be supplied via a diesel engine driving an >>> alternator into a set of batteries. >>> >>> The drilling equipment is rotary - no impact - so the vibration should >>> be reasonable if I shock mount the control panel. However the machine >>> will only be used once in a while. >>> >>> This machine will live outside year around. When it is not being >>> used, the machine will be un-powered so I have no way of putting a panel >>> heater in the box to keep out condensation. I'm thinking about using >>> some type of desiccant system?? to keep the humidity down in the panels >>> to avoid a condensation problem. >>> >>> I'm really not concerned about the higher range of temperatures since >>> there will be a roof over the control panel so I should be able to keep >>> the sun off it. I am mostly concerned about the low end of the >>> temperature range. They could be >>> using this drilling machine in temps as low as 20 degrees F or so. >>> They will expect to be able to start up the engine, run it for 5 minutes >>> or so and then flip on the controls and have them function properly. >>> This might be after the machine has been >>> sitting for a few months outside in places like the Rocky Mountains in >>> Colorado.... >>> >>> I'd like to use as many off the shelf devices as possible - PC boards >>> etc... if possible. >>> >>> Being a typical customer, they want to keep the costs down but they also >>> want it to work and operate reliably. >>> >>> I've had good luck using conventional industrial controls on machines >>> that operate outside, but I have always been able to include a panel >>> heater to minimize condensation issues. >>> >>> Do you guys have any suggestions? >>> >>> Dave >>> >>> > That IS a demanding application: > Problems: > a. temp range -30 to -40 F to maybe 110 F. > b. the need to be up and running in 5 min implies > pretty steep temp gradients upon start-up if it is cold. > c. good cooling in the summer. > d. keep alive and probably desulfation for the > batteries. > e. hard disks really don't turn very well when cold so > some kind of bulk semiconductor memory is probably > indicated. > > Still it does sound like a challenge and should keep life from > getting dull. > > Good luck. > > Dave > > >
The operating temp range is probably 20-120 degrees F. If it is below about 20 degrees they will not be able to drill since the system requires cooling water. They could probably add antifreeze but below 20 degrees, drilling is probably not practical. The batteries are their problems...fortunately. :-) They will probably use AGM batteries in order to eliminate some storage issues. I was thinking of using either a CF card as a "hard drive" or go with a solid state hard drive to eliminate the rotating hard disk vulnerability. >>does sound like a challenge and should keep life from getting dull. Yes, it seems like once I put a control system together for a customer I tend to "own" it forever. I get calls from customers 5+ years after an installation asking for help or advice. I am surprised how reliable most of the equipment is. Usually their issues are mechanical or maintenance related (didn't grease the bearings etc). LCD screens are starting to burn out now, but after 3 or 4 years of continuous use they don't seem to mind paying for replacements. Dave ------------------------------------------------------------------------------ AppSumo Presents a FREE Video for the SourceForge Community by Eric Ries, the creator of the Lean Startup Methodology on "Lean Startup Secrets Revealed." This video shows you how to validate your ideas, optimize your ideas and identify your business strategy. http://p.sf.net/sfu/appsumosfdev2dev _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
