DIY_EFI Digest Thursday, 26 September 1996 Volume 01 : Number 288 In this issue: Re: Chip operating temperatures Re: Chip operating temperatures Re: Chip operating temperatures Re: Chip operating temperatures Re: Chip operating temperatures Re: D disease Re: Chip operating temperatures Re: Chip operating temperatures Re: Chip operating temperatures Newby help. Re[2]: Chip operating temperatures Digital Software Design Re: chip operating temperatures` Flex PCB Combustion chamber heat See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- From: "David M Parrish" Date: Wed, 25 Sep 1996 08:00:50 +0000 Subject: Re: Chip operating temperatures > From: "Mike Fahrion" > To take it one step further, it isn't terribly difficult to add a > heater circuit that will turn on power to a several watt resistor > when the ambient is below a certain threshold temp. Almost always, Woah! I think we're getting a bit far afield here. Heat is the real killer of electronics. I doubt that even -40C would be detrimental to most electronics, especially IC's. - --- David Parrish Here in Georgia, freezers don't even see -40! ------------------------------ From: "Mike Fahrion" Date: Wed, 25 Sep 1996 08:50:52 +0000 Subject: Re: Chip operating temperatures > > From: "Mike Fahrion" > > > To take it one step further, it isn't terribly difficult to add a > > heater circuit that will turn on power to a several watt resistor > > when the ambient is below a certain threshold temp. Almost always, > > Woah! I think we're getting a bit far afield here. Heat is the real > killer of electronics. I doubt that even -40C would be detrimental to > most electronics, especially IC's. > Sorry if I didn't explain myself clearly enough. This method is used to extend the cold temp range of standard commercial parts (0 degrees C - which can be a real problem). The original post refered to problems getting industrial spec'ed parts for the application. The heater circuit turns on power to a heating resistor (usually just a few watts) below a threshold temp (say 0 degrees C). Obviously it doesn't stay on indefinately - usually a bit of hysteresis is called for - say shut off the power at 5 degrees C. If the cost &/or availability of industrial or mil spec parts is a problem this is a great solution. One case where I used this solution was a design for use in Canada in an outdoor, unheated box. Several hundred of them have been working great with commercial spec parts for 3 years now. In that case delivery of a required part was 44 weeks vs stock for commercial spec, and 8 times the cost. That's not too uncommon.... - -mike mfahrion@xxx.com ------------------------------ From: Stephen Dubovsky Date: Wed, 25 Sep 1996 09:59:37 -0400 Subject: Re: Chip operating temperatures At 03:46 PM 9/24/96 -0500, you wrote: > [ snip ] > >Precisely, but lets understand: a digital part is just an analog circuit >in saturation [snip] You sound like an analog guy, I seem to remember that quantum physics says the world is digital (quantum levels) ;) (Im actually an analog/RF guy myself) S'am not looking for a flame'MD ------------------------------ From: "Robert Harris" Date: Wed, 25 Sep 1996 07:02:24 -0700 Subject: Re: Chip operating temperatures All I know is the crap that I find in repairing brand name PC's such as Packaged Hell, IBM, Dell, Gateway and Huo Fwung Dung Clones. The boards are dog shit and don't last unless dey ain't been fusted with. Since shop labor rates start at $45.00 an hour and my on site rate is $75.00 an hour, I really don't either try to repair them or determine wether there is a hairline crack or the component joint failed. I don't care - it don't work, its a tosser. The customer don't want to spend 45 bucks an hour - open end to find and fix a hairline crack on a PC. And I guess these must be the cheap radio shack boards because if you try bending them - they break rat now - real easy. Yes I have seen some wazoo mil-spec shit out there last forever - mostly used on airplanes older than the pilots. I am currently working a contract as an software integration engineer on a Methuselah bird, so if they is done right, I know they can last. Point is, was that the whole damned assembly is much more prone to failure from vibration and heat than the components themselves. Move it to human comfort zone and just avoid all the problems. Side note - ever see the sci fi "Plasma Storms" or whatever. That is sort of what the EMF environment is under the hood of a car. Each time a plug fires there is an extreme amount of energy generated from dc up into the microwave region. Used to call it spark gap transmission - thats how Marconi made his first wireless transmission across the Atlantic. There is a rotating ball of EMF around the alternator and kicking the starter over - does the word EMP mean anything? Give you a clue - it's the pulse from a nuclear event that fries the insides of devices electronic. It's simulated by a large current released thru an inductor - sort of like the collapsing field of a starter motor. If you can get your electronics out of that extremely hostile EMF environment - say by putting a grounded metal firewall between it and your computer, you will save one hell of a lot of time sorting between real data and random induced noise. Also don't forget to filter the DC as those lines carry a LOT of induced noise. > From: tom cloud > To: diy_efi@xxx.edu > Subject: Re: Chip operating temperatures > Date: Tuesday, September 24, 1996 4:58 PM > > Oh me, PCB's are *extremely* durable! You can often bend one almost > double without causing any damage. Hair line cracks are usually - ----- Cut here - personal comment follows ----- Q: What's the difference between Jane Fonda and Bill Clinton? A: She had the balls to go to Viet Nam Robert Harris - ---------- ------------------------------ From: cloud@xxx.edu (tom cloud) Date: Wed, 25 Sep 1996 10:15:59 -0500 Subject: Re: Chip operating temperatures >At 03:46 PM 9/24/96 -0500, you wrote: > >> [ snip ] >> >>Precisely, but lets understand: a digital part is just an analog circuit >>in saturation > [snip] > > You sound like an analog guy, I seem to remember that quantum physics >says the world is digital (quantum levels) ;) (Im actually an analog/RF guy >myself) > >S'am not looking for a flame'MD actually, they're teaching quantum stuff in freshman chemistry, gen'l physics, etc. now. You show me your electron and I'll show you mine, and if you can go from here to there without ever being anywhere in between I'll ..... ------------------------------ From: Dirk Wright Date: Wed, 25 Sep 1996 11:31:45 -0400 (EDT) Subject: Re: D disease On Tue, 24 Sep 1996, Johan Rodling wrote: > > AS far as I know the D-Jetronic is an analog MAP system built on transistors. Got one my self. It's primarly designed for 4- & 6- cylinders, but is also used on V12's with a booster amplifier for the injetors. It works in batch mode, so it fires a group three injectors three times (?) each cycle. I've got a bunch of patents on the D-Jet system. It's comprised of a bistable multivibrator, triggered by the extra distributor points, which then triggers a mono-stable multivibrator with variable pulse length. Pulse length is responisve to temperature, manifold vacuum, throttle position, and speed. The bistable multivibrator determines the start of each pulse, the mono-stable multivibrator determines the length of the pulse. The output of the bistable multivibrator and the monostable multivibrator are fed to a pair of AND gates, which in turn drive a pair of power transistors that turn the injectors on and off. For four-cylinder cars, injectors are fired in pairs once every other revolution, so that one of the pairs is fired early and the other is fired right on time. The result is that the ones that are fired early don't make as much power, especially at low revs, because the fuel is less well atomized. At high revs, it doens't make much difference, since the fuel only sits for a very short time on the early cylinders. Hope this helps. **************************************************************************** Dirk Wright wright@xxx.gov "I speak for myself and not my employer." 1974 Porsche 914 2.0 "A real hifi glows in the dark and has horns." 1965 Goodman House **************************************************************************** ------------------------------ From: Dirk Wright Date: Wed, 25 Sep 1996 11:54:39 -0400 (EDT) Subject: Re: Chip operating temperatures On Wed, 25 Sep 1996, Mike Fahrion wrote: > > > > Sorry if I didn't explain myself clearly enough. This method is used > to extend the cold temp range of standard commercial parts (0 > degrees C - which can be a real problem). The original post refered > to problems getting industrial spec'ed parts for the application. > The heater circuit turns on power to a heating resistor (usually just > a few watts) below a threshold temp (say 0 degrees C). Obviously it > doesn't stay on indefinately - usually a bit of hysteresis is called > for - say shut off the power at 5 degrees C. > I guess if you installed the chips under the heated driver's seat, you could kill a couple of birds with one stone.... **************************************************************************** Dirk Wright wright@xxx.gov "I speak for myself and not my employer." 1974 Porsche 914 2.0 "A real hifi glows in the dark and has horns." 1965 Goodman House **************************************************************************** ------------------------------ From: Gordon Couger Date: Wed, 25 Sep 1996 11:34:23 -0500 Subject: Re: Chip operating temperatures There are some resistors that increase resistance with temperature. I used some for a student lab where they were controling the heat with a computer and needed a lot of heat in a hurry but it needed to be fail safe. These resistors will put out a fast heat pulse and never get to hot to hold. Gordon Gordon Couger Senior Software Specialist Biosystems & Agricultural Engineering Dept. Oklahoma State Univ. 114 Ag Hall Stillwater, OK 74075 gcouger@xxx.edu >> > From: "Mike Fahrion" >> >> > To take it one step further, it isn't terribly difficult to add a >> > heater circuit that will turn on power to a several watt resistor >> > when the ambient is below a certain threshold temp. Almost always, >> >Sorry if I didn't explain myself clearly enough. This method is used >to extend the cold temp range of standard commercial parts (0 >degrees C - which can be a real problem). The original post refered >to problems getting industrial spec'ed parts for the application. >The heater circuit turns on power to a heating resistor (usually just >a few watts) below a threshold temp (say 0 degrees C). Obviously it >doesn't stay on indefinately - usually a bit of hysteresis is called >for - say shut off the power at 5 degrees C. ------------------------------ From: cloud@xxx.edu (tom cloud) Date: Wed, 25 Sep 1996 15:05:28 -0500 Subject: Re: Chip operating temperatures >There are some resistors that increase resistance with temperature. I used >some for a student lab where they were controling the heat with a computer >and needed a lot of heat in a hurry but it needed to be fail safe. These >resistors will put out a fast heat pulse and never get to hot to hold. > >Gordon > >Gordon Couger Senior Software Specialist >Biosystems & Agricultural Engineering Dept. Oklahoma State Univ. >114 Ag Hall Stillwater, OK 74075 >gcouger@xxx.edu Nichrome, tungsten, and most other resistance wires have pos. tempcos but I don't think they have a steep enough curve to be self-limiting in such an application as this. Light bulbs are tungsten and have several neat uses: constant current sources, current limiters, heaters, -- and ... light sources. If I were going to make a heater for an electronic hootis for my car, I'd want to be sure that it didn't drain my car's battery. If it didn't have to be on all the time, I'd make it come with the ignition switch -- but then it'd have to have a real fast rise, and that would mean it could also be destructive if it were not controlled. There are flat, flexible heaters encapsulated in silicone made especially to bond to PCB's and that's what I'd try to use, as that would heat only the control circuitry -- which would require less heat as less would be lost through the case to the outside. There are metal cased resistors (check Dale Electronics in an electronics catalog -- e.g. Newark) that bolt to metal. Could use one of those on an aluminum plate. Put either one in the collector of a common emitter transistor amp, put a thermistor mounted to the same plate in the base circuit and voila' a self-regulating heater. Could also just buy a small thermostat and use it. ------------------------------ From: Jamie Cairns Date: Thu, 26 Sep 1996 10:48:14 +1200 Subject: Newby help. Hi all, I am new to this mailing list, but would like to know of or hear from anyone using the Motorola HC11 for any data-gathering or full blown fuel injection applications. I am currently finishing a Computer Science degree, so I've only looked at the possibility of doing this thing and sketched out some avenues so far - to busy to get anywhere with it. I am intending to create a fuel injection system for use with the Datsun L series motor (4 cyl first, then 6). We have used the HC11 at varsity here, so I am reasonably familiar with it, and have invested the $NZ25 in an HC11F1. Now is the time to start PCB layout design. I do not think of myself as being proficient with hardware design - software is my forte, so I would be grateful for any advice anyone could give me on this subject, in particularly my hardware/usage requirements. Thanks, Jamie Cairns. ------------------------------ From: dzorde@xxx.au Date: Thu, 26 Sep 96 10:48:10 Subject: Re[2]: Chip operating temperatures ______________________________ Reply Separator _________________________________ Subject: Re: Chip operating temperatures Author: diy_efi@xxx.edu at INTERNET Date: 9/25/96 4:45 AM Oh, and the way to keep from replacing the radiator because you forgot to add antifreeze is to use an air cooled engine;) (Im a 911 owner) Or move to a warmer country ------------------------------ From: "Robert Harris" Date: Wed, 25 Sep 1996 23:26:49 -0700 Subject: Digital Software Design Anyone up for opening a thread to deal with developing a simple software algorithm following good engineering practices - i.e. blatantly stealing anything that works? Have worked out some ideas, but would like to open a forum and reach a consensus. I'm sure many of us have fragments that we could put together and make a great program. - ----- Cut here - personal comment follows ----- Q: What's the difference between Jane Fonda and Bill Clinton? A: She had the balls to go to Viet Nam Robert Harris - ---------- ------------------------------ From: talltom Date: Wed, 25 Sep 1996 23:33:38 -0700 (PDT) Subject: Re: chip operating temperatures` I'm going to take BOTH sides on this one! Generally I don't see to much problems with pcb's, except in cars. One of my customers has an electronics co that has about 8000 ft of pcb's, and little problem with pcb's. On the other hand, I'm certain we could come up with a few rooms full of auto pcb's with cracked traces, specifically Mercedes temp control. I don't know what MBZ used for a substrate, but do know that the usual fix is to eyeball for and solder up cracks in trace.(Mine is mechanical, thank you) One thing I've never seen is the failure of the printed circuits on the what appears to be some type of mylar used in many dash assembly's. Anybody know what the material is? And the difference in expansion rate between it and copper? I'm guessing that either the expansion rate is similar or copper exapnds more than the film, or I'm full of it. "a society that will trade a little freedom for a little order deserves neither" Thomas Jefferson Clinton doesn't want anything Hitler didn't have. What do you get with Bob Dole, Bill Clinton, and Dolly Parton in the same room? Two boobs and a country singer! Harry Browne for president 96! Talltom ------------------------------ From: "Hans Hintermaier" Date: Thu, 26 Sep 1996 10:30:45 MET Subject: Flex PCB Talltom Wrote: > One thing I've never seen is the failure of the printed circuits on the >what appears to be some type of mylar used in many dash assembly's. >Anybody know what the material is? And the difference in expansion rate >between it and copper? I'm guessing that either the >expansion rate is similar or copper .... Hi Tom, I once worked as camera service technician at Olympus and Konica, they only use in their modern compact cameras flexible PCB's. The material was Polycarbonat, painted with an extremly durable, transparent gloss, maybe Polyurethan based, which stabilized the PCB a lot. Plastics expand generally much more than metals (I think) There were nearly no failures caused by cracked traces in those 4 years I was working there. Regards Hans hiha@xxx.de Munich / Germany ------------------------------ From: talltom Date: Thu, 26 Sep 1996 01:45:38 -0700 (PDT) Subject: Combustion chamber heat I've noticed a little discrepency here in relation to combustion chambwer heat. It seems that some say it's necessary to go over rich to cool and prevent preignition/detonation. Others say that thermal barrier coatings are the neat trick, which would make the combustion chamber hotter, and to me more knock prone. I've heard it said that eng's with aluminum heads will make 30-40 hp less than same with cast iron heads.. Todd said he had to go rich on aircooled to keep from self destruction. My question is why, meltdown or preignition/detonation? If it's preignition/detoation wouldn't thermal barrier coatings make it worse?(barring carbon deposits) Hate to mention it, but yes I agree that the heat generated will be more effective in the cylinder, but art what cost in the way of ign timing penalties?? Really do hate to open the thermodynamics bag of worms again, but it seems everybody I know with air cooled says they're at a disadvantage, the aluminum guys say they're at a disadvantage, and the cast iron crowd seems to think the aluminum guys are ahead. Somebody's screwed! Question is who? (Either way I win, I have cast iron and aluminum heads, and air cooled is out of the question, unless you're talking Lister diesel) "a society that will trade a little freedom for a little order deserves neither" Thomas Jefferson Clinton doesn't want anything Hitler didn't have. What do you get with Bob Dole, Bill Clinton, and Dolly Parton in the same room? Two boobs and a country singer! Harry Browne for president 96! Talltom ------------------------------ End of DIY_EFI Digest V1 #288 ***************************** To subscribe to DIY_EFI-Digest, send the command: subscribe diy_efi-digest in the body of a message to "Majordomo@xxx. 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