@xxx.edu Sat Aug 12 10:11:28 1995 Date: Sat, 12 Aug 1995 05:00:01 GMT @xxx.edu @xxx.za Subject: Majordomo file: list 'diy_efi' file 'archive_num_8' -- >From Diy_Efi-Owner Mon May 9 22:59:01 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA21881; Mon, 9 May 94 22:59:01 GMT Received: from aztec.al.bldrdoc.gov by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA21875; Mon, 9 May 94 18:58:59 -0400 @xxx.edu> Date: 9 May 1994 17:00:34 -0700 @xxx.gov> Subject: RE: Miniboard is the way to go... for now To: DIY_EFI Sender: Diy_Efi-Owner Precedence: bulk Reply-To: DIY_EFI I'm sorry, I can't figure out how to include previous text in a reply, but the origional poster states that the miniboard is the way to go. I almost agree, but from what I can determine, if the miniboard is used with the E2 suffix of the 6811, it only has 2k for program development and 512 bytes of ram. While it might be possible to build a fuel injection system in only 2k, Trust Me, for a development system you want as much ram and eprom available. 32K ram chips and eproms are about $5 each, and 6811 development boards that can take a 32K ram and a 32k eprom can be found for around $100. I personally am taking this route, after having developed a 'senior project' quality distributorless ignition system using the E9 version of the 6811 in single chip mode (12K eprom, 512 bytes ram, 512 bytes EEPROM). FYI: Cheep, fast, 32K static ram chips can be made battery backed up (10 years) for about $12 thanks to Dallas Semiconductor's Smart Sockets. This is nice for program development. As soon as I finish moving, I will publish my code/hardware for this ignition sytem. It falls in line quite nicely with what we are trying to do, is a good starting point for a DYI-EFI system, and I'd be interested in the net's comments. - Steven Ciciora >From Diy_Efi-Owner Mon May 9 23:11:17 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA22082; Mon, 9 May 94 23:11:17 GMT Received: from hp-cv.cv.hp.com by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA22076; Mon, 9 May 94 19:11:15 -0400 Received: from hp-pcd.cv.hp.com by hp-cv.cv.hp.com with SMTP (1.36.108.7/15.5+IOS 3.22+CV 1.0ext) id AA07466; Mon, 9 May 1994 16:11:12 -0700 Received: from by hp-pcd.cv.hp.com with SMTP (1.37.109.8/15.5+IOS 3.22+OM+CV 1.0) id AA28652; Mon, 9 May 1994 16:11:10 -0700 @xxx.com X-Openmail-Hops: 2 Date: Mon, 9 May 94 16:10:36 -0700 Message-Id: @xxx.edu> Subject: RE: Miniboard is the way to go... for now Cc: DIY_EFI Sender: Diy_Efi-Owner Precedence: bulk Reply-To: DIY_EFI Subject: RE: Miniboard is the way to go... for now @xxx.edu) at HP-Corvallis,unix1 Date: 5/9/94 5:00 PM I'm sorry, I can't figure out how to include previous text in a reply, but the origional poster states that the miniboard is the way to go. I almost agree, but from what I can determine, if the miniboard is used with the E2 suffix of the 6811, it only has 2k for program development and 512 bytes of ram. While it might be possible to build a fuel injection system in only 2k, Trust Me, for a development system you want as much ram and eprom available. 32K ram chips and eproms are about $5 each, and 6811 development boards that can take a 32K ram and a 32k eprom can be found for around $100. I personally am taking this route, after having developed a 'senior project' quality distributorless ignition system using the E9 version of the 6811 in single chip mode (12K eprom, 512 bytes ram, 512 bytes EEPROM). FYI: Cheep, fast, 32K static ram chips can be made battery backed up (10 years) for about $12 thanks to Dallas Semiconductor's Smart Sockets. This is nice for program development. As soon as I finish moving, I will publish my code/hardware for this ignition sytem. It falls in line quite nicely with what we are trying to do, is a good starting point for a DYI-EFI system, and I'd be interested in the net's comments. - Steven Ciciora ******************************************************************************* This is precisely the argument for using the F1 board. It handles more memory and is modular in design. The ignition sounds very interesting and I would love to see what you've done. Cary McCallister >From Diy_Efi-Owner Tue May 10 04:47:48 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA23092; Tue, 10 May 94 04:47:48 GMT Received: from Rosie.UH.EDU by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA23086; Tue, 10 May 94 00:47:47 -0400 Received: from Jetson.UH.EDU by Jetson.UH.EDU (PMDF V4.2-11 #5185) id @xxx.EDU>; Mon, 9 May 1994 23:47:40 CDT Date: Mon, 09 May 1994 23:47:40 -0500 (CDT) @xxx.EDU Subject: Miniboard, with minimemory! To: DIY_EFI @xxx.EDU> @xxx.edu" Mime-Version: 1.0 Content-Type: TEXT/PLAIN; CHARSET=US-ASCII Content-Transfer-Encoding: 7BIT Sender: Diy_Efi-Owner Precedence: bulk Reply-To: DIY_EFI Hmm. Good point Steven, 2k is not enough to get the job done. After reading the miniboard manual at the ftp site, I realize how serious a limitation this is. The miniboard is still a great device, perhaps it could be used for some auxillary part of the EFI system. To Cary McCallister, Ok, well I guess the F1 board is really the only logical solution if we want to avoid designing our own microcontroller. Messages sure are thinning out here... Finals anyone? >From Diy_Efi-Owner Tue May 10 05:09:02 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA23143; Tue, 10 May 94 05:09:02 GMT Received: from Rosie.UH.EDU by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA23137; Tue, 10 May 94 01:08:59 -0400 Received: from Jetson.UH.EDU by Jetson.UH.EDU (PMDF V4.2-11 #5185) id @xxx.EDU>; Tue, 10 May 1994 00:08:47 CDT Date: Tue, 10 May 1994 00:08:47 -0500 (CDT) @xxx.EDU Subject: Crank position sensor To: DIY_EFI @xxx.EDU> @xxx.edu" Mime-Version: 1.0 Content-Type: TEXT/PLAIN; CHARSET=US-ASCII Content-Transfer-Encoding: 7BIT Sender: Diy_Efi-Owner Precedence: bulk Reply-To: DIY_EFI Assuming we will hammer out the controller, the first and most basic sensor we need is the crank position sensor. If we are going to make a true SEFI system with distributorless ignition, a highly accurate crank position sensor is a must. But how? I've seen some setups using magnets, but how can these be installed? Do holes need to be drilled in the harmonic balancer with little magnets placed in them? That's the only way I can come up with. The racing setups are great, but we have to install this on our engine with minimal (hopefully) modification. >From Diy_Efi-Owner Tue May 10 05:48:11 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA23222; Tue, 10 May 94 05:48:11 GMT Received: from uahcs2.cs.uah.edu by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA23216; Tue, 10 May 94 01:48:10 -0400 Received: by uahcs2.cs.uah.edu (Smail3.1.28.1 #3) id m0q0kfq-0000zBC; Tue, 10 May 94 00:48 CDT @xxx.edu> Date: Tue, 10 May 94 00:48 CDT @xxx.edu (Ken King) To: diy_efi Subject: DIGEST FORMAT? (pleasePLEASEpleasePLEASE) Sender: Diy_Efi-Owner Precedence: bulk Reply-To: DIY_EFI greetings: the subject says it all. can we get the list in digest format? i'm getting a bit tired of hacking 20-some-odd lines off each message i want to save... later, kc >From Diy_Efi-Owner Tue May 10 06:12:04 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA23258; Tue, 10 May 94 06:12:04 GMT Received: from uahcs2.cs.uah.edu by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA23252; Tue, 10 May 94 02:12:02 -0400 Received: by uahcs2.cs.uah.edu (Smail3.1.28.1 #3) id m0q0l2w-00011mC; Tue, 10 May 94 01:12 CDT @xxx.edu> Date: Tue, 10 May 94 01:12 CDT @xxx.edu (Ken King) To: diy_efi Subject: requirements... Sender: Diy_Efi-Owner Precedence: bulk Reply-To: DIY_EFI greetings: some additions to the 'outline' requirements sent out some number of days ago 4.3 water temp (in block, so we know what the temp is prior to the thermostat opening...) 4.9 full engine status (including oil temp/pressure, tranny temp/pressure, rpm, outside temp,...) these are for display & recording (see 8.1) 4.10 knock sensor (or, as was suggested to me some time ago, cyl. pressure sensors (wrap 'round spark plugs...)) 7.2.1 voltage outputs (as well as switched - wire-or'd to a *big* red lite) for driving gagues (stock, aftermarket or custom...) 7.4 switch/solonoid controllers (for water injection, nitous, alky,...) 7.5 tach, speedo, odo,... (mpg, miles-till-empty,...) trip computer stuff, we'll have damn near all the input needed... (try a recent top-of-the-line jeep for a clue... when my wife got one, the cost to finish my project just about doubled): :( :) 8.0 onboard memory - good for error code storage (w/ a few seconds of data from either side of the event), data points for quarter mile (or 1/8 in my case) runs - things like being able to plot oil pressure vs rpm... (that should have been 8.1) 8.0 debug/memory 8.2 breakpoint debugger - to keep a list of what happened (event flags, data values) in a circular buffer w/ programmable 'ends' (ie everything bfore the event happened, some data before & some after,...) historical note - on my last embedded controller (experiment controller flight box for nasa) we had an ASIC w/ 1024 'events' and the ability to snoop the busses (2 cpus,...) it was ***REAL*** handy. might be a bit hard to implement, but s/w monitor (laptop) might suffice... just some thoughts... my desires are to build a turbocharged (or paxton/vortech) inline 6 w/ efi and electronic (adaptive) ignition. included in the ignition is the ability to milk the most out of each cyl, independantly of the others. therefore, my list of wants/desires are as follows: - work with boost (incl. ignition controller) - include load profile of engine (for lockup converter control (tranny)) - possible control harness for electrically controlled 4spd auto-tranny - adaptable/scalable (4 cyl, 6 cyl, 8 cyl, different rpm limits...) the idea was to have a cpu that was available w/ many clock speeds, so we only needed to buy what our application needed... - options for pre-ignition chekcs (ie not start cranking engine until the fuel rail is pressurized, pre-luber/oil pressure switch...) - ignition switch for startup (ie no spark until after tdc, for hi-compr engines...) - options for linear 02 sensor (not just those lousy 02 switches...) - price of under $500 (several companies can help you 'fix' a scavanged ecu for about that price (assuming a reasonable salvage 'fee') that about does it for now... later, kc 69 nova (all over the garage) 77 aspen (slant 6) rusting in driveway :) >From Diy_Efi-Owner Tue May 10 06:37:18 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA23293; Tue, 10 May 94 06:37:18 GMT Received: from [202.14.102.1] by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA23287; Tue, 10 May 94 02:37:14 -0400 @xxx.5) id SAA27435; Tue, 10 May 1994 18:32:20 +1200 @xxx.nz> @xxx.nz> Subject: Re: What can we measure To: DIY_EFI Date: Tue, 10 May 1994 18:32:20 +1200 (NZST) X-Mailer: ELM [version 2.4 PL21] Content-Type: text Content-Length: 981 Sender: Diy_Efi-Owner Precedence: bulk Reply-To: DIY_EFI My post of the other day was intended to spark discussion of what alternative sensors are available that might be utilised in a small volume EFI system. For example. Exhaust temperature varies with mixture. Leaner being hotter. Can this be utilised for feedback ? MAS sensors are more expensive than MAF, but are a direct measurement. What alternative methods are there for measuring mass other than the constant temp hot-wire anenometer ? Any lateral thinkers out there ? PS. I'll be using leaded gas because that's what they sell around here. We have 96 octane leaded and a 91 octane "unleaded" that still has too much lead for catalytic converters. Incidently, there was an unleaded "unleaded" sold here for a while and it burnt my (and a lot of other people's) valves out real quick before it was withdrawn from the market. I don't know if the unleaded vs. valve life issue was a farce or not in the US but I'll admit to being a bit shy of unleaded gas for a while. Steve. >From Diy_Efi-Owner Tue May 10 07:14:18 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA23338; Tue, 10 May 94 07:14:18 GMT Received: from ZEUS.TAMU.EDU by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA23332; Tue, 10 May 94 03:14:16 -0400 Date: Tue, 10 May 1994 2:14:15 -0500 (CDT) @xxx.EDU To: diy_efi @xxx.EDU> Subject: RE: crank sensors Sender: Diy_Efi-Owner Precedence: bulk Reply-To: DIY_EFI i think that drilling into the Harm. Bal. would be a mistake. I am not sure, but i think this could damage the balancing of the H. B.? ? Perhaps, a better way of getting the timing down would be to use a seperate plate bolted to the balancer's bolt containing the magnets to be picked up with externally mounted sensor just like you speak of. i have seen similiar systems in Summit and H.R. mag. another question: have we decided on just how many sensors will be needed for input to the system controller? -tom >From Diy_Efi-Owner Tue May 10 11:57:54 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA23735; Tue, 10 May 94 11:57:54 GMT Received: from mail.swip.net by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA23729; Tue, 10 May 94 07:57:49 -0400 Received: by mail.swip.net (8.6.8/2.01) id NAA07636; Tue, 10 May 1994 13:56:12 +0200 Received: from cc:Mail by lotussun.lotus.se id AA768603232 Tue, 10 May 94 13:53:52 Date: Tue, 10 May 94 13:53:52 @xxx.net @xxx.se> To: DIY_EFI Subject: Intro: New member Sender: Diy_Efi-Owner Precedence: bulk Reply-To: DIY_EFI I'm very much game, although I'm not sure I can contribute too much in the company of such learned gentlemen/(ladies?), more than posting questions that are way below the discussion level of this list. One problem is knowledge level, the other one is that I'm PC/Windows based using Lotus Notes, Lotus cc:Mail, to Internet thru a UUCP gateway and that gateway does not always behave the way I want it to. Hopefully my subscription request has gone thru so I can at least receivethe postings (which works for the hotrod list). We'll see... Whatever, here goes: I work for Lotus Development as a marketeer, based in Stockholm, Sweden. The long winters up here are ideal for projects like the following: I am building a Harley for strip/street activity where I want to run a complete electronic management system for both fuel injection and ignition. The system is to be adjusted from a laptop PC. The strange firing-order of the HD motor makes buying an OEM system a bad idea. You either need a system that can manage a 16 cylinder engine (cutting out 14) or have somebody like Electromotive offer me two single cylinder FI modules for the price of two. No, I was told that they cannot modify their software due to certain legalities involved. Whatever, the cost of a dual setup far exceeds my budget (even the single setup more than stretches it) and the question is always "For that price, should I go thru the trouble of making it myself" and I am certain that in this case the answer is clearly "yes". The biggest hurdle is the programming side of the microcontroller, but "with a little help from my friends"... There are a few different ways of approaching this but by using common sense, it's obvious that any EFI system will always far outperform a carburated system even if the EFI system is not optimal. After having spent quite a few hours chasing and going thru as much technical doc's (and sales info) as I can find, I am looking at the following setup regarding sensors. What I'm looking for is a second opinion for a go or no go since I really need to choose a path for continuing the work done so far. The basis for my drawing board setup regarding sensors is simplicity, forget calculating load and air mass thru temperature, MAP, throttle positioning etc. I would like to use an airmass sensor from the Bosch L-Jetronic systems that I understand have temperature compensation built into it. (Airflow restrictions don't come into play as the HD motor would displace 80 cu.in. running at 6500 rpm at the most). I look at running separate sensors for RPM and crankshaft position on the front belt pulley that is attached to the crank (I would love to be able to kickstart this motor, tough proposition but I have some ideas). Oxygen sensor in the exhaust for closed loop management on that part and topping it off with a throttle position sensor and maybe a knock sensor. Driveability is not a factor (i.e. rough running at warm-up is OK, no compensation needed for AC etc.). There's a lot of reasons behind these choices but it would take a few pages to explain. I would like a second opinion from someone who has been there: all I need is a simple "yes" or a "no - wrong track, you also need a so-so sensor" at so I can finally get started working on this system. Reg's Par Willen __________________ @xxx.SE >From Diy_Efi-Owner Tue May 10 13:02:15 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA23967; Tue, 10 May 94 13:02:15 GMT Received: from slopoke.mlb.semi.harris.com by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA23961; Tue, 10 May 94 09:02:13 -0400 Received: from billy.mlb.semi.harris.com by slopoke.mlb.semi.harris.com (4.0/SMI-4.0) id AA10969; Tue, 10 May 94 09:02:11 EDT Received: by billy.mlb.semi.harris.com (4.1/SMI-4.1-jmb) id AA00988; Tue, 10 May 94 09:02:10 EDT Date: Tue, 10 May 94 09:02:10 EDT @xxx. Swonger) @xxx.com> To: DIY_EFI Subject: RE: crank sensors Sender: Diy_Efi-Owner Precedence: bulk Reply-To: DIY_EFI What about the other end? Every engine has a nice, big flywheel or flex plate (which all have a multitude of teeth you could even pick a pulse train off of). The indexing of TDC might be trickier. On the flex plates there are usually some uniquely-positioned holes which would serve. If you want something to bolt onto the front, though, I guess a chopper wheel is the way to go. A thin steel plate between the crank pulley and the balancer could be added without disturbing the balance. Holes to interrupt an optical or magnetic path. Is the intent to produce something universal? That might be a lot tougher. Most of the aftermarket crank trigger kits are universal - will fit any small block Chevy. >From Diy_Efi-Owner Tue May 10 15:18:09 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA24951; Tue, 10 May 94 15:18:09 GMT Received: from stdvax.gsfc.nasa.gov by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA24945; Tue, 10 May 94 11:18:07 -0400 Date: Tue, 10 May 1994 11:16:31 -0400 (EDT) @xxx.GOV (DIRK BROER) @xxx.GOV> Subject: A Proposal To: DIY_EFI X-Vmsmail-To: @EFI Sender: Diy_Efi-Owner Precedence: bulk Reply-To: DIY_EFI I've been following all the posts and have come to one conclusion: Everyone wants something slightly or even greatly different. So what to do? How about this: 1) We finalize the requirements document - including the ability for the most grandious systems - telemetry + every conceivable sensors + extra outputs. 2) We identify the minimum requriements - fuel control and spark control + pluse the minimum inputs to control these. 3) We design a small computer board that has the on-board processing capabilities to handle most, if not all the requirements determined in step (1). This board will have limited I/O though - just enough, maybe a little more, for step (2). The board will have connectors for a daughter or multimple daughter boards that will allow additional I/O. Programming this device would be easy. We can publish a document that basically says: At this memory address you'll find this info - and this is the address for injector control. If your just doing timing control you would simply not use those address... We can also reserve memory for look-up tables, telemetry etc. We may find that we will split up at this point into different project groups - but that's not bad - as long as we still exchang info. 4) We have discussions on algorithms, come up with programming aids or even programming routines. So what do you say? Can we come up with the most grandious requirements? My updated requirements list will be published latter today with, hopefully , everyones input already included. Dirk >From Diy_Efi-Owner Tue May 10 15:28:25 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA25023; Tue, 10 May 94 15:28:25 GMT Received: from localhost.eng.ohio-state.edu by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA25017; Tue, 10 May 94 11:28:24 -0400 @xxx.edu> To: DIY_EFI Subject: Re: crank sensors Date: Tue, 10 May 94 11:28:23 -0400 From: John S Gwynne Sender: Diy_Efi-Owner Precedence: bulk Reply-To: DIY_EFI | i think that drilling into the Harm. Bal. would be a mistake. I am not | sure, but i think this could damage the balancing of the H. B.? ? | | Perhaps, a better way of getting the timing down would be to use a | seperate plate bolted to the balancer's bolt containing the magnets to be | picked up with externally mounted sensor just like you speak of. Micro Switch (made by MG magnets?) makes what looks like a small socket head screw (rather: a screw with a magnet in the end) that could easily be placed in the harmonic balancer. I would want to use a horizontal mill to properly locate the holes, but if you hand selected four (V8) equally weighted magnets, I would not be concerned with the balance (IMHO). The last concern is how strong are they. I have not bought any yet, so I don't know for sure if it would handle high revs (the catalog I have doesn't give a spec. for this). I suspect it would. John S Gwynne @xxx.edu _______________________________________________________________________________ T h e O h i o - S t a t e U n i v e r s i t y ElectroScience Laboratory, 1320 Kinnear Road, Columbus, Ohio 43212, USA Telephone: (614) 292-7981 * Fax: (614) 292-7292 ------------------------------------------------------------------------------- ÿ