On 6/4/2012 1:51 PM, Jeshua Lacock wrote: > On Jun 4, 2012, at 7:14 AM, Stephen Dubovsky wrote: > > >> On Mon, Jun 4, 2012 at 8:52 AM, Dave<e...@dc9.tzo.com> wrote: >> >> >>> If anyone has a cheap way to do effective - accurate temperature >>> measurement - on the cheap, I'd like to know about it. :-) >>> >>> >> cheap=thermistors. Who cares they are non-linear if you're using a digital >> controller? ;) Linearize them in the controller. We use a $0.10 >> thermistor in production that we can easily get to within +-1C from -40C to >> +80C using a processor (thats the range we're after). The beta tolerance >> of the thermistor at the ends is a bigger factor than the linearization >> table/equation. Obviously an extruder will need a higher temp but that >> just requires changing the biasing resistor. >> > This is just what I read on the MakerBot website, but they claim that > thermocouples are really required above 150C - which is the temperature range > being using. > > > Best, > > Jeshua Lacock > Founder/Engineer > 3DTOPO Incorporated > <http://3DTOPO.com> > Phone: 208.462.4171 > > >
Makes sense. Thermocouples are the standard on all of the commercial plastic extruders I have worked on. By the time you do linearization of a TC and cold junction compensation, you might was well buy a cheap PID controller and interface to that. If you were going to sell 100 of them, ok, but for a one off... there are easier ways. I notice that Mesa has some PC104 cards that can do TCs. Dave ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
