On 6/6/2012 6:01 AM, andy pugh wrote: > On 4 June 2012 19:18, Dave<e...@dc9.tzo.com> wrote: > > >> 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 >> > As an alternative (though probably more expensive than most home > FDN-ers would like to pay) is this $20 chip which does all the work > then talks SPI. > http://uk.rs-online.com/web/p/temperature-sensor/6987118/ > LinuxCNC can talk SPI through Mesa cards. > >
Still, that seems like a lot considering I can buy something like this (and this is not the cheapest available) for $60 complete with a display and Modbus interface. http://www.automationdirect.com/adc/Shopping/Catalog/Process_Control_-a-_Measurement/Temperature_-z-_Process_Controllers/1-z-16_DIN_Size_%28SL4848_Series%29/SL4848-CV I found some links to Chinese suppliers who have controllers closer to $30, but of course you have to ship them from China. Doing effective analog temp control on the cheap (actually dirt cheap level) is difficult when dealing with higher temperatures. 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
