At 04:55 PM 9/30/2009, Tony Vandiver wrote: >Is there a down and dirty way to measure thermocouples reliably even >when they are not isolated? Not really. Nowadays, I pretty much insist on isolated thermocouples. They can be priced reasonably if you work with the manufacturer and you are buying in at least hundred lot quantities. One approach I tried in years gone by was to use an isolated dc-dc convertor and an opto-isolator: the thermocouple reading was digitized, then sent over the opto-isolator. It worked but its not cheap. Figure on at least 10 bucks extra cost per isolated channel. dwayne -- Dwayne Reid Trinity Electronics Systems Ltd Edmonton, AB, CANADA (780) 489-3199 voice (780) 487-6397 fax www.trinity-electronics.com Custom Electronics Design and Manufacturing -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist