Quoting alan smith : > Decided not to hijack the threads...start a new one. > > So this new client of mine, dealing with RTD's....are they just so > much more accurate than any other type of temp sensors? He wants > to read once a minute. Then make sure it didnt hit a threshold, > and if it does, turn on an alarm. Its not a temperature controlled > process or anything like that, just simply making sure its staying > within limits. Industry standard is to use RTD's but I'm just > curious if there isnt anything just "as good" ? As with most engineering questions.. it depends. RTDs are extremely accurate and stable devices. They can be a bit slow (time constant in air with appropriate protection might be many seconds), and may not be the cheapest. They are not good for very high temperatures (over some hundreds of degrees C), or (unless you get into exotic materials rather than plain old Platinum) at extreme low (cryogenic) temperatures. They are relatively fragile compared to thermocouples. They are high level devices, fairly linear, and are not too demanding of the measuring circuitry, compared to thermocouples. Best regards, Spehro Pefhany -- "it's the network..." "The Journey is the reward" s...@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist