I've never heard of a Copper RTD. While Copper has quite a high tempco of resistance, I think it is much more difficult to get a very accurate value for it than it is for Platinum so most metal-based RTDs use Platinum. On Mon, Sep 11, 2017 at 1:54 PM, William Couture wrote= : > I ran into this sensor when I bought a cheap Chinese controller -- it cam= e > with one. > > I write software for industrial process controllers professionally, and > occasionally buy > one of the cheap controllers I see around (aliexpress, ebay) just to see > how they are > built and how capable they are. > > I'd never heard of a CU-50 RTD, and couldn't find anything except the one > image I > linked to. > > I though one of you might provide more insight. > > Bill > > On Sat, Sep 9, 2017 at 6:41 PM, wrote: > > > Quoting William Couture : > > > > > Both those charts have different thermal coefficients, and have > different > > > "zero" scales -- the 10R is 10R at 25C, the 100R is 100R at 0C. > > > > > > the 10R chart multiplied by 5.5356 is closer, but it's strange that a > > real > > > chart can't be found anywhere... > > > > > > Bill > > > > They're all real- it's just that there is no international standard > > for Cu RTDs that I know of. You have not mentioned why you want this- > > obviously if you are buying the sensor you are going to want to go to > > the manufacturer for the data. If you are trying to make a general > > purpose indicator or controller.. you might want to use this (assuming > > the reference temperature of 25 C is appropriate..) > > > > http://www.pyromation.com/Downloads/Data/427_c.pdf > > > > Again, scale the numbers appropriately (5:1 in this case). Anything > that's > > within a degree or two C at the extremes is probably better than the > sensor > > interchangeability. > > > > Where exactly did you run into a 50 ohm copper RTD? > > > > --sp > > > > > > > > On Fri, Sep 8, 2017 at 10:15 PM, wrote: > > > > > >> Quoting William Couture : > > >> > > >> > Or possibly [OT] -- maybe I'm searching with the correct terms, bu= t > > I'm > > >> > trying to find > > >> > an resistance chart for a CU-50 RTD probe. > > >> > > > >> > The best I've been able to come up with is this image, which isn't > > quite > > >> > readable: > > >> > > > >> > https://is.alicdn.com/img/pb/747/046/531/531046747_904.jpg > > >> > > > >> > Pointers to something better? > > >> > > > >> > Thanks! > > >> > Bill > > >> > > > >> > > >> http://www.thermometricscorp.com/PDFs/10_ohm_copper_rtd-0. > > 00427_in_C.PDF > > >> > > >> Multiply numbers by 5. > > >> > > >> OR > > >> > > >> http://www.thermometricscorp.com/images/Accessories/ > > >> thermometricscorp_2129_12162627.gif > > >> > > >> Halve these numbers. > > >> > > >> depending on whether it's 50R at 0 degrees C or at 25 degrees C. > > >> > > >> There may be others based on 75F or something. > > >> > > >> Copper RTDs are all over place in terms of the quoted resistance (an= d > > >> therefore the tempco) when you get down to the last decimal place or > > >> two, AFAIK there is no standard. > > >> > > >> One of the main applications would be homemade with a bit of wire le= ft > > over > > >> from winding the motor, so annealing and exact composition would be > > >> questionable. > > >> > > >> --sp > > >> > > >> > > >> > > >> > > >> > > >> > > >> > > >> -- > > >> http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive > > >> View/change your membership options at > > >> http://mailman.mit.edu/mailman/listinfo/piclist > > >> > > > > > > > > > > > > -- > > > Psst... Hey, you... Buddy... Want a kitten? > > straycatblues.petfinder.org > > > -- > > > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive > > > View/change your membership options at > > > http://mailman.mit.edu/mailman/listinfo/piclist > > > > > > > > > > > -- > > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive > > View/change your membership options at > > http://mailman.mit.edu/mailman/listinfo/piclist > > > > > > -- > Psst... Hey, you... Buddy... Want a kitten? straycatblues.petfinder.or= g > -- > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .