I think the thermistor tables and generator script should be changed as per http://www.brokentoaster.com/blog/?p=148
A few issues: DaveX 18:22, 6 November 2012 (UTC)
- The links to http://svn.reprap.org/trunk/reprap/firmware/Arduino/utilities/createTemperatureLookup.py appear broken.
- https://github.com/reprap/firmware/blob/master/createTemperatureLookup.py appears to be the official program
- http://reprap.svn.sourceforge.net/viewvc/reprap/trunk/reprap/firmware/Arduino/utilities/createTemperatureLookup.py?view=markup&pathrev=3448 by Nophead calculates its own max_adc and treats r1=0 as a non-existent or r=infinity
- https://github.com/triffid/Teacup_Firmware/blob/master/createTemperatureLookup.py is used by teacup, but does the temps as temp*4 for fixed point math.
- R1 of zero seems nonsensical with respect to the text. The article needs a schematic and the matching code to make sense of it.
I agree that r1=0 seems nonsensical. Is there a better way to indicate we're only using one resistor (R2), and there is nothing there at the position marked "R1" on the schematic? Would tweaking the Python code so it prints "r1=None" or "r1=+INF" in that situation help? --DavidCary (talk) 07:20, 4 March 2014 (PST)
The code at http://reprap.svn.sourceforge.net/viewvc/reprap/trunk/reprap/firmware/Arduino/utilities/createTemperatureLookup.py?view=markup&pathrev=3448 indicates a --num-temps=... option, but it is not in the code. The following patch adds it:
- createTemperatureLookupNophead.orig.py 2012-11-07 15:39:35.000000000 -0500 +++ createTemperatureLookupNophead.py 2012-11-07 15:38:03.000000000 -0500 @@ -66,7 +66,7 @@ num_temps = int(20); try: - opts, args = getopt.getopt(argv, "h", ["help", "r0=", "t0=", "beta=", "r1=", "r2="]) + opts, args = getopt.getopt(argv, "h", ["help", "r0=", "t0=", "beta=", "r1=", "r2=", "num-temps="]) except getopt.GetoptError: usage() sys.exit(2) @@ -85,6 +85,8 @@ r1 = int(arg) elif opt == "--r2": r2 = int(arg) + elif opt == "--num-temps": + num_temps = int(arg) if r1: max_adc = int(1023 * r1 / (r1 + r2)); @@ -124,4 +126,4 @@ print __doc__ if __name__ == "__main__": - main(sys.argv[1:]) \ No newline at end of file + main(sys.argv[1:])
supplier part number
I'm thinking about deleting all the supplier part numbers from this page, keeping manufacturer part numbers.
Does anyone find the supplier part number useful? In any situation that I could possibly use the supplier part number, wouldn't the manufacturer part number work just as well? --DavidCary (talk) 07:20, 4 March 2014 (PST)
Does anyone ever use the Rz value?
The firmware never uses Rz -- it has a lookup table of R vs T at many points (typically *not* including a point at 0 °C) and uses linear interpolation.
The Python script that generates that lookup table never uses Rz -- it calculates that lookup table from a command line something like
- ./createTemperatureLookup.py --r0=100000 --t0=25 --r1=0 --r2=4700 --beta=4066 --max-adc=1023
-- none of those input values are equal to Rz or derived from Rz, right?
- Some folks outside of standard reprap might, like IceRap or http://www.3ders.org/articles/20120103-3d-ice-printer.html , and Rz could be on the specs of some thermistors. Pt-100 and Pt-1000 spec the Rz as part of their names. Also, Nophead's new script from http://hydraraptor.blogspot.com/2012/11/more-accurate-thermistor-tables.html and the Marlin script at https://github.com/ErikZalm/Marlin/blob/Marlin_v1/Marlin/createTemperatureLookupMarlin.py can both use the Rz if that is part of the range of interest. DaveX (talk) 06:57, 11 June 2014 (PDT)