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Hot end not heating past 160 degrees

Posted by gabemedina23 
Hot end not heating past 160 degrees
May 15, 2014 11:28PM
I built an Eventorbot for the second time. This time I am having a problem with the hot end not heating past 160 degrees. It actually did the first time I powered it up. I tried 2 power supplies, two resistors, the only thing that is different this time is the thermistor. I don't know if my firmware just doesn't mesh with the new thermister or what but I wouldn't know how to change that part
open | download - Sprinter_Eventorbot_18stepper.zip (104.7 KB)
open | download - ATH100K1R25.pdf (240.3 KB)
Re: Hot end not heating past 160 degrees
May 16, 2014 01:26AM
From running Marlin/createTemperatureLookupMarlin.py with a couple values from your table you can get some diagnostic values:

$ ./createTemperatureLookupMarlin.py --t1=25:100000 --t2=185:856.4 --t3=270:200.1
// Thermistor lookup table for Marlin
// ./createTemperatureLookupMarlin.py --rp=4700 --t1=25.0:100000.0 --t2=185.0:856.4 --t3=270.0:200.1 --num-temps=36
// Steinhart-Hart Coefficients: 0.000629002704724123, 0.000226616753500076,  7.60099986542248e-08 
//#define NUMTEMPS 36
const short temptable[NUMTEMPS][2] PROGMEM = {
   {(short)(15.49*OVERSAMPLENR), 350}, // v=0.0756456424736 r=72.1992151281 res=5.64467897524 C/count
   {(short)(17.32*OVERSAMPLENR), 340}, // v=0.0845710737641 r=80.8645700419 res=4.92276713582 C/count
   {(short)(19.43*OVERSAMPLENR), 330}, // v=0.0948677198007 r=90.9003585618 res=4.276524982 C/count
   {(short)(21.87*OVERSAMPLENR), 320}, // v=0.106789021511 r=102.572401499 res=3.70045069232 C/count
   {(short)(24.71*OVERSAMPLENR), 310}, // v=0.12064209193 r=116.207468842 res=3.18915603404 C/count
   {(short)(28.02*OVERSAMPLENR), 300}, // v=0.136800173996 r=132.209417828 res=2.7373961487 C/count
   {(short)(31.89*OVERSAMPLENR), 290}, // v=0.155718087522 r=151.080185789 res=2.34009660839 C/count
   {(short)(36.44*OVERSAMPLENR), 280}, // v=0.177951322051 r=173.447277184 res=1.99237749142 C/count
   {(short)(41.82*OVERSAMPLENR), 270}, // v=0.204179506541 r=200.1 res=1.68957429567 C/count
   {(short)(48.18*OVERSAMPLENR), 260}, // v=0.2352350059 r=232.03757774 res=1.42725557982 C/count
   {(short)(55.73*OVERSAMPLENR), 250}, // v=0.272137292221 r=270.533505834 res=1.20123729453 C/count
   {(short)(64.74*OVERSAMPLENR), 240}, // v=0.316133399978 r=317.222309425 res=1.00759383714 C/count
   {(short)(75.52*OVERSAMPLENR), 230}, // v=0.368744007623 r=374.21745606 res=0.842665934904 C/count
   {(short)(88.44*OVERSAMPLENR), 220}, // v=0.43181318803 r=444.272983413 res=0.703065532474 C/count
   {(short)(103.95*OVERSAMPLENR), 210}, // v=0.507557181992 r=531.007038264 res=0.585677933507 C/count
   {(short)(122.59*OVERSAMPLENR), 200}, // v=0.598603053216 r=639.213955053 res=0.487661525308 C/count
   {(short)(145.00*OVERSAMPLENR), 190}, // v=0.708001071005 r=775.304255377 res=0.406445507312 C/count
   {(short)(171.87*OVERSAMPLENR), 180}, // v=0.83918463437 r=947.931459329 res=0.339726157961 C/count
   {(short)(203.95*OVERSAMPLENR), 170}, // v=0.995838946903 r=1168.89480427 res=0.285462326495 C/count
   {(short)(242.00*OVERSAMPLENR), 160}, // v=1.18162735884 r=1454.45432085 res=0.241871051704 C/count
   {(short)(286.66*OVERSAMPLENR), 150}, // v=1.39971991317 r=1827.26994379 res=0.207424530024 C/count
   {(short)(338.35*OVERSAMPLENR), 140}, // v=1.65208663015 r=2319.29751576 res=0.180850147968 C/count
   {(short)(397.02*OVERSAMPLENR), 130}, // v=1.93857848851 r=2976.17262497 res=0.161136071368 C/count
   {(short)(462.02*OVERSAMPLENR), 120}, // v=2.25593658992 r=3863.94204073 res=0.147546137211 C/count
   {(short)(531.87*OVERSAMPLENR), 110}, // v=2.59702825166 r=5079.55734031 res=0.139649852957 C/count
   {(short)(604.31*OVERSAMPLENR), 100}, // v=2.95072992455 r=6767.49776006 res=0.137376755094 C/count
   {(short)(676.42*OVERSAMPLENR), 90}, // v=3.30282687383 r=9146.55438952 res=0.141110261543 C/count
   {(short)(745.06*OVERSAMPLENR), 80}, // v=3.63797927161 r=12553.7755925 res=0.151846405392 C/count
   {(short)(807.38*OVERSAMPLENR), 70}, // v=3.94229774058 r=17517.9727713 res=0.171461125146 C/count
   {(short)(861.32*OVERSAMPLENR), 60}, // v=4.20568459192 r=24885.2249131 res=0.203163270675 C/count
   {(short)(905.86*OVERSAMPLENR), 50}, // v=4.42314196157 r=36037.9258577 res=0.252273675991 C/count
   {(short)(941.00*OVERSAMPLENR), 40}, // v=4.59473108007 r=53286.1885386 res=0.327594276519 C/count
   {(short)(967.57*OVERSAMPLENR), 30}, // v=4.7244535433 r=80585.074181 res=0.443884023741 C/count
   {(short)(986.86*OVERSAMPLENR), 20}, // v=4.81865176694 r=124884.940553 res=0.626505023167 C/count
   {(short)(1000.34*OVERSAMPLENR), 10}, // v=4.88449189801 r=198748.932119 res=0.920575305287 C/count
   {(short)(1009.43*OVERSAMPLENR), 0}  // v=4.92885010555 r=325588.613651 res=1.41024287731 C/count

From the 160C line, you should expect your thermistor to measure about 1454 ohms, and with a 4700 ohm resistor pulling up to 5V, you should see about 1.181V across the thermistor. If you measure something different when you firmware is reporting 160C, then you aren't using a good table for this thermistor. You could fit this one into Marlin's thermistortables.h if you alter the array definition line to something like the below and then in Configuration.h #define TEMP_SENSOR_1 99 to use it. Or you could adjust it for Sprinter and #define OVERSAMPLENR 1.

const short temptable_99[][2] PROGMEM = {

Edited 3 time(s). Last edit at 05/16/2014 01:32AM by DaveX.
Re: Hot end not heating past 160 degrees
May 18, 2014 02:08PM
Thank you so much for the temp table, I got it to work. The temp now stops at 168 deg... So it's a better reading but I can't get over that hump.

Edited 1 time(s). Last edit at 05/18/2014 02:09PM by gabemedina23.
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