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Gen7 thermistors not working

Posted by hglaeser 
Gen7 thermistors not working
April 16, 2016 01:16AM
Hi

I'm so close to having my Gen7 2.0 complete and my printer working once again! Very exciting times. However both my thermistors are consistently reading 0, and not changing despite the hot end heating up very hot. I have checked for shorts and am pretty positive there aren't any. The thermistor is getting 3.3V as expected too. I may have missed something obvious in the config, but my old firmware had it set for an EPCOS 100k, as it is in Teacup. Any suggestions would be much appreciated smiling smiley
Re: Gen7 thermistors not working
April 16, 2016 11:04AM
Excellent opportunity to start a thermistor troubleshooting wiki page! See [www.reprap-diy.com]

Type of thermistor doesn't matter too much. They all work by the same principle, just their readings vary somewhat (which matters later).

What do these pins read on your Gen7?


Generation 7 Electronics Teacup Firmware RepRap DIY
     
Re: Gen7 thermistors not working
April 16, 2016 10:17PM
Wow, thanks for that! They're both reading 3.3V with no thermistor, and then dropping slightly with one installed (though quite insignificantly, but my multimeter is rubbish) and then down to very low readings when heated by a lighter. So seeing as the hardware is pretty much as expected, I had another look at the software and it turns out that one pin is working correctly, but the other is reading low. Say, 2.5 when the thermistor is warmed slightly and 1 otherwise. Whereas the other is reading approx 25 degrees at room temperature, which was the old behaviour.
Re: Gen7 thermistors not working
April 17, 2016 06:37AM
Quote
hglaeser
it turns out that one pin is working correctly, but the other is reading low. Say, 2.5 when the thermistor is warmed slightly and 1 otherwise. Whereas the other is reading approx 25 degrees at room temperature, which was the old behaviour.

D'oh, I just see that one commit [github.com] didn't make it to the master branch, yet. Some pins (one analog pin, but not the other) were shifted between the first prototype and the released Gen7.

Will fix this later today. Until then you can apply this commit manually or simply use the experimental branch: [github.com]


Generation 7 Electronics Teacup Firmware RepRap DIY
     
Re: Gen7 thermistors not working
April 19, 2016 06:17AM
Silence? Looks like it's working now. Fine. :-)


Generation 7 Electronics Teacup Firmware RepRap DIY
     
Re: Gen7 thermistors not working
April 19, 2016 07:55AM
Sorry, I haven't quite gotten around to updating the firmware. But the fix seems sensible and I'll try have a look at it tomorrow smiling smiley
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