When you change the PID constants you leave the thermistor values alone. The only time you need to change the thermistor constants is if you use a different type of thermistor. Any 100K B3950K thermistor will use the same table values.
You can change the PID values for the hot end via M301, you just cannot do M303 autotune because the heating is not properly wired up in M303 to trigger the snapmaker specific heating routine. That could probably be fixed easily enough in the firmware.
More of a pain is the fact the bed PID has been disabled, and is only using bang-bang control. Itās worth recompiling the firmware to enable PID on both the hotend and also the bed. Maybe Iāll do that someday lol. Currently bricked the controller though need to hook a debugger up and reflash it.
He was mentioning on that thread that he was measuring the resistance on the thermistor at various temperatures and the tableās values were not lining up with the measurements if i recall, likely because of the airgap around the thermistor when they were building the table.
However, correcting that with a PID tune will not work. PID just affects the stability of the temperature, how much it oscillates, over, or undershoots. It does not affect gross differences like the table will affect, for example being off 30C in the reading.
For the PID to work as intended it must be fed correct readings from the A/D and raw->engineering units conversion, the latter of which is what the table is part of.
yeah badly worded. the thermistor values totally independent of the PID as peeps said. Two things being discussed at once and Im tired!. So yeah will try recompiling with a more representative thermistor table if i get chanceā¦ You can just use different temps like 230 for 205 etcā¦ just a problem when you want 250 for say Colorfabb XT / XTCF20 (with tungsten nozzle) but it wont get there!
Sure, XT is similar to PETG but its made from a proprietary polymer called Amphora. XT is Extra Tough compared to there NGEN which is also Amphora based. Have a look at their site and you can see all the material data sheets for impact resistance, strength etc.
XTCF20 is 20% chopped carbon fibre strands in the XT base material its very rigid but more challenging to print and requires hardend stee, ruby or tungsten nozzle to not wear out. Its likley it might wear the extruder gear too so im wary of printing much in it as the gear isnt easily replaceable
On the spare hotend with the printer, the thermistor wire is only long enough for the thermistor to just enter the hole that it is supposed to be in. If you do some gymnastics with the wiring harness yiu can get the thermistor all the way in the hole. Since the temperature differential may be quite high in both locations, where exactly is the thermistor supposed to be on a fully functional, correctly assembled hotend?
Hi guys, sorry to jump into the conversation. I believe this is the best place for my question. Iām not too sure where to put the thermal paste, correct me if Iām wrong but I would apply it on where I located the green circle. Thanks for your help.
