My corexy hbot configurations and build pictures

Veti

@tracar said in My corexy hbot configurations and build pictures:

M305 P0 T100000 B4138 R4700 ; set thermistor + ADC parameters for heater 0
M305 P1 T100000 B4138 R4700 ; set thermistor + ADC parameters for heater 1

your thermistor settings are not configured properly. 4138 is the default and most likely wrong for your thermistors.

tracar

@Veti
this i had no clue i needed to fix. what do i need to do to fix this ?

Veti

@tracar

find out what thermistors you have and look in the spec sheet and find the beta value.

tracar

@Veti
ahhhh , i had to configer these in marlin as a 6 on the old prusa
i think that was a 100k

Veti

nearly all thermistors used today are 100k

marlin 6 is

6 : 100k EPCOS - Not as accurate as table 1 (created using a fluke thermocouple) (4.7k pullup)

not a good starting point.

where did you buy the thermistors?

tracar

@Veti
think it came with the prusa, i3 clone from folgertech a few tears ago!!

Veti

the prusa i3 clone comes with a mk8 hotend. are you still using that?

tracar

@Veti has been parted out long ago.
after reading up on this thermister stuff, i see what you are trying to get after.
i dont think i have the info, but can find out by using a temp probe . Or just ordering some from amazon that the values are known.

Veti

if you can establish the resistance at certain temperatures, then that would be perfect.

measure the resistance at something like 25, 120 and 240.

then use the https://configtool.reprapfirmware.org/Heaters click on the Beta value, select custom and enter those values.
It will calculate B and C for you. That would be more accurate as thermistors have variations that can lead to +/- 10 C.

Failing to do that you can buy a thermistor.
Preferable a Semitec 104-GT2.
I personally use a PT1000 (no daughter board necessary) for hotend and bed.

tracar

@Veti said in My corexy hbot configurations and build pictures:

f you can establish the resistance at certain temperatures, then that would be perfect.
measure the resistance at something like 25, 120 and 240.
then use the https://configtool.reprapfirmware.org/Heaters click on the Beta value, select custom and enter those values.
It will calculate B and C for you. That would be more accurate as thermistors have variations that can lead to +/- 10 C.
Failing to do that you can buy a thermistor.
Preferable a Semitec 104-GT2.
I personally use a PT1000 (no daughter board necessary) for hotend and bed

i understand, even with my current setup, i notice, its always overshooting the temp around 10 degrees, but then adjusts it to where it needs to be.

Veti

@tracar
that is an indication that you need to adjust the pid tuning.

see
https://duet3d.dozuki.com/Wiki/Tuning_the_heater_temperature_control

If during initial heating the temperature undershoots the target, reduce the A parameter. If it overshoots the target, increase the A parameter. Try increasing/decreasing it by 5% or 10%.

tracar

so 3724.2 would be a good starting point

tracar

@Veti said in My corexy hbot configurations and build pictures:

what about

M303 H1 S240 ; auto tune heater 1, default PWM, 240C target or maximum temperature

M303 ; report the auto-tune status or last result

Veti

yes and save those values in your config.g

tracar

the results of the M303 H1 S240

M307 H1 was used to get this info after the M303 H1 S240:

Heater 1 model: gain 869.9, time constant 308.4, dead time 3.1, max PWM 1.00, calibration voltage 24.2, mode PID, inverted no, frequency default
Computed PID parameters for setpoint change: P20.7, I0.672, D44.3
Computed PID parameters for load change: P20.

does it auto save this info? or how and where do i add this