Heatbed Thermal Runaway
Hello everyone,
I have a rework of prusa and try to use prusa mk2 firmware.
All tests with PLA were done successfully because the temperature for heatbed is 55º, but the problem is when I try to print with ABS because I get THERMAL RUNAWAY ERROR.
I have verified the following:
If you preheat the HOTEND to 255º, the current is 12v and it rises to 255º without problem.
If you preheat the HEATBED to 90º, the current is 12v and it rises to 90º without problem.
But when I try to preheat the HOTEND and HEATBED at the same time, the HEATBED current is 4.75V.
I compiled and flashed my 1.4 ramp with my old marlin version and can preheat the HOTEND and HEATBED simultaneously with 12V in HEATBED and HOTEND and I can print with ABS without problems.
Any idea??
Thanks and regards.
Re: Heatbed Thermal Runaway
For this, I think you will need to contact your hardware provider.
Peter
Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…
Re: Heatbed Thermal Runaway
I thinnk that is a firmware or configuration problem because with marlin firmware I can print successfully with al materials and temperatures.
Re: Heatbed Thermal Runaway
Printers on this forum generally use Mini Rambo controllers, not Ramps 1.4
did you get the Ramps 1.4 from Prusa Research?
to the best of my knowledge the Original Prusa i3 software will not work on a Ramps unless it is significantly modified. which is not supported by Prusa...
regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
Re: Heatbed Thermal Runaway
Yes, I know. I modified the firmware for use the prusa mk2 firmware because the menu, options and settings are better than marlin.
Re: Heatbed Thermal Runaway
Hi Damian the reason Prusa Research specified the Mini Rambo, is because it is better suited to working with their software and hardware solution, than the Ramps board.
as the raw marlin works with RAMPS, the prusa research firmware works with the prusa research hardware...
maybe you overlooked some differences and didn't cater for them in your re-purposed version of the firmware.
other people have used ramps, perhaps if you use the search function on the forum. you can benefit from other people's efforts.
Best wishes, Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
Re: Heatbed Thermal Runaway
Hi everyone,
I detected the difference between the Marlin firmware and the Prusa mk2 firmware that decrease the heat current from 12V to 4.35V when it simultaneously preheats the heatbed and the hotend.
When the temperature of Hotend> 50 °, the heat current decreases. I increase the number from 50 to 120 ° of the variable EXTRUDER_AUTO_FAN_TEMPERATURE, when I repeat the preheating, the current decreases when the temperatuure of hotend > 120 °
This is the prusa code of the file 1_75mm_MK2-RAMBo13a-E3Dv6full
#define EXTRUDER_0_AUTO_FAN_PIN 8
#define EXTRUDER_1_AUTO_FAN_PIN -1
#define EXTRUDER_2_AUTO_FAN_PIN -1
#define EXTRUDER_AUTO_FAN_TEMPERATURE 50
#define EXTRUDER_AUTO_FAN_SPEED 255 // == full speed
If I compare the code of the configuration of Marlin, for default the value of EXTRUDER_0_AUTO_FAN_PIN is -1.
#define E0_AUTO_FAN_PIN -1
#define E1_AUTO_FAN_PIN -1
#define E2_AUTO_FAN_PIN -1
#define E3_AUTO_FAN_PIN -1
#define EXTRUDER_AUTO_FAN_TEMPERATURE 50
#define EXTRUDER_AUTO_FAN_SPEED 255 // == full speed
I modified the code of prusa mk2 and I can print without porblem
#define EXTRUDER_0_AUTO_FAN_PIN -1
Can you tell me what is the propouse of this variable??
Thanks and regards.
Re: Heatbed Thermal Runaway
EXTRUDER_0_AUTO_FAN_PIN is the pin that the extruder cooling fan is connected to - it's -1 in marlin because it's not enabled by default, but it is in prusa firmware.
Re: Heatbed Thermal Runaway
Working prusa firmware for RAMPS and compatible boards is at https://github.com/slippyr4/Prusa-Firmware