Hello

I modified ramps 1.4 board to use with arduino due as described in due + ramps mod

I can set on and off bed heater or extruder heater one at a time but not at the same time.
when I try second one to set on marlin drops both heaters instantly. Does not matter which one is switched first.

Activated bed PID, tuned extruder and bed PID values but it does not help.
no eeprom on board, so no ex-firmware parameter issue.
thermistors are working and assigned to correct heaters.
tried to extend thermal protection intervals-temperatures but none of tyhem helped.

To test if there is any hardware issues I wrote an arduino sketch and I able to switch on both heaters and read both thermistors. Mosfets are switched ok.
Power supply is sufficient, slight voltage drop from 12.15 V to 11.77 Volts when both heaters are working.

the error messages:
----------------------------------------------------------------------------
Error:Heating failed, system stopped! Heater_ID: 0
[ERROR] Error Heating failed, system stopped! Heater_ID: 0

Errorrinter halted. kill() called!
[ERROR] Error Printer halted. kill() called!
---------------------------------------------------------------------------

So I think there is a marlin config issue I am missing. Atached config files.
If you have any idea please post.

thanks

for experimenting only I switched off thermal protections.

Extruder and bed heaters are mutually exclusive.

RAMPS 1.4 pin D8 is connected to bed heater mosfet, D10 is connected to extruder heater mosfet.
When i switch on one the other goes off and vice versa..

So th eproblem is not in the thermal settings or protection.It is a logic issue in the code maybe... strange.

Make sure that the tabs on the RAMPS mosfets are not touching - that can cause all sorts of problems.