Some useful info about the Hotend cooling fan and RUMBA.
Just thought I would share this, it may already be in the forum somewhere so if it is sorry.
It bugged me that I had to have my hotend cooling fan running all the time while the printer was powered on, even when the hotend heat was turned off. I started to do some searching and found a way to have the hotend cooling fan only come on when the hotend is above a certain temp.
You need to edit the Configuration_adv.h file and change a setting in it. Below is the area you want to change and what you want to change it to. These changes will control the Hotend cooling fan with the Fan 1 output on the RUMBA.
This is the original setup.
Code:
// Extruder cooling fans
// Configure fan pin outputs to automatically turn on/off when the associated
// extruder temperature is above/below EXTRUDER_AUTO_FAN_TEMPERATURE.
// Multiple extruders can be assigned to the same pin in which case
// the fan will turn on when any selected extruder is above the threshold.
#define EXTRUDER_0_AUTO_FAN_PIN -1
#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
This is the modified setup.
Code:
// Extruder cooling fans
// Configure fan pin outputs to automatically turn on/off when the associated
// extruder temperature is above/below EXTRUDER_AUTO_FAN_TEMPERATURE.
// Multiple extruders can be assigned to the same pin in which case
// the fan will turn on when any selected extruder is above the threshold.
#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
The change is changing the -1 to 8 in the #define EXTRUDER_0_AUTO_FAN_PIN line. Pin 8 is the output for Fan 1. So this will turn on your hotend cooling fan anytime the extruder temp is above 50 and will turn it off when the hotend temp drops below 50. When you make the change be sure you don't leave the - in front of the 8 otherwise it will ignore it.
One word of caution if for some reason your thermocouple comes unplugged or malfunctions your fan may not turn on. You would have some other problems if this happened anyway I guess.
Be sure you test this after you make the changes to the FW and upload them so you don't melt your extruder base.
Thanks,
Chadd
