Part cooling fan

I am using ramps 1.4 set to operate two extruders and I wish to incorporate a part cooling fan in repertier..
I have also bought the RRD fan extender.   Would somebody be gentle enough to explain to me what needs to be changed in the firmware to be able to activate the fan via machine code in the program.  There is a lot of instructions over the internet but in repertier its a bit scant.  Hope it can be done.
Many thanks in advance.


  • Just enable fan in config tool and set fan pin to the digital pin number of the extender where it is connected. Do nit use the default symbolic fan identifier.
  • I am sorry but I can`t fully understand.  
    I need to only change the firmware file configration.h or need to change the Pins file as well?

    #define FAN_PIN 4    was -1
    trying to control Via pronterface
    now I can command M106 without getting unknown command returned but still my fan won`t start.
    can somebody give me a step by step instruct how to go about it please?
    Thanks all....

    #undef FAN_PIN
    #define FAN_PIN 4
    #undef FAN_BOARD_PIN
    #define BOARD_FAN_SPEED 255
    #define BOARD_FAN_MIN_SPEED 0
    #define FAN_THERMO_PIN -1
    #define FAN_THERMO_MIN_PWM 128
    #define FAN_THERMO_MAX_PWM 255
    #define FAN_THERMO_MIN_TEMP 45
    #define FAN_THERMO_MAX_TEMP 60
    #undef Z_MIN_PIN
    #define Z_MIN_PIN -1

  • Yes, that is exactly ho it is supposed to work. My extender had pins 4 and 5 so make sure you used the right one. Also the extender needs 12v input to work, so make sure you also have that wire.
  • Hi Repetier, Thanks for your input,
    however I do not understand- your extender had pins 4 & 5.....  what are you refering to?
    Did you alter anything in the Pins file?

     I am taking the 12 V input link from the ramps pins which power the fan.  There are two pins next to the diode and are used for powering the extruder fan- is this correct? or do I need to connect directly to 12V?

    Also, next to the reset switch I have a jumper and I have noticed many boards do not have it.
    i am supposed that with M106 S255, I should run one fan and with M42 P11 S255 should power the other fan, but nothing runs...:-(   any help appreciated.

  • My extender had 2 fan outputs on pin 4 and 5. These pins are only 5v 20mA so a mosfet needs to convert this to 12v signal. So the extender needs 12v always on as input so you get 12v on the outlets when turned on. If not no power.

    your M42 example was for pin 11. using M42 on a fan pin will not work as the fan control we directly disable it. You should compare where you out the extender on and ramps pin layout to see whcih pin numbers are possible. Maybe you are using a different extender or pace to connect it to.
  • After so much trials, managed to operate the ramps fan extender on one channel only..

    #undef FAN_PIN
    #define FAN_PIN 11
    #undef FAN2_PIN
    #define FAN2_PIN 6

    With M106 S255, fan runs and M107 stops
    I have swapped the Fan_PIn and Fan2_pin  and noticed that the fan runs on the other terminal.
    I deducted that the pin 11 is correct.
    You have said that M42 P11 S255 does not start the other fan,
    so what is the correct command for making this run?
    I tried command S126 in ponterface and it says unkown command...
    any lead appreciated.

  • In M106/M107 you can set fan number with P so nothing or P0 is fan 1 and P1 is fan 2.
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