repetier server fan values with decimals

I mount a laser true my fan pin
I would like to know if PWM values for fan accept values with decimals like 203.1345
if not is is more good to move laser true extruder ?
I think his values accept this kind of value

thank you.


  • edited January 2019
    nope, pwm values accepted are full numbers without decimals.

    Laser Mode also does not support PWM , its just on/off so you have to write the PWM laser driver yourself
  • I don't use it in laser mode , I just want to know if fan accept values with decimals like in example
  • edited January 2019
    no it doesnt. just full numbers 0...255
  • but if i set PDM instead of  PWM ?
  • nope. value is 8 Bit wide so only 0...255 possible
  • edited January 2019
    thank you
    can I change that value to make it float ?
    i would like to transform value in float but i don't know which files must be modified for this
    or which pin to use in repetier to have a large frequency for my laser
    I use arduino due radds 1.5
  • It is not possible. PWM is a integer value and you can only go full steps. There are only 256 intensities. With that resolution frequency is 15.25Hz. The value is not frequency it is intensity.

    In fact if you use laser you should use a laser driver and the default one only supports on or off. You can add own driver with PWM that can then use high frequencies. Firmware V2 also supports hardware PWM for laser output but requires a due based board.
  • edited January 2019
    I would like to know how can use my laser more efficient than PWM
    I use Repetier 1.04 firmware
    arduino due
    RADDS 1.5

    I activate in firmware laser module but i don't understand how to activate this in firmware, in repetier-server in repetier-host , how is working how I can produce a gcode for it and second, like you say got only on/off which cannot help me at all
    for me laser module in firmware is not necessary 

    I succeed using laser using fan2 pin wich is PWM 0 to 255 wich some programs like

    the problem is that program use values for laser intensity like M106 P1 S233.4524 with decimals wich is better but repetier cannot use decimals so it use only integer value from gcode

    ideea is between some values of pwm (example from 150 to 200 PWM) to obtain a big gama of grey  from white to black

    can be possible this using another pin from arduino and define it separate like a float number in repetier ?
    if yes, which pin and how can be accessed in gcode ?

    or any other solution ?
    or if I use extruder2 pin and using like a big value of impulses on mm can help my situation ?
  • The P and S parameter are always integer in repetier-firmware. That has to do how they get stored. Also you can not have a half cycle on or off. Fans use software PWM which is slow as I said. Also we store the value in a 8 bit variable so there it would get lost. As I said V2 has all this solved including gamma correction for laser and using hardware PWM. In V1 you need to write own driver for this or use motion speed to get different colors.
  • edited January 2019
    from my own experience...
    decimals are useless , you´ll  never get more than 10...12 shades of gray on f.e. pine wood.

    so if you have a start value of 150  there still are more than 100 steps left.

    the biggest problem when engraving is the color change of the material around the laser cut,
    which affects the next line.
    Also if you engrave wood the lignincoming out from the material  and laying down on surface affects the engraving.
    these problems need to be solved and for shure that things weight more than decimals.

    may be you should read some stuff from professional laser manufacturers .

    for example

  • thank you

    One more question please !!!

    I DON'T understand how to put machine from printer mode in laser mode !!!
    I don't find any information's about 

    in firmware is posible to put machine in laser or in printing mode
    after compile and upload the firmware must be a mode to switch to laser mode 
  • edited January 2019
    see repetier.ino there you can see all supported commands

    - M451 - Set printer mode to FFF
    - M452 - Set printer mode to laser
    - M453 - Set printer mode to CNC

    keep in mind you have to write a laser driver for pwm as there is just on/off implemented in firmware
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