Laser and servo needs to have different modes



  • Hello

    As many others I have experienced the servo keeps getting to hot and getting burnt.

    Probable cause, the servo is being "overdriven". Not in applied voltage but in to frequent updates.
    A standard servo will expect an update frequency of about 50 Hz.
    The laser being driven by the same output will need continous pulses to keep the laser on at all times.

    With the servo pulses defined as 1-2mS, getting 100% duty rate for the laser means around 500Hz.
    That is 10 times the number of pulses that the servo expect, which causes it to overheat!

    This will require the firmware to have a laser/servo switch, that limits the output to the servo.

    Regards


  • Developer of T2Laser Software

    @offroad You cannot drive the servo correctly using the laser PWM signal (which is either 1kHz or 7.8kHz), you are supposed to change the firmware setting to servo mode then it will output the correct signal. As long as you don't drive it into limits it will be fine.

    0_1502191989397_upload-7d72c27e-0f6f-41e9-94fc-0871ae3509a5



  • @zax Thanks for your reply. I have seen the laser mode mentioned in the grbl 1.1 documentation, but I wasn't aware that it affected the pwm output in that way ?
    Or are you talking about something else entirely ?

    The software provided with the EleksDraw don't seem to have any options for it.
    Will the T2Laser software work on a Mac ?

    I do have a Windows machine that I can use to drive the laser but I'd prefer to use the Mac.

    Am I correct in assuming that switching between the modes are a simple command to grbl or is it actually reflashing a different grbl setup?


  • Developer of T2Laser Software

    @offroad I haven't used their software but you can still use this feature as it's available in their firmware. Laser mode does not switch to servo, that is for CNC spindle or laser.

    T2Laser will only work on a Mac using a virtual machine, it has been tested with most of the options (free and paid). The trial is free so you can test it.

    There are other benefits with T2Laser for the EleksDraw, you can send sequential colors and the machine will pause and tell you to change pens for multi-color drawings or you can send individual colors 1 by 1 etc.

    Other features include optimization of the output which can significantly reduce the time (usually 30% or more), centerline and manual tracing and so much more.

    https://www.dropbox.com/s/ufcobnot8653na4/T2Laser_Intro5.pdf?dl=1



  • @Zax I think I have this sorted now.

    I didn't have the "Mana SE" firmware installed and getting that was a "pain in the..."
    I had to try several versions of Avrdude before finding one that worked and actually managed to flash the Nano.

    And the documentation for EleksDraw doesn't really help. It took me a while to find the mention of E2/A1/A0 switches in the software. Without your response I doubt that I would have found it.... Thanks again !


  • Developer of T2Laser Software

    @offroad Glad to help.

    I published assembly guides for several of these systems with step by step pictures, and although the firmware loading and setup uses T2Laser it can be done with the free trial version and is probably a lot easier than AVRDude or EleksCAM. You can then use any software to run the machine.


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