C.ITOH CX-6000 plotter upgrade

New motors, grblHAL controller + Motöri the Plotter

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12 ohm Nema 23 motors replaced with Nema 17, original controller replaced with a STM32F446 grblHAL based controller with a HPGL plugin derived from Motöri the Plotter that makes grblHAL multilingual! At least it now has a basic understanding of HPGL, enough to plot KiCad schematics...

And no - this is not using a HPGL to GCode translator, the plugin bypasses the grblHAL GCode interpreter by activating a modified HPGL interpreter derived from Motöri the Plotter. The HPGL interpreter has been changed to use motion control etc. provided by grblHAL and can be switched in and out dynamically: $HPGL to enable, CTRL-X to exit back to the GCode interpreter.

After adding support for further HPGL commands and replacing the reed relay endstop sensors with real switches due to insane hysteresis it is now time to create a custom PCB and switch to a Pi Pico (RP2040) based grblHAL controller. This will bring the original front panel back to life enabling jogging, pen up/down etc...

JPEG Image - 300.43 kB - 02/09/2022 at 05:28


C_ITOH CX-6000

Pi Pico controller, KiCad v5 format

x-zip-compressed - 68.30 kB - 01/19/2022 at 17:43


  • New controller in place

    Terje Io02/07/2022 at 10:54 0 comments

    New controller is now in place after refactoring the Motori code and adding some HPGL commands including escape sequences for querying the input buffer size and free space. The escape sequences can be used by the app sending data to avoid overflowing the input buffer.

    I had an issue with the pen up/down font panel button creeping up on me that took some time to resolve, a tantalum capacitor on the front panel PCB had started leaking. It was used for deboucing the switch signal, but had the oppsite effect when leaking - it caused the signal to bounce in odd ways instead. After replacing all four tantals on the board the swiches now performs flawlessly, this includes the jog buttons.

    Remaining now is making some pen holders so that the pen change code can be verified.

    Original controller. There is a large heatsink on the underside of the plotter for the stepper driver transistors.

    The Pi Pico based controller in place, techonlogy has come a long way since the original was made!

  • Pi Pico controller PCB made

    Terje Io01/19/2022 at 18:01 0 comments

    Jogging and pen/up down from the original control panel works pretty well - but the code still needs a bit of polishing. There are reset in and out signals I have to figure out how to put to work - and the red alert LED should be lit on error conditions such as bad HPGL code received?

    Next up is a blanking plate for the big hole left where the serial and parallell ports were, now it will only be a small cutout for the micro USB. And I have to make some pen holders so that automatic pen selection can be verified.

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