M42 Command Problem - All ports switching simultanously

  • Hi,
    I'm using on the Duex5 all heaters with M307 H2 A-1 C-1 D-1 to steer valves etc. (incl. flyback diodes). After running M307 the P2 - P7 are available. Then the strange things happens. Whatever M42 command I prompt (M42 P2 S255, M42 P3 S255,...) all heater outputs come on and off together. Did I miss something?

    Cheerz for any input.

  • administrators

    Check whether you have any M307 commands in config-override.g.

  • Not working with conifg-overwrite.g file yet, so there is no such file. Sent commands via YAT directly. Planned is to code it directly into config.g file as soon as it will work.

  • administrators

    Are you saying that M42 P2 S255 is turning all of H2-H7 on? If so, how have you connected the valves and the flyback diodes to the DueX5? If you connect just one of them to the DueX5, do the heater LEDs indicate that any others are turning on?

  • The valves are connected with a common ground (24V). Here the schematics and a picture. When I send the command M42 P2 S255 all onboard LED are going on and the valves are acting.2_1554291743417_thumbnail_IMG_20190403_133245.jpg 1_1554291743417_thumbnail_IMG_20190403_133239.jpg 0_1554291743417_thumbnail_IMG_20190403_133148.jpg

  • administrators

    You can't use a common ground, because the VIN side is already common to all outputs. Also your flyback diodes are not connected correctly. if you don't fix that, the heater mosfets will start to fail.

  • so you are switching the "minus" on the board, correct? we bridged it because we do have a valve isle with a common ground. now the lucky thing is, that the valves mounted are in a "unpolar" execution, so we can wire it that it will be correct... don't worry about the diodes shown in schematics, already mounted them the correct way 😉


  • Working pefect! Definetly solved! Thanks

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