Peter Gregson

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  • in reply to: What is pin 1 on the DB25 connector used for? #19003
    Peter Gregson
    Participant

    Hello Brian,

    Thank you for your prompt answer. It is helpful.

    Just a couple of clarifications, please, as follows:

    1. I appear to have a Rev 1 board. Is there any way that I can run a jumper to some part of the HobbyCNC Pro 4 circuit from this pin so as to gain the Enable-pin function?

    2. Is the Enable pin on the Rev 2 board an input or an output?

    3. I like to provide isolation between different power domains whenever possible. My concern here is that I would like to limit the damage if, for some reason, one of the SLA7078MR chips were to fail. By using optoisolators, I limit the damage to the HobbyCNC Pro 4 in that eventuality and protect the controller board from damage. Since my controller board requires me to make an adapter card, this would be an opportunity to put optoisolators on all signals to/from the HobbyCNC Pro 4 as well as on all limit-switch, home switch and tool touch-off points.

    4. How much power, if any, can I draw from the +5VDC pad? I could mount a heatsink on the LM317. Would it be preferable to use a separate regulator for my adapter card?
    Thanks for your help.

    Best regards,

    Peter

    in reply to: Timing requirements for driving HobbyCNC Pro 4 #18994
    Peter Gregson
    Participant

    Thanks Brian. Your response is most helpful. The Arduino site has lots of useful timing information. Also, from a preliminary review of thee Sanken SLA7078MPRT data sheet, it appears that you are right and that the inputs can be 3.3 volts.

    Is there any chance of getting a schematic for the HobbyCNC Pro 4? I’m an electrical and electronic engineer and I would like to better understand the design of the board.

    Best regards,

    Peter

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