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  • Question about electronics terminology for you learned folk.

    My CNC controller board has 5V & 12V outputs in addition to all the normal magic signals. The manual says:

    "On board power supply supplies the following:
    Stabilised +5V output at 500mA (not to be used for machine I/O).
    Stabilised ±12V outputs at 200mA (not to be used for machine I/O)."

    What does "machine I/O" mean? I wanted to use the 5V supply for a separate spindle speed sensor board and 12V for the B.O.B. Would that be safe in light of the "machine I/O" admonition?

    Should I have looked it up in HTRAL before posting?
    Milton

    "Accuracy is the sum total of your compensating mistakes."

    "The thing I hate about an argument is that it always interrupts a discussion." G. K. Chesterton

  • #2
    Originally posted by DICKEYBIRD

    Should I have looked it up in HTRAL before posting?
    Not if you display your towel prominently other readers will assume that you not only have read HTRAL but have a copy with you at all times they will also automatically assume that you are also in possession of a toothbrush, washcloth, soap, tin of biscuits, flask, compass, map, ball of string, gnat spray, wet-weather gear, space suit etc.

    Comment


    • #3
      Originally posted by DICKEYBIRD
      My CNC controller board has 5V & 12V outputs in addition to all the normal magic signals. The manual says:

      "On board power supply supplies the following:
      Stabilised +5V output at 500mA (not to be used for machine I/O).
      Stabilised ±12V outputs at 200mA (not to be used for machine I/O)."

      What does "machine I/O" mean? I wanted to use the 5V supply for a separate spindle speed sensor board and 12V for the B.O.B. Would that be safe in light of the "machine I/O" admonition?

      Should I have looked it up in HTRAL before posting?
      Might be due to the low current rating? They dont want you using it to power high current drawing "appliances"? JR
      My old yahoo group. Bridgeport Mill Group

      https://groups.yahoo.com/neo/groups/...port_mill/info

      Comment


      • #4
        Originally posted by DICKEYBIRD
        What does "machine I/O" mean? I wanted to use the 5V supply for a separate spindle speed sensor board and 12V for the B.O.B. Would that be safe in light of the "machine I/O" admonition?
        Machine I/O, Input/Outputs, In light of the 500ma limit, I suspect they may think it will be overloaded if using it for contactors/relays etc?
        Take it off of a HD connector in the PC supply.
        Max.

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        • #5
          Well, why else are they providing those outputs? I agree with the low current observations; that is not a whole lot of juice, but sufficient for a number of sensors and encoders. Also, watch for ground loops.

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          • #6
            They are just assuming that most users won't have a clue, and they don't know what machine IO will be in use. I'm sure you can use the power for selected low current operations, if you take care to isolate from other power accidental or not (safety), be cautious of ground loops, inductive loads, and.... and....
            Last edited by lakeside53; 05-03-2012, 11:55 AM.

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            • #7
              The problem is that if it is already assigned to powering the controller board, what is it already drawing in the way of current?
              Max.

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              • #8
                Assuming this is a SmartStep board (?) the manual goes on to say:-

                "These voltages are provided for use with external equipment such as joysticks, analogue input amps or pots."

                and

                "The outputs should only be used for circuitry local to SmartStep/3 such as a potentiometer on the
                front panel. Additional filtering will be required if the cables are run outside the unit both for
                emissions and immunity
                ."

                Cheers

                .
                Last edited by Barrington; 05-03-2012, 12:18 PM.

                Comment


                • #9
                  Barrington, you should get a prize; yes it's a SmartStep/3 board. You either have a good memory or I've asked so many questions about this stuff it's burned into your memory whether you want it to be or not.

                  It just looked like an easy way to reduce the number of devices in the control box but I think I better source the power elsewhere to be on the safe side.

                  Thanks for all the comments.
                  Milton

                  "Accuracy is the sum total of your compensating mistakes."

                  "The thing I hate about an argument is that it always interrupts a discussion." G. K. Chesterton

                  Comment

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