Charge pump

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Thread: Charge pump

  1. #1
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    Default Charge pump

    Dear all,
    I am building my first milling machine, using UC300ETH and UCBB. I have read a lot of posts about the charge pump, but it is not clear if I need it or if it is useless.
    Can you help me?

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    Default Re: Charge pump

    Charge pump is a PWM pulse train. You can use an external electronics to sense the pulses and that electronics can switch an output on if the pulses are OK and off if the pulses are missing.
    You can use that circuit to switch things off in your control box if the pulses are missing because the connection is broken between the PC and the motion controller.
    You can use an enable signal too instead of a charge pump. The UC controller will switch that off too if it looses the connection for example if the PC freeze.



  3. #3
    Community Moderator Al_The_Man's Avatar
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    Default Re: Charge pump

    The idea of the watch-dog timer/Charge-pump is to enable the E-stop circuit, if Mach or the PC crashes or shuts down for any reason the E-stop becomes active and shuts off external power to motors. both servo and spindle etc.
    Al.

    CNC, Mechatronics Integration and Custom Machine Design

    “Logic will get you from A to B. Imagination will take you everywhere.”
    Albert E.


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    Default Re: Charge pump

    Quote Originally Posted by Al_The_Man View Post
    The idea of the watch-dog timer/Charge-pump is to enable the E-stop circuit, if Mach or the PC crashes or shuts down for any reason the E-stop becomes active and shuts off external power to motors. both servo and spindle etc.
    Al.
    Yes but if mach crashes there is already an external motion controller to handle it. Charge pump was only important with the printer port, but not really when using a motion controller which handles the PC crash event.



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    Community Moderator ger21's Avatar
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    Default Re: Charge pump

    Charge pump was only important with the printer port
    The charge pump is still useful, to prevent powering up the machine until the software is running, and killing power when the software closes.

    Gerry

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    Default Re: Charge pump

    The charge pump is still useful, to prevent powering up the machine until the software is running, and killing power when the software closes.
    An enable signal can do the same.



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    Gold Member john-100's Avatar
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    Default Re: Charge pump

    when a PC crashes the outputs from the printer port can be at a random logic levels
    so the drivers could easily be enabled when you don't want it to be

    for charge pump circuits to work the printer port usually sends a 10Khz signal to enable the system
    when the PC crashes its unlikely to send a signal that can enable the charge pump circuit

    as I don't have any experience with motion controllers I can not be sure if they have an equivalent to a charge pump circuit
    other members should be able give you more information

    John



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    Default Re: Charge pump

    Quote Originally Posted by john-100 View Post
    when a PC crashes the outputs from the printer port can be at a random logic levels
    so the drivers could easily be enabled when you don't want it to be

    for charge pump circuits to work the printer port usually sends a 10Khz signal to enable the system
    when the PC crashes its unlikely to send a signal that can enable the charge pump circuit

    as I don't have any experience with motion controllers I can not be sure if they have an equivalent to a charge pump circuit
    other members should be able give you more information

    John
    A motion controller is an external logic, a signal generator using a microcontroller or an FPGA and ofcourse it can do charge pump function.
    The signals generation is no more happening on the PC when using a motion controller.
    If the PC crashes then the motion controller will loose communication and it's microcontroller can do the proper steps to for example turn off an enable or charge pump output signal.



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