Need Help! g540 pwm output not getting 100%


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  1. #1
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    Default g540 pwm output not getting 100%

    Guys i was out of the business for a while but i am into the machine again this time i hope for good. Anyway i have a problem and need some advice.

    I am running a 400w dc spindle on a g540 with the pot cables connected to 7,8,9 pins on the controller. all seems to work fine or short of . the thing is i have a control over the speed of the spindle but it can get it's max speed (12000rpm) it only gets close enough to 10000 which is 4.23v ( 7pin ,8pin) . i measured the voltage that gets into the 9 pin and it is 5.00v.

    no matter what i have tried i cant get the maximun rpm . When i am running this through the pot all work fine ( i am getting 5.00v)


    Please advice.

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  2. #2
    Member phomann's Avatar
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    Default Re: g540 pwm output not getting 100%

    Hi,
    That’s normal operation. All semiconductor circuits have a voltage loss across their silicon switching junctions.
    This can be anywhere between 0.2V to 0.7V depending on the materials used in the semiconductor. Germanium has 0.2v loss, silicon 0.7v.

    The solution is to supply the G540 with a power supply higher than 5V, say 5.5 or 6V so that the max output from the G540 is 5V.

    Also the problem you are seeing is exacerbated by your speed controller’s use of a 0-5V control signal. Other systems use a 0-10V control voltage. In this case the percentage of the speed that is lost due to the voltage loss is less ( halved).

    Cheers

    Peter.


    Sent from my iPhone using Tapatalk Pro

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    Homann Designs - http://www.homanndesigns.com


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    Default Re: g540 pwm output not getting 100%

    Thanks mate.

    Sent from my ASUS_Z00AD using Tapatalk



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    Member shisa7807's Avatar
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    Default Re: g540 pwm output not getting 100%

    Can you show me how you have it configured in Mach3? I can't seem to get the PWM to control the spindle.

    My connections are as follows:
    To turn on/off the spindle
    DCM(Com) --> G540 P12
    FOR --> G540 P5

    To control spindle
    10V --> G540 P9
    VI -->G540 P8
    ACM --> G540 P7

    and attached is the ports and pin setting in Mach3

    Attached Thumbnails Attached Thumbnails g540 pwm output not getting 100%-motor-outputs-jpg   g540 pwm output not getting 100%-spindle-setup-jpg  


  5. #5
    Member phomann's Avatar
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    Default Re: g540 pwm output not getting 100%

    Have you configured the VFD to accept the speed control from the analog input and not the VFD panel potentiometer?

    Same goes with the FWD terminal.

    Cheers

    Peter.


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    Homann Designs - http://www.homanndesigns.com


  6. #6
    Member shisa7807's Avatar
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    Default Re: g540 pwm output not getting 100%

    Thanks Phomann for your reply. I think I have the VDF configured correctly, FOR = Run and VI (analog input) = 10V.



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g540 pwm output not getting 100%

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