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PWM analog signal reversed in one direction only
Posted:
Wed Jan 12, 2022 8:44 pmby keithathome
My first post and seeking some direction.
I have a uc300 and c76 board. My problem is when operating in CCW the analog signal operates normally. When operating in the clockwise direction the 24,000 rpm signal is 0 and 10 RPM is 10 volts.
Been searching but cannot find a solution.
Thank you, Keith
Re: PWM analog signal reversed in one direction only
Posted:
Thu Jan 13, 2022 4:08 pmby keithathome
Just a note on my testing. I have checked the voltages to the VFD. In CW S12000 is 5 v. When I enter s24000 the voltage runs up to 9.9 volts. CCW or m4 at s12000 is 5 volts as I increase the s value the voltage drops to 0, but enter s1000 and I am getting nearly 9.7 volts.
Re: PWM analog signal reversed in one direction only
Posted:
Sat Jan 15, 2022 12:34 amby cncdrive
There is no such functionility in the UCCNC to change the analog output polarity or the PWM duty cycle polarity depending on the spindle direction (M3 or M4).
So, if it works that way then something is probably wrong with the board.
Or maybe CNC4PC did this on purpose on their board.
What I mean is that the C76 motherboard is made by CNC4PC and I don't know the circuit, but it would be possible to build a board which takes the M3/M4 signal and change the PWM polarity based on that.
Please check the C76 manual if there is an option for this?
Or contact CNC4PC and report this issue to them and ask them if this is a "feature" or a "problem" of the C76 motherboard.