In case anyone might be interested, I posted my current version of PWM
to VFD setup on the wiki here:
http://wiki.linuxcnc.org/cgi-bin/emcinfo.pl?VFD_Digital/Analog_Interface
Any comments, corrections, improvements are welcomed.
--
Kirk Wallace
http://www.wallacecompany.com/machine_shop/
On Sat, 2011-10-01 at 12:14 +0100, andy pugh wrote:
... snip
I have an idea for a way to use a second opto to discharge the cap
through the same resistor during the low portion of the PWM, which
should be linear at all frequencies, but have never bothered trying
it.
After having more
On Sunday, October 02, 2011 12:37:01 PM Kirk Wallace did opine:
On Sat, 2011-10-01 at 12:14 +0100, andy pugh wrote:
... snip
I have an idea for a way to use a second opto to discharge the cap
through the same resistor during the low portion of the PWM, which
should be linear at all
On 10/02/2011 01:38 PM, emc-users-requ...@lists.sourceforge.net wrote:
After having more experience with getting my PWM to VFD input working,
it comes to my mind that what is behind the VFD input is an ADC, which I
think takes a snap shot (sample/hold) at a frequency. I seem to recall
one VFD
On 1 October 2011 05:57, Kirk Wallace kwall...@wallacecompany.com wrote:
Thanks for all of the replies. I think I solved it by tying the input to
the control common with a resistor and capacitor as shown in the
attached file.
A leaky bucket filter, I think.
The usual input circuit is a
On Saturday, October 01, 2011 07:20:28 AM andy pugh did opine:
On 1 October 2011 05:57, Kirk Wallace kwall...@wallacecompany.com
wrote:
Thanks for all of the replies. I think I solved it by tying the input
to the control common with a resistor and capacitor as shown in the
attached file.
That is pretty slick. I thought you were trying to drive a PWM input on
the drive, not an analog input.
I think you should definitely put that on the wiki someplace.
On 10/1/2011 12:57 AM, Kirk Wallace wrote:
Thanks for all of the replies. I think I solved it by tying the input to
the
On Fri, 2011-09-30 at 10:17 +0100, andy pugh wrote:
... snip
I am not clear what you have here. Are you connecting the Opto output
direct to the speed control pin? Or do you have an RC network that you
haven't mentioned?
I have a direct connection. See attachment. I figured the VFD has it's
On 9/29/2011 9:24 PM, Kirk Wallace wrote:
I'm trying to get my Shizuoka going after being idle during the Summer.
Some of the parts had fallen off. So, in putting it back together I
attended to an issue that bothered me from before. The SPI DAC I use to
feed the 0-10 V input to the spindle VFD
Thanks for all of the replies. I think I solved it by tying the input to
the control common with a resistor and capacitor as shown in the
attached file. I guessed with a 10uF electrolytic and adjusted the
resistor, about 700 Ohms, to get 100% RPM at close to 100% duty. It
works very well, so far.
I'm trying to get my Shizuoka going after being idle during the Summer.
Some of the parts had fallen off. So, in putting it back together I
attended to an issue that bothered me from before. The SPI DAC I use to
feed the 0-10 V input to the spindle VFD wanders a bit and is enough to
notice the
On 09/29/2011 06:24 PM, Kirk Wallace wrote:
I'm trying to get my Shizuoka going after being idle during the Summer.
Some of the parts had fallen off. So, in putting it back together I
attended to an issue that bothered me from before. The SPI DAC I use to
feed the 0-10 V input to the spindle
On Thu, 2011-09-29 at 20:44 -0700, Karl Cunningham wrote:
... snip
The PWM output (duty cycle) is 0 to 1.0. Is it possible you're telling
it to go from 0 to 10, and by the time it reaches 10% of full scale it's
already at 1.0? The 10 volts is only between the opto and the VFD input,
nothing
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