Thanks for your reply Andy, and yes, PWM would be odd choice for the
BP. I chose PWM for this "lab" project, because in addition to the BP
mill, I have a LCNC router with an analog controlled VFD which is next
in line for a conversion. Getting an analog controlled PWM to work
properly seemed the most challenging, and it forces me to dig a little
deeper into hal. I feel much of what I learn here is applicable to the
Bridgeport, even though I won't be using PWM there.
The Bridgeport does have the split sheave/air motor "vari-speed" setup.
I've removed the pot used by the BOSS control, and fabricated an encoder
wheel with I/R sensor that sits inside a 3D printed housing which bolts
to existing tapped holes in the top of the spindle housing. As much as
I would like to have rigid tapping, I feel the mechanics of that old BP
aren't up to the task, which is why I have just a single encoder and no
index. I've seen a couple of posts from others who have used various
combinations of spindle-at-speed plus others to control the air motor
which I hope to leverage.
Brent
On 1/15/2020 3:06 AM, andy pugh wrote:
On Wed, 15 Jan 2020 at 03:09, Brent Loschen <brent.losc...@gmail.com> wrote:
The DC motor speed is
currently controlled with a pot wiper on a small PWM driver board. The
goals of this test bed are to show spindle RPM , control the DC motor
with 0-5vdc from the 7i76 , and use knowledge gained to convert the BP.
Are you planning to use a VFD and control spindle motor speed, or use
a mechanical variable speed?
If you have a 7i76 then using PWM seems a bit odd, as the 7i76 has a
built-in digital potentiometer for spindle speed control.
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