* Tutorial * PWM DC motor control with PC ISA card
Paul Oh
Visit: http://www.boondog.com
Pulse-width-modulation (PWM) is a common technique used to control motor
speed. It relies on controlling on/off timing. Standalone PWM circuits
using the 555 timer chip are quite common, but are not easy to interface
to a PC...
The 8254 Timer/Counter chip however is... a complete tutorial
on building your own ISA card (plugs into your PC's motherboard like
a sound or modem card) using this widely available chip can be
found on http://www.boondog.com - there is also a complete tutorial
on applying the 8254 to control a DC motor.
Visit and enjoy the free downloads:
Paul Oh
Boondog Automation
http://www.boondog.com
PRR
Paul E. Bennett
pa...@dynasty.cs.columbia.edu "Paul Oh" writes:
To think that I have managed to do without such a chip for all my products.
My two-motor controller used the RTX2001 and also managed to deal with
implementing AtoD conversion for the Joystick and looked after the safety
aspects. The only PC in use was the one that downloaded the code to the
RTX board. These days, most people doing a low-volume production run would
probably go with a FPGA or a PIC chip or similar.
--
Paul E. Bennett ................... <p...@tcontec.demon.co.uk>
Forth based HIDECS Consultancy
Tel: +44 (0)7971-620145
Going Forth Safely
The Sokos Family
a single digital output line, and you can impliment the timer in software.
You just can't use windows, because you usually need to up the timer
tick frequency to something more usable for PWM.
I've used the printer port and in some cases a dedicated digital output
card (so the printer port could be used for, uh, printing...). I've never
needed
to use an external timer chip.
FYI, for a different approach, there's a short article describing PWM
control
of a solenoid using the printer port on my web page. The only external
circuitry
is what's needed to actually drive the solenoid.
--
Mark Sokos - Electrical Engineer, Computer Geek
(er, programmer) and no talent bum musician
E-mail: so...@desupernet.net
Web: http://users.desupernet.net/sokos/
comp.arch.hobbyist FAQ, electronics tutorials, etc.
"Paul E. Bennett" wrote in message <930864...@tcontec.demon.co.uk>...
Ron Graham
> FYI, for a different approach, there's a short article describing PWM
> control of a solenoid using the printer port on my web page. The
> only external circuitry is what's needed to actually drive the solenoid.
Can't find the article. More precise address? :-)
One thing I found there that was interesting was your comments on
"mechanical filters." They live! What else would a spring-mass-damper
system (or, maybe you call it "proof mass") BE? :-)
Dr. Ron Graham (RonGr...@aol.com)
the Engineer's Companion, http://members.aol.com/RonGraham1/welcome.html
Paul E. Bennett
so...@desupernet.net "The Sokos Family" writes:
> You don't really need a timer chip to do PWM from a PC. All you need is
> a single digital output line, and you can impliment the timer in software.
> You just can't use windows, because you usually need to up the timer
> tick frequency to something more usable for PWM.
Assuming that your processor is fast enough and capable of efficient coding
of the loop termination aspects. My RTX solution achieved a 20kHz PWM output
from a 10MIPS processor.
The Sokos Family
Ron Graham wrote in message
<01bec496$30000a00$602d...@ANALEX096.grc.nasa.gov>...
>Mark Sokos wrote this:
>
>> FYI, for a different approach, there's a short article describing PWM
>> control of a solenoid using the printer port on my web page. The
>> only external circuitry is what's needed to actually drive the solenoid.
>
>Can't find the article. More precise address? :-)
From the main web page, just hit "electronics" and scroll down. Or,
to get there directly, use:
http://users.desupernet.net/sokos/LPT.TXT
>One thing I found there that was interesting was your comments on
>"mechanical filters." They live! What else would a spring-mass-damper
>system (or, maybe you call it "proof mass") BE? :-)
Oh, all right already! I didn't have anything like that in mind when I wrote
the article. :-)
>Dr. Ron Graham (RonGr...@aol.com)
>the Engineer's Companion, http://members.aol.com/RonGraham1/welcome.html
--