Michael - I think I have it ringt, but will try to re-check tonight.
Thanks,
David
-----Original Message-----
From: Michael Rigby-Jones [mailto:mrjones@NORTELNETWORKS.COM]
Sent: Tuesday, February 08, 2000 9:31 AM
To: PICLIST@MITVMA.MIT.EDU
Subject: Re: Motor Feedback
-----Original Message-----
From: Fansler, David [SMTP:DFANSLER@AUTOCYTE.COM]
Sent: Tuesday, February 08, 2000 1:52 PM
To: PICLIST@MITVMA.MIT.EDU
Subject: OT: Motor Feedback
I have an autohelm for my sailboat that I would like to replace the
"smarts"
with a PIC. The motor has a small circuit board attached to it that I feel
is some sort of feedback circuit. My analog skills have never been a strong
point, and wanted to take advantage of the list to see if someone out there
could give me an educated guess to this circuit. I contacted Maxon to see
if it was one of their feedback units, but they stated that motor was a
special order with no feedback. The unit runs from 12vdc
Thanks
David
Red
|
27 ohm | .3 ohm power resistor
Yel -----/\/\/\/\/\----|----/\/\/\/\/\/--|
| |
| 220 ohm |
|----/\/\/\/\/\/----|---Motor------|
|
|----------|
| |
Blue Green
Just in case the ASCII art gets distorted, there is a yellow wire
that
feeds a 27 ohm and a 220 ohm resistor.
The other end of the 27 ohm goes to a red wire and a .3 ohm power resistor.
The other end of the 220 resistor goes
to one terminal of the motor, and to a Blue wire and a Green wire. The
other end of the .3 ohm power resistor goes to the 2nd terminal of the
motor.
Are you absolutely sure that the blue and the green are tied together? My
first guess would be that the 0.3R resistor is for current measuring
purposes, and the 27R and 220R provide a reference voltage to the control
electronics. However, to sense current there would have to be a wire
comming from the junction of the 0.3R resistor and the motor.
Cheers
Mike