Subject:
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Re: Varying the output voltage?
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Newsgroups:
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lugnet.robotics.rcx.legos
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Date:
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Sat, 14 Jun 2003 08:08:32 GMT
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Viewed:
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3267 times
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"Bluey" <Wolf_and_eagle@spamblock.yahoo.com> writes:
>
> The overall answer is, the RCX is set up only to have
> three voltage levels: +9, 0, and -9.
> The basic options there are On, Off, and Reverse.
Actually there are four, sort of, as for 0 there are float
(contacts separated, infinite resistance) and brake
(contacts shorted, zero resistance).
The standard firmware switches rapidly between on and float
(each cycle takes 8ms), which reduces power but not speed,
unless you have a load.
If you switch between on and brake you can regulate speed,
but this might strain the motors more.
> Now by electronically varying the Pulse Width you get 8/7
> (not sure) levels of power in each direction instead of
> the original 3, that is all you get.
The number of levels depends on the software, the standard
ROM supports 8 (0-7) which correspond to 1-8 on out of 8ms.
I think brickOS has many more levels.
Jürgen
--
Jürgen Stuber <stuber@loria.fr>
http://www.loria.fr/~stuber/
> rot 13 "fr"
"se"
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Message has 2 Replies:
 | | Re: Varying the output voltage?
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| This is what I noticed, comparing the two systems with BrickOS One thing that I noticed was at the lower voltages the needle on my multimeter wavered around a little and it tended to steady at the higher power levels All of the readings were taken (...) (21 years ago, 14-Jun-03, to lugnet.robotics.rcx.legos)
| | | Re: Varying the output voltage?
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| (...) you're right, I forgot float. Thanks for clearing the rest up for me :-) Doesn't the motor itself have a "load" when it works with no actual load? "which reduces power but not speed" Timothy (21 years ago, 15-Jun-03, to lugnet.robotics.rcx.legos)
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Message is in Reply To:
| | Re: Varying the output voltage?
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| (...) The eight different power level pulsing is called "PWM", translation=Pulse width modulation. PWM is the way a digital chip cheats/mimics true analog without a D/A convertor. Since the only output of a digital chip is on or off, there is no (...) (21 years ago, 14-Jun-03, to lugnet.robotics.rcx.legos)
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