Subject:
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Re: "Servo" Driver for NQC
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Newsgroups:
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lugnet.robotics
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Date:
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Tue, 29 Jan 2002 19:15:03 GMT
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Original-From:
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Steve Baker <sjbaker1@airmail.net+antispam+>
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Reply-To:
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SJBAKER1@AIRMAIL.nomorespamNET
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Viewed:
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2171 times
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Matthias Jetleb wrote:
> Several years ago I built a
> controller for an N scale train set where I used a pulse width
> modulation technique (which is what you're describing) to drive the
> engines around. This system works very well, but the frequency must be
> fairly high. If you slow the frequency down considerably you get
> exactly what you described - jerky on-off motion. I'm somewhat of the
> opinion that the NQC doesn't allow you to toggle the power fast enough
> to make the motion smooth.
But it doesn't need to. The 'power' settings built into the RCX firmware
are already using pulse-width modulation to adjust the amount of power
the motor delivers.
----------------------------- Steve Baker -------------------------------
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Message has 3 Replies:
 | | Re: "Servo" Driver for NQC
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| "Steve Baker" <lego-robotics@crynwr.com> wrote in message news:3C56F4B7.FC698E...ail.net... (...) Then why doesn't it work? :-/ At lower power settings, all it seems to do is sit there and humm, not wanting to go. It really dosen't work that well in (...) (25 years ago, 30-Jan-02, to lugnet.robotics)
| | | Re: "Servo" Driver for NQC
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| (...) <snip> (...) Right, but in the firmware PWM, it is 'on-float-on-float' not 'on-brake-on-brake' I think (but I'm not sure). In fact, the 'on-brake-on-brake' is a neat way to get fine control to (say) just crack a pneumatic valve to move a (...) (25 years ago, 30-Jan-02, to lugnet.robotics)
| | | Re: "Servo" Driver for NQC
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| (...) Yes, but only one of 8 settings (why not all 256??? I don't understand why they limited this). Sometimes only 8 settings doesn't give you enough finesse. Matthias Jetleb (25 years ago, 2-Feb-02, to lugnet.robotics)
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Message is in Reply To:
| | Re: "Servo" Driver for NQC
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| (...) Well I haven't seen your version of the Project-X design, but I'll assume it's similar (albeit vastly inferior) to the one I'm entering. I'm assuming that for the sake of speed, you are keeping moving mass to a minimum and hence, not loading (...) (25 years ago, 30-Jan-02, to lugnet.robotics)
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