[NSRCA-discussion] berg 7 channel Rx
Ed Alt
ed_alt at hotmail.com
Wed Sep 13 21:22:49 AKDT 2006
Great summary Jim, I think this makes it much more understandable.
Ed
>From: "J.Oddino" <joddino at socal.rr.com>
>Reply-To: NSRCA Mailing List <nsrca-discussion at lists.nsrca.org>
>To: "NSRCA Mailing List" <nsrca-discussion at lists.nsrca.org>
>Subject: Re: [NSRCA-discussion] berg 7 channel Rx
>Date: Wed, 13 Sep 2006 21:46:08 -0700
>
>Fred is right that the maximum torque is a function of voltage, the motor
>and the gear train. It occurs when the amplifier delivers a 100% duty
>cycle
>to the motor. Increasing the pulse rate does not increase the duty cycle
>past 100%. Ed is right that most of the time we don't get to 100% and
>adding more pulses will increase the duty cycle closer to 100% and
>therefore
>increase the torque. However, if a servo is set up for 50 pulses per
>second, its minimum pulse to the motor and damping will probably not be
>good
>at 100 Hz and the servo will buzz.
>The new so-called digital servos pulse the motor three times longer per
>frame (with more but shorter pulses) for every receiver pulse and therefore
>advertise three times the holding power. This is only true at small error
>signals (difference between input position commanded and output position)
>and the same logic would apply to doubling the frame rate. You would get
>twice the "holding torque" until you got to 100% duty cycle.
>For what it's worth, I've had nothing but good performance with a Berg six
>channel receiver.
>
>Jim O
>
>----- Original Message -----
>From: "Ed Alt" <ed_alt at hotmail.com>
>To: <nsrca-discussion at lists.nsrca.org>
>Sent: Wednesday, September 13, 2006 8:48 PM
>Subject: Re: [NSRCA-discussion] berg 7 channel Rx
>
>
> > Basically, the way our standard servos work is that they trigger a one
>shot
> > on every pulse received. The output of the one shot is a pulse of
>opposite
> > polarity to the input pulse whose width is controlled by the feedback
>pot
> > position (corresponds to the servo arm position). These two pulses are
> > summed and if any error signal exists (if they don't match exactly in
>pulse
> > width), the error signal is stretched (made wider) and amplified to
>drive
> > the motor in one direction or the other to resolve the error signal.
> >
> > The electronics are "dumb" in a standard servo and within certain timing
> > limits, you should be able to increase the effective output torque by
> > increasing the sampling rate of the pulses that are fed to it. I don't
>know
> > that it would be exactly double, but it should go up. This is because
>the
> > motor is not driven at 100% duty cycle when it's running, i.e., it
>receives
> > a train of stretched pulses, but not a pure DC voltage level.
> >
> > Ed
> >
> >
> > >From: "Fred Huber" <fhhuber at clearwire.com>
> > >Reply-To: NSRCA Mailing List <nsrca-discussion at lists.nsrca.org>
> > >To: "NSRCA Mailing List" <nsrca-discussion at lists.nsrca.org>
> > >Subject: Re: [NSRCA-discussion] berg 7 channel Rx
> > >Date: Wed, 13 Sep 2006 22:16:11 -0500
> > >
> > >Max output torque of a servo is a function of battery supplied voltage,
>the
> > >motor in the servo and the gear ratio.
> > >
> > >Changing the signal line frequency will not alter the servo output
>torque.
> > >
> > >Also.. max torque of a servo can sometimes be a GEAR TRAIN limit.
> > >otherwise it would be impossible to strip a sevo gear in flight. No
>change
> > >to the voltage supplied is going to alter the strength of the gears in
>the
> > >servo.
> > >
> > >It may effectively increase the servo resolution and thus sensitivity
>to
> > >being off center, but it will not increase its available torque.
> > >
> > >It MAY have the servo circuit apply more power at a smaller deviation
>from
> > >"demanded" position... But that is an effect of resolution.
> > >
> > >So.. it may apply full torque available at half the deviation from
>demanded
> > >position... (may be what you MEANT to say...)
> > >
> > >Note that using a dual-inverter "glitch buster"
> > >http://www.uoguelph.ca/~antoon/gadgets/noiserx.htm (especially with
>Futabe
> > >127 DF RX's) will boost the signal line from the RX output (appx 3.8 v
>for
> > >the Futaba 127 when using 4.8 v NiCd pack) to full RX pack voltage.
>This
> > >can increase effective resolution. (especially with long servo leads)
> > >The circuit is INTENDED to filter interference from long leads... and
>it
> > >works. The side effect is almost as good as the intended purpose.
> > >
> > > If you can find the chip to make the circuit... I'm having trouble
> > >finding the DIP (.10 inch pin spacing) I got some .05 in pin spacing
> > >chips... which are going to be harder than heck to solder into the
>circuit,
> > >but should do the job.
> > > ----- Original Message -----
> > > From: Scott Pavlock
> > > To: NSRCA Mailing List
> > > Sent: Wednesday, September 13, 2006 4:59 PM
> > > Subject: Re: [NSRCA-discussion] berg 7 channel Rx
> > >
> > >
> > > {trimmed}
> > > The nice part about this is it gives the ability of any analog servo
>to
> > >output twice its normal torque.
> > > {trimmed}
> > >
> > > Scott Pavlock
> > >
> > >
> > > On 9/13/06, White, Chris <chris at ssd.fsi.com> wrote:
> > > Hi Mike Mueller,
> > >
> > > Oops.I meant to imply "They seem to be okay in low cost
>electrics"J
> > >I'm not ready to try a $50 receiver in a big-buck R/C application
>either.
> > >
> > > Chris
> > >
> > >
> > >
> > >
> >
> >---------------------------------------------------------------------------
>-
> > >
> > > From: nsrca-discussion-bounces at lists.nsrca.org
> > >[mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of mike
>mueller
> > > Sent: Wednesday, September 13, 2006 1:44 PM
> > > To: NSRCA Mailing List
> > > Subject: Re: [NSRCA-discussion] berg 7 channel Rx
> > >
> > >
> > >
> > > I know that Castle took a long time to introduce them to the
>market.
> > >The initial designs that they had right after taking over Berg were not
>up
> > >to the standards they wanted. I'm really impressed with these and can't
> > >wait to try one. I'll also test them in a small IC plane before having
> > >confidence in a pattern plane. The people at Castle are top notch. It's
> > >also good to see an electronic component actually made here in the US.
>Mike
> > >
> > > "White, Chris" <chris at ssd.fsi.com> wrote:
> > >
> > > Hi Mike,
> > > I know some foamie guys are using these and treat them like they
>are
>a
> > > standard.....They should be okay.
> > > Chris
> > >
> > > -----Original Message-----
> > > From: nsrca-discussion-bounces at lists.nsrca.org
> > > [mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of
>Michael
> > > Wickizer
> > > Sent: Wednesday, September 13, 2006 12:24 PM
> > > To: nsrca-discussion at lists.nsrca.org
> > > Subject: [NSRCA-discussion] berg 7 channel Rx
> > >
> > > Anybody have experience with these receivers? At only 8 grams,
>sure
> > > would
> > > be a weight savings in electric applications.
> > >
> > > http://www.castlecreations.com/products/berg_7-channel.html
> > >
> > > Mike
> > >
> > >
> > > _______________________________________________
> > > NSRCA-discussion mailing list
> > > NSRCA-discussion at lists.nsrca.org
> > > http://lists.nsrca.org/mailman/listinfo/nsrca-discussion
> > >
> > > _______________________________________________
> > > NSRCA-discussion mailing list
> > > NSRCA-discussion at lists.nsrca.org
> > > http://lists.nsrca.org/mailman/listinfo/nsrca-discussion
> > >
> > >
> > >
> > >
> > >
> > >
> >
> >---------------------------------------------------------------------------
>-
> > >
> > > Do you Yahoo!?
> > > Get on board. You're invited to try the new Yahoo! Mail.
> > >
> > >
> > > _______________________________________________
> > > NSRCA-discussion mailing list
> > > NSRCA-discussion at lists.nsrca.org
> > > http://lists.nsrca.org/mailman/listinfo/nsrca-discussion
> > >
> > >
> > >
> > >
> > >
> > >
> >
> >---------------------------------------------------------------------------
>---
> > >
> > >
> > > _______________________________________________
> > > NSRCA-discussion mailing list
> > > NSRCA-discussion at lists.nsrca.org
> > > http://lists.nsrca.org/mailman/listinfo/nsrca-discussion
> > >
> > >
> >
> >---------------------------------------------------------------------------
>---
> > >
> > >
> > > No virus found in this incoming message.
> > > Checked by AVG Free Edition.
> > > Version: 7.1.405 / Virus Database: 268.12.3/446 - Release Date:
> > >9/12/2006
> >
> >
> > >_______________________________________________
> > >NSRCA-discussion mailing list
> > >NSRCA-discussion at lists.nsrca.org
> > >http://lists.nsrca.org/mailman/listinfo/nsrca-discussion
> >
> >
> >
>
>
>----------------------------------------------------------------------------
>----
>
>
> > _______________________________________________
> > NSRCA-discussion mailing list
> > NSRCA-discussion at lists.nsrca.org
> > http://lists.nsrca.org/mailman/listinfo/nsrca-discussion
> >
>
>
>----------------------------------------------------------------------------
>----
>
>
>Internal Virus Database is out-of-date.
>Checked by AVG Free Edition.
>Version: 7.1.405 / Virus Database: 268.12.0/439 - Release Date: 9/6/2006
>
>_______________________________________________
>NSRCA-discussion mailing list
>NSRCA-discussion at lists.nsrca.org
>http://lists.nsrca.org/mailman/listinfo/nsrca-discussion
More information about the NSRCA-discussion
mailing list