Today's Message Index:
----------------------
1. 11:59 AM - Re: led trim display (spcialeffects)
2. 03:49 PM - Trim position indicator (donjohnston)
3. 04:32 PM - Re: Trim position indicator (Matt Dralle)
4. 04:52 PM - Re: Trim position indicator (Alec Myers)
5. 05:43 PM - Re: Trim position indicator (donjohnston)
6. 06:34 PM - Re: Trim position indicator (Robert L. Nuckolls, III)
7. 06:52 PM - Re: Trim position indicator (ashleysc@broadstripe.net)
8. 07:20 PM - Re: Trim position sensor (user9253)
Message 1
INDEX | Back to Main INDEX |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
Subject: | Re: led trim display |
nuckolls.bob(at)aeroelect wrote:
> At 07:18 AM 8/29/2013, you wrote:
>
>
> > Hi Bob
> >
> > The Europa that I am building uses a Ray Allen for pitch trimming. I have
read over the years that some folks have the same problem you are experiencing
when transmitting. It seems that the greatest success is keeping the wire run
as far from antenna and associated wires as you can. I installed 5 conductor
twisted with shielding from ACS:
> >
> > http://www.europaowners.org/main.php?g2_itemId=30484 (http://www.europaowners.org/main.php?g2_itemId=30484)
> >
> > Ron Parigoris
>
> After pondering schematics for the trim indicator,
> the reason for it's sensitivity to RF becomes
> apparent. The design was never evaluated and
> crafted for immunity to RF interference. There
> are critical components missing from the design.
>
> I note further that voltage used to excite the
> potentiometer in the actuator is the rudimentary
> 1.2 volts supplied by the internal reference
> regulator. An excerpt from the LM3914 specifications
> states . . .
>
> [img]cid:.0[/img]
>
>
> A higher reference voltage increases noise immunity
> for the A/D conversion and less jitter or uncertainty
> in the bar-to-bar transitions for the display. I would
> have considered at least a 5v reference and probably
> some higher value still by adding R1/R2 as described
> above.
>
> Referring to the data sheet again we see that bias (or
> input load) current at the signal pin (5) is 100nA or
> less.
>
> [img]cid:.1[/img]
>
> This means that we could put a resistor in series with
> pin (5) of say 10,000 ohms and exert less than 1 millivolt
> of error in the signal voltage. At the same time we would
> add say 1000pF capacitor from pin 5 to ground (pin 2).
>
> This mod alone might fix the RF sensitivity problem. As
> a matter of good design practice I would bypass the power
> input pin (3) to ground as well.
>
> The designers also missed a great opportunity to make
> their product truly 'universal' by not exploiting the
> expanded scale voltmeter example in the specifications.
>
>
> [img]cid:.2[/img]
>
> Adding a few components and a couple of pots would
> allow the indicator to be tailored to a specific installation
> such that full down trim would illuminate the bottom led,
> full up trim the top led . . . irrespective of the actuator's
> as-installed stroke.
>
> I offered to help these guys with this product line at
> OSH about 20 years ago but they weren't interested. They
> also appear to have learned nothing new by way of feedback
> from the field as to how their product has been performing.
>
> Getting back to the original query for driving two indicators
> from one actuator pot, a study of the schematics and data
> suggests that two indicators running in parallel on one pot
> will not significantly 'load' the signal. Hence, you can wire
> one indicator to the actuator per installation instructions.
> Then wire the second indicator wire for wire in parallel
> with the first but leave its potentiometer excitation voltage
> wire (orange) floating.
>
> Bottom line is that this indicator would benefit greatly
> from due diligence to rudimentary operating characteristics
> and limitations. Adding the resistor and capacitor described
> above may fix the RF sensitivity issue. The idea that an
> installer should be burdened with careful positioning of
> wires to mitigate design flaws is decidedly un-cool.
>
>
>
> Bob . . .
Hi bob. I have this problem. When I press the PTT the ray Allen led flickers and
dims. I've read your post above but don't really understand what is need to
rectify the problem. In the simplest of language how would I go about to resolve
the problem?
Many thanks Frank
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=463890#463890
Message 2
INDEX | Back to Main INDEX |
PREVIOUS | Skip to PREVIOUS Message |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
Subject: | Trim position indicator |
I'm looking for some idea on how to implement a trim position sensor.
Attached is a picture of the aileron trim mechanism.
DC motor on the right drives a cogged belt with an idler pulley on the left. There
is no limiter on the motor. It can run continuously. When it is unable to
pull the bellcrank, the belt begins slipping.
The mechanism works fine. I'm not looking for a new trim mechanism.
But I would like to know where the system is positioned. I thought about a small
magnet on the belt and then some type of sensor but I think that would be too
coarse.
So I'm wondering if anyone has any ideas on how to implement a sensor.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=463896#463896
Attachments:
http://forums.matronics.com//files/fff_small_544.jpg
Message 3
INDEX | Back to Main INDEX |
PREVIOUS | Skip to PREVIOUS Message |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
Subject: | Re: Trim position indicator |
Hi Don,
I think you want one of these:
https://www.aircraftspruce.com/catalog/elpages/racpos12sensor.php?clickkey=35250
[]
At 03:48 PM 12/13/2016 Tuesday, you wrote:
>
>I'm looking for some idea on how to implement a trim position sensor.
>
>Attached is a picture of the aileron trim mechanism.
>
>DC motor on the right drives a cogged belt with an idler pulley on the left. There
is no limiter on the motor. It can run continuously. When it is unable to
pull the bellcrank, the belt begins slipping.
>
>The mechanism works fine. I'm not looking for a new trim mechanism.
>
>But I would like to know where the system is positioned. I thought about a small
magnet on the belt and then some type of sensor but I think that would be
too coarse.
>
>So I'm wondering if anyone has any ideas on how to implement a sensor.
>
>
>Read this topic online here:
>
>http://forums.matronics.com/viewtopic.php?p=463896#463896
>
>
>Attachments:
>
>http://forums.matronics.com//files/fff_small_544.jpg
>
Matt G Dralle | Matronics | 581 Jeannie Way | Livermore | CA | 94550
925-606-1001 V | 925-606-6281 F | dralle@matronics.com Email
http://www.matronics.com/ WWW | Featuring Products For Aircraft
Message 4
INDEX | Back to Main INDEX |
PREVIOUS | Skip to PREVIOUS Message |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
Subject: | Re: Trim position indicator |
how about a servo potentiometer geared to the idler pulley
On Dec 13, 2016, at 19:30, Matt Dralle <dralle@matronics.com> wrote:
Hi Don,
I think you want one of these:
https://www.aircraftspruce.com/catalog/elpages/racpos12sensor.php?c
lickkey=35250
At 03:48 PM 12/13/2016 Tuesday, you wrote:
m>
>
> I'm looking for some idea on how to implement a trim position sensor.
>
> Attached is a picture of the aileron trim mechanism.
>
> DC motor on the right drives a cogged belt with an idler pulley on the lef
t. There is no limiter on the motor. It can run continuously. When it is un
able to pull the bellcrank, the belt begins slipping.
>
> The mechanism works fine. I'm not looking for a new trim mechanism.
>
> But I would like to know where the system is positioned. I thought about a
small magnet on the belt and then some type of sensor but I think that woul
d be too coarse.
>
> So I'm wondering if anyone has any ideas on how to implement a sensor.
>
>
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=463896#463896
>
>
>
>
> Attachments:
>
> http://forums.matronics.com//files/fff_small_544.jpg
>
Matt G Dralle | Matronics | 581 Jeannie Way | Livermore | CA | 94550
925-606-1001 V | 925-606-6281 F | dralle@matronics.com Email
http://www.matronics.com/ WWW | Featuring Products For Aircraft
Message 5
INDEX | Back to Main INDEX |
PREVIOUS | Skip to PREVIOUS Message |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
Subject: | Re: Trim position indicator |
Hey Matt,
I thought about that. But since this isn't a linear mechanism, I couldn't figure
out how to implement that sensor.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=463899#463899
Message 6
INDEX | Back to Main INDEX |
PREVIOUS | Skip to PREVIOUS Message |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
Subject: | Re: Trim position indicator |
>
>
>But I would like to know where the system is positioned. I thought
>about a small magnet on the belt and then some type of sensor but I
>think that would be too coarse.
>
>So I'm wondering if anyone has any ideas on how to implement a sensor.
Emacs!
There's a family of ten-turn potentiometers. You
might be able to couple one of these to your
idler pulley.
See http://tinyurl.com/gunkre5
Bob . . .
Message 7
INDEX | Back to Main INDEX |
PREVIOUS | Skip to PREVIOUS Message |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
Subject: | Re: Trim position indicator |
Hi Don Johnston;
Ray Allen makes a trim position sender that you could actuate by anchoring one
end and fastening the other to the crank arm. It will not send a "stop" signal
to the trim motor, so you will have to provide some other method of limiting
the stroke of the trim motor.
Cheers! Stu.
----- Original Message -----
From: "donjohnston" <don@velocity-xl.com>
Sent: Tuesday, December 13, 2016 3:48:24 PM
Subject: AeroElectric-List: Trim position indicator
I'm looking for some idea on how to implement a trim position sensor.
Attached is a picture of the aileron trim mechanism.
DC motor on the right drives a cogged belt with an idler pulley on the left. There
is no limiter on the motor. It can run continuously. When it is unable to
pull the bellcrank, the belt begins slipping.
The mechanism works fine. I'm not looking for a new trim mechanism.
But I would like to know where the system is positioned. I thought about a small
magnet on the belt and then some type of sensor but I think that would be too
coarse.
So I'm wondering if anyone has any ideas on how to implement a sensor.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=463896#463896
Attachments:
http://forums.matronics.com//files/fff_small_544.jpg
Message 8
INDEX | Back to Main INDEX |
PREVIOUS | Skip to PREVIOUS Message |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
Subject: | Re: Trim position sensor |
If you fastened a magnet to the belt, mount many magnetic reed switches side by
side (glass touching glass) so that at least one switch will always be activated.
25 switches (part number 934-FLEX-14-20-25) cost about $10 total at Mouser.
Reed switches are most easily activated when the magnet is parallel to the switch.
In other words, the magnet north pole is near one end of the switch and the
south pole is near the other end of the switch. A bar magnet should lay flat
on the belt with its axis perpendicular to the length of the belt.
Perhaps others can design a circuit to convert switch closure to panel display.
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=463902#463902
Other Matronics Email List Services
These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.
-- Please support this service by making your Contribution today! --
|