Today's Message Index:
----------------------
1. 06:46 AM - Re: testing a coax lead (MLWynn@aol.com)
2. 07:49 AM - Re: Trio Avionics ProPilot 130 Mhz interference problem (was n (Eric M. Jones)
3. 07:57 AM - Re: testing a coax lead (Robert L. Nuckolls, III)
4. 09:28 AM - Re: circuit protection on contactors (Jeff Luckey)
5. 09:42 AM - Re: circuit protection on contactors (Dj Merrill)
6. 10:35 AM - Re: circuit protection on contactors (R&J. Curtis)
7. 02:41 PM - Re: Re: Trio Avionics ProPilot 130 Mhz interference problem (was n (Robert L. Nuckolls, III)
8. 03:26 PM - Info on MGL Enigma (Richard Girard)
9. 04:20 PM - Re: Info on MGL Enigma (Charlie England)
Message 1
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| Subject: | Re: testing a coax lead |
Hi Bob,
It makes sense to start with an ohm meter just to look for continuity. I
guess the next thing would be a coin flip to see which end to break open.
Replacing the right angles on both ends should take care of the issue.
Unless I do that, I won't know that I have fixed the issue unless something
comes up in the continuity check.
I do have an R400 crimp tool. I bought that and pretty much all my wiring
stuff from B&C. Very good folks to do business with. They offer a right
angle adaptor but not a right angle connector. Steinair offers them at
$17.50 a pop. Yikes! I suppose in the overall scheme of things, that is just
a drop in the proverbial bucket. It will cost more than that to get the
transponder certification guy out again.
If you have a spare dedicated right angle connector or two you are willing
to donate to a worthy cause, that would be great. Otherwise, unless I can
find an obvious error in my crimping or connectors, I will buy them from
Steinair.
As usual, thank you for your insights. The Aeroelectric Connection and
this forum have been completely invaluable in planning and executing the
wiring of my plane.
Regards,
Michael Wynn
RV 8 Mostly Finished
San Ramon, CA
In a message dated 5/29/2014 5:47:43 P.M. Pacific Daylight Time,
nuckolls.bob@aeroelectric.com writes:
At 11:18 PM 5/28/2014, you wrote:
Hi folks,
I am about to fly my RV 8 for the first time. Finished construction and
am now tracking down glitches. I had a guy out to certify my pitot, static
and transponder today. Pretty funny sequence. First, we couldn't get
altitude data to the transponder. Turns out that you have to turn on the
serial data feed in a GRT EFIS. Next, turned out the feed pin on was sub-D
connector into the transponder was in the wrong spot. Finally got a read-out
on the altitude. Last problem, the transponder signal was really weak.
We disconnected the antenna and plugged the transponder directly into his
tester. The unit, a Garmin 327, was working fine. That leaves the
antenna and leads.
I used a right angle adaptor as described in the comic book. One from
the transponder and one into the antenna. Seems highly unlikely that there
is a break in the cable itself. More likely, one of the connectors or the
right angle adaptors is at fault.. Any good ideas about how to test this?
I don't want to have the certification technician come out again until I am
sure I have solved the problem. I also don't want to tear out the entire
cable and start over--really inconvenient at this juncture. I didn't leave
enough slack to cut off the connecters and start over so really, I just
need to diagnose the location of the fault and repair it.
Two questions: how to track down the fault; how to test the line and/or
antenna to make sure it is functioning properly prior to calling out the
technician again.
Unfortunately, doing SWR checks on antennas
at this frequency is beyond the range of most
pieces of amateur radio equipment.
Do an ohmmeter check from center pin to
center pin . . . from connector body
to connector body . . . I've never experienced
any problems the po' boy's right angle
connector . . . but simply replacing the
DIY with an on-purpose connector wouldn't
hurt. Do you have a RG-400 connector crimp
tool?
I can send you a connector.
Bob . . .
Message 2
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| Subject: | Re: Trio Avionics ProPilot 130 Mhz interference problem |
(was n
I designed PCBs for medical devices for 25 years. Some very high-power devices
were so quiet that the test lab couldn't tell if the devices were on or not. So
a device like Trio Avionics ProPilot and its interference problem does not seem
to be a difficult fix. Changing the Xtal DOES seem like a bean-counter fix,
but sometimes that is the only way to go. I'd LOVE to inspect the PCB.
In the future Bob and many PCB layout gurus can suggest how to build a PCB and
case that will generate fewer customer problems. My absolute conviction is:
1) Short and decoupled clock line;
2) Four layer PCB (solves 90% of the problems).
3) Examine and minimize every single current loop.
I can suggest Kimmel and Gerke of course, but also many online guides like:
http://www.ti.com/lit/an/scaa082/scaa082.pdf
--------
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge, MA 01550
(508) 764-2072
emjones(at)charter.net
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=424034#424034
Message 3
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| Subject: | Re: testing a coax lead |
At 08:45 AM 5/30/2014, you wrote:
>Hi Bob,
>
>It makes sense to start with an ohm meter just to look for
>continuity. I guess the next thing would be a coin flip to see
>which end to break open. Replacing the right angles on both ends
>should take care of the issue. Unless I do that, I won't know that
>I have fixed the issue unless something comes up in the continuity check.
A reasonable conclusion. Do you have DIY rt angle
connectors on both ends?
>
>I do have an R400 crimp tool. I bought that and pretty much all my
>wiring stuff from B&C. Very good folks to do business with. They
>offer a right angle adaptor but not a right angle
>connector. Steinair offers them at $17.50 a pop. Yikes! I suppose
>in the overall scheme of things, that is just a drop in the
>proverbial bucket. It will cost more than that to get the
>transponder certification guy out again.
You're right. The short path to success
is to simply replace 'em . . .
I'll give B&C a heads-up on a
more economical alternative. Shoot me
your mailing address and I'll get some
connectors in the mail to you today.
>
>If you have a spare dedicated right angle connector or two you are
>willing to donate to a worthy cause, that would be
>great. Otherwise, unless I can find an obvious error in my crimping
>or connectors, I will buy them from Steinair.
>
>As usual, thank you for your insights. The Aeroelectric Connection
>and this forum have been completely invaluable in planning and
>executing the wiring of my plane.
It's called the exercise of spontaneous organization.
Groups of willing and able individuals gathering the
sum of their time, talents and resources together
in quest of a common goal. Took me 50+ years to
acquire an understanding of the phenomenon . . . it's
been going on for thousands of years. Works every
time its tried but really easy to derail.
I'm pleased that this List has been largely
immune to derailments . . .
Bob . . .
Message 4
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| Subject: | Re: circuit protection on contactors |
=0AI agree w/ everything that Vern said and add that this circuit is unique
in that the length of the positive wire which provides power for the coil
is usually very short - only an inch or two - from the big positive termina
l to the little coil terminal on the relay/solenoid and that's why we can g
et away with no circuit protection.- This is not the case with almost all
other circuits.=0A=0A-Jeff=0A=0A=0A=0AOn Thursday, May 29, 2014 11:21 PM,
Sprocket <sprocket@vx-aviation.com> wrote:=0A =0A=0A=0A--> AeroElectric-Lis
t message posted by: Sprocket <sprocket@vx-aviation.com>=0A=0AThe practice
is to protect against wires shorting to ground. The circuit protection trip
s due to large fault current.=0A=0AThe master or e-bus contactor control wi
res operate by grounding the conductor with a switch.- The current in thi
s circuit is limited by the resistance of the contactor coil, so it needs n
o protection.- A short on this wire may cause undesirable behaviour, but
it won't melt or catch fire.=0A=0AVern=0A=0A==========
==================0ASent from my iThing.
It is responsible for all gramma and typo terrors.=0A=0A> On May 29, 2014,
at 8:09 PM, Dj Merrill <deej@deej.net> wrote:=0A> =0A> --> AeroElectric-Lis
t message posted by: Dj Merrill <deej@deej.net>=0A> =0A> We generally put s
ome form of circuit protection (fuse, breaker, etc) on most of our circuits
, including the circuit to activate the starter contactor, but we usually d
o not put any type of protection on the circuit to activate the master cont
actor or E-bus contactor.=0A> =0A> I am curious, why is this?=0A> =0A> Than
ks,=0A> =0A> -Dj, in the middle of re-wiring for a panel upgrade=0A> =0A> -
- =0A> Dj Merrill - N1JOV - VP EAA Chapter 87=0A> Sportsman 2+2 Builder #71
18 N421DJ - http://deej.net/sportsman/=0A> Glastar Flyer N866RH - http://de
=- - - - - - - - - - - - - - - -Matt Dralle
========
Message 5
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| Subject: | Re: circuit protection on contactors |
Thanks all, that makes sense!
-Dj
On 5/30/2014 12:27 PM, Jeff Luckey wrote:
>
> I agree w/ everything that Vern said and add that this circuit is
> unique in that the length of the positive wire which provides power
> for the coil is usually very short - only an inch or two - from the
> big positive terminal to the little coil terminal on the
> relay/solenoid and that's why we can get away with no circuit
> protection. This is not the case with almost all other circuits.
>
> -Jeff
>
>
> On Thursday, May 29, 2014 11:21 PM, Sprocket
> <sprocket@vx-aviation.com> wrote:
>
>
> <sprocket@vx-aviation.com <mailto:sprocket@vx-aviation.com>>
>
> The practice is to protect against wires shorting to ground. The
> circuit protection trips due to large fault current.
>
> The master or e-bus contactor control wires operate by grounding the
> conductor with a switch. The current in this circuit is limited by
> the resistance of the contactor coil, so it needs no protection. A
> short on this wire may cause undesirable behaviour, but it won't melt
> or catch fire.
>
> Vern
--
Dj Merrill - N1JOV - VP EAA Chapter 87
Sportsman 2+2 Builder #7118 N421DJ - http://deej.net/sportsman/
Glastar Flyer N866RH - http://deej.net/glastar/
Message 6
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| Subject: | Re: circuit protection on contactors |
I agree w/ everything that Vern said and add that this circuit is unique
in that the length of the positive wire which provides power for the
coil is usually very short - only an inch or two - from the big positive
terminal to the little coil terminal on the relay/solenoid and that's
why we can get away with no circuit protection. This is not the case
with almost all other circuits.
As a matter of fact most installations have no external wire going
from the Fat Battery terminal to the coil. It is contained inside the
sealed contactor so there is no access to it.
Roger
Message 7
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| Subject: | Re: Trio Avionics ProPilot 130 Mhz interference |
problem (was n
At 09:48 AM 5/30/2014, you wrote:
I designed PCBs for medical devices for 25 years. Some very
high-power devices were so quiet that the test lab couldn't tell if
the devices were on or not. So a device like Trio Avionics ProPilot
and its interference problem does not seem to be a difficult fix.
Changing the Xtal DOES seem like a bean-counter fix, but sometimes
that is the only way to go. I'd LOVE to inspect the PCB.
Makes two of us . . . I've offered . . . we'll
see . . .
In the future Bob and many PCB layout gurus can suggest how to build
a PCB and case that will generate fewer customer problems. My
absolute conviction is:
1) Short and decoupled clock line;
2) Four layer PCB (solves 90% of the problems).
3) Examine and minimize every single current loop.
Yup . . . another great prophylactic is to
use micro-controllers where all the i/o
and clocking is on-board . . . the radiation/
susceptibility apertures are exceedingly
small on a chunk of LSI silicon!
Sometimes you're hosed . . . working a project
now that duty-cycle switches a PM motor at
300 amps and 14 Khz . . . they're closed to
taming this beast but it wasn't easy.
I can suggest Kimmel and Gerke of course, but also many online guides like:
http://www.ti.com/lit/an/scaa082/scaa082.pdf
Absolutely. Took their three-day seminar about
20 years ago from Mr. Kimmel hisself. Good
teacher with eye-opening revelations to offer.
Bob . . .
Message 8
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| Subject: | Info on MGL Enigma |
While trying to fathom why the CHT readings on the MGL Enigma EFIS had
stopped on my friend's Rotax 912 powered JA Highlander I delved into the
manual for the EFIS and its RDAC unit (the box that all senders report to
before their data is passed along to the EFIS).
On page 6 or so of the RDAC manual there is a picture of the back of the
Enigma with a note that the battery under a rectangular cover should be
changed every two years. Upon removing said cover I discovered a CR2032
lithium battery. I checked its voltage output and found it to be 2.9 volts.
A new one that the aircraft owner just happened to have in his tool kit (he
maintains medical equipment for a living) put out 3.3 volts so we replaced
the old one.
More investigation into the setup menus for EFIS revealed that there is an
option for a Rotax sender for the CHT setup and when we checked the unit we
found it had reset to a J type thermocouple. Resetting it to the Rotax
sender solved the problem and the EFIS began reporting good CHT values.
Curious to find out if the low output of the CR2032 was responsible for the
glitch in the CHT setup I delved into the manual for the EFIS and could
find no reference to it in the manual's table of contents, index, or during
a long skim of its contents. The same was true of the RADC manual with the
exception of the picture and note mentioned earlier.
Now we find that the same thing has happened to the oil pressure reading.
Again the setup has been changed to reflect a different type of sender,
only this time restoring it to the Rotax sender option has not fixed it.
There are two sender options for each of resistive type senders and voltage
type. On either resistive option (the Rotax option is a resistive sender)
the bar graph on the EFIS locks up and does not read. When I set it to
either of the voltage type it then reads but it reads backward, i.e. as the
engine revs up the reading drops and vice versa.
The oil pressure sender is a VDO unit and I have located it in VDO's
technical offerings online. VDO recommends that the sender be installed dry
with no teflon tape or thread sealant so that it will ground properly so we
have an investigative path when we return to the airplane this weekend.
MGL has taken the Enigma technical info off line and the aircraft's owner
has not been able to find any information on the CR2032 battery as to what
it does or how to change it properly.
Does anyone out there know about it?
Thanks,
Rick Girard
It isn't necessary to have relatives in Kansas City in order to be unhappy.
- Groucho Marx
Message 9
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| Subject: | Re: Info on MGL Enigma |
On 5/30/2014 5:25 PM, Richard Girard wrote:
> While trying to fathom why the CHT readings on the MGL Enigma EFIS had
> stopped on my friend's Rotax 912 powered JA Highlander I delved into
> the manual for the EFIS and its RDAC unit (the box that all senders
> report to before their data is passed along to the EFIS).
> On page 6 or so of the RDAC manual there is a picture of the back of
> the Enigma with a note that the battery under a rectangular cover
> should be changed every two years. Upon removing said cover I
> discovered a CR2032 lithium battery. I checked its voltage output and
> found it to be 2.9 volts. A new one that the aircraft owner just
> happened to have in his tool kit (he maintains medical equipment for a
> living) put out 3.3 volts so we replaced the old one.
> More investigation into the setup menus for EFIS revealed that there
> is an option for a Rotax sender for the CHT setup and when we checked
> the unit we found it had reset to a J type thermocouple. Resetting it
> to the Rotax sender solved the problem and the EFIS began reporting
> good CHT values.
> Curious to find out if the low output of the CR2032 was responsible
> for the glitch in the CHT setup I delved into the manual for the EFIS
> and could find no reference to it in the manual's table of contents,
> index, or during a long skim of its contents. The same was true of the
> RADC manual with the exception of the picture and note mentioned earlier.
> Now we find that the same thing has happened to the oil pressure
> reading. Again the setup has been changed to reflect a different type
> of sender, only this time restoring it to the Rotax sender option has
> not fixed it. There are two sender options for each of resistive type
> senders and voltage type. On either resistive option (the Rotax option
> is a resistive sender) the bar graph on the EFIS locks up and does not
> read. When I set it to either of the voltage type it then reads but it
> reads backward, i.e. as the engine revs up the reading drops and vice
> versa.
> The oil pressure sender is a VDO unit and I have located it in VDO's
> technical offerings online. VDO recommends that the sender be
> installed dry with no teflon tape or thread sealant so that it will
> ground properly so we have an investigative path when we return to the
> airplane this weekend.
> MGL has taken the Enigma technical info off line and the aircraft's
> owner has not been able to find any information on the CR2032 battery
> as to what it does or how to change it properly.
> Does anyone out there know about it?
>
> Thanks,
> Rick Girard
>
> It isn't necessary to have relatives in Kansas City in order to be
> unhappy.
> - Groucho Marx
>
I can't help with specific info on the MGL, but using that battery for
'backup' is fairly common in electronics. If you use a desktop PC, odds
are good that there's one on the motherboard. My old Garmin III Pilot
gps has one in it. (Note that they make that case style in both a
lithium 'primary' battery, and a lithium rechargeable battery, & it's
sometimes difficult to tell which the mfgr is using.) In the
applications I've seen, the battery keeps a CMOS memory alive, and
that's where basic configuration settings are stored in a lot of
devices. If the battery goes too low to keep the CMOS memory active, the
device will forget whatever settings were stored there. I would think
that more current tech, especially in an a/c device, would avoid using
CMOS memory & the required battery, but some really high dollar avionics
still use it.
On many PC's, if the battery dies, after battery replacement you
sometimes have to do a 'hard reset' by shorting a pair of pins on the
motherboard to completely clear the CMOS memory before re-entering all
the parameters needed.
Sounds like it's time for a Skype call to S Africa. :-)
Charlie
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