Today's Message Index:
----------------------
1. 01:02 AM - Only to you Dale (Speedy11@aol.com)
2. 06:35 AM - Re: Dynon and EMI (Jim Rodrian)
3. 06:38 AM - Re: Load dump issues (Denis Walsh)
4. 07:13 AM - Re: Dynon and EMI (Dale Martin)
5. 07:37 AM - Re: Load dump issues (Robert L. Nuckolls, III)
6. 08:45 AM - Twisted pair cable (Dave Morris)
7. 09:20 AM - Noobie Questions (Metcalfe, Lee, AIR)
8. 10:05 AM - Compass shielding (Glen Matejcek)
9. 11:28 AM - Re: Noobie Questions (Matt Prather)
10. 12:49 PM - GPS Data port wiring (Gary Liming)
11. 02:32 PM - Re: GPS Data port wiring (Chad Robinson)
12. 02:55 PM - Re: Noobie Questions (Robert L. Nuckolls, III)
13. 03:06 PM - Re: GPS Data port wiring (AI Nut)
14. 04:20 PM - Re: GPS Data port wiring (Gary Liming)
15. 05:21 PM - Re: GPS Data port wiring (AI Nut)
16. 06:00 PM - Compass shielding (hollandm)
17. 07:06 PM - Re: Compass shielding (Dale Martin)
18. 07:28 PM - Re: Compass shielding (Jerzy Krasinski)
19. 07:47 PM - Bus Load Analysis (Dale Martin)
20. 07:49 PM - Re: Compass shielding (Alex Peterson)
21. 08:06 PM - Re: GPS Data port wiring (Jim Corner)
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: | Only to you Dale |
--> AeroElectric-List message posted by: Speedy11@aol.com
Dale,
Guess I misunderstood the original statement. I happen to agree with you on
the dual EI systems.
Stan
In a message dated 2/11/04 2:57:20 AM Eastern Standard Time,
aeroelectric-list-digest@matronics.com writes:
<< How important in the engine driven power supply's when the engine quits?
Maybe you have a use for two alternators right about then but I sure don't.
A very good battery or will give my essential bus the power to do the
required thing and maybe even restart the engine. Alternators have never
started an engine for me yet. This is why a running dual E.I. systems is
nuts to me. If you don't have enough energy to run the systems on battery
power it is a special feeling to know the magneto is not dependant on an
alternate source. >>
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: | Re: Dynon and EMI |
HTML_FONTCOLOR_GREEN, HTML_FONTCOLOR_RED, HTML_FONTCOLOR_UNKNOWN,
--> AeroElectric-List message posted by: "Jim Rodrian" <jim.rodrian@elsyn.com>
Jeff,
Properly designed and tested EMI filtering in a product will work from it's (the
products)
minimum to maximum specified operating voltage. The filters characteristics need
to be matched
to the characteristics of the internal active circuits.
Every product I have designed, from a simple residential water softener control
to industrial
machine controls were / are tested to comply with stringent radiated and conducted
emissions and
susceptibility standards (EMC standards). These tests insure that the product
will not
interfere with other products and are not affected by radiation from other products.
Typically, all connections, not just the power connections, to / from a product
need filtering
to meet the EMC standards. Months ago, Dynon indicated to me that they didn't
have a formal EMC
test program for their product. What you have observed may be a result of that
policy.
James A. Rodrian, P.E. (Defiant)
Grafton, WI
Microprocessor-based product development since 1977.
Time:
01:06:58 PM PST US
From:
Jeff Point <jpoint@mindspring.com>
Subject:
Dynon and EMI
--> AeroElectric-List message posted by: Jeff Point <jpoint@mindspring.com>
Made an interesting discovery today while chasing down the source of EMI
from my Dynon. <snip>
My theory as to why this is, and it is an uneducated SWAG- the noise
filter circuits inside all of the boxes (Dynon, radio and strobe
supplies) are not functioning because of the low voltage, while the
units themselves appear to work. What does anyone think of that?
Jeff Point
RV-6 getting very close
Milwaukee WI
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: Load dump issues |
--> AeroElectric-List message posted by: Denis Walsh <denis.walsh@comcast.net>
I'm getting dizzy.
>
> I was not saying you had said what I was saying.
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: Dynon and EMI |
--> AeroElectric-List message posted by: "Dale Martin" <niceez@cableone.net>
Jim,
When you say filtering - Is that synonymous for shielding? In your
opinion - is the Dynon EFIS missing the mark here or is there a simple
solution for a demanding builder?
Dale Martin
Lewiston, ID
LEZ-235
----- Original Message -----
From: "Jim Rodrian" <jim.rodrian@elsyn.com>
Subject: Re: AeroElectric-List: Dynon and EMI
> --> AeroElectric-List message posted by: "Jim Rodrian"
<jim.rodrian@elsyn.com>
>
> Jeff,
>
>
> Properly designed and tested EMI filtering in a product will work from
it's (the products)
> minimum to maximum specified operating voltage. The filters
characteristics need to be matched
> to the characteristics of the internal active circuits.
>
>
> Every product I have designed, from a simple residential water softener
control to industrial
> machine controls were / are tested to comply with stringent radiated and
conducted emissions and
> susceptibility standards (EMC standards). These tests insure that the
product will not
> interfere with other products and are not affected by radiation from other
products.
>
>
> Typically, all connections, not just the power connections, to / from a
product need filtering
> to meet the EMC standards. Months ago, Dynon indicated to me that they
didn't have a formal EMC
> test program for their product. What you have observed may be a result of
that policy.
>
> James A. Rodrian, P.E. (Defiant)
> Grafton, WI
> Microprocessor-based product development since 1977.
>
>
> Time:
>
> 01:06:58 PM PST US
>
>
> From:
>
> Jeff Point <jpoint@mindspring.com>
>
>
> Subject:
>
> Dynon and EMI
>
>
> --> AeroElectric-List message posted by: Jeff Point
<jpoint@mindspring.com>
>
> Made an interesting discovery today while chasing down the source of
EMI
> from my Dynon. <snip>
>
> My theory as to why this is, and it is an uneducated SWAG- the noise
> filter circuits inside all of the boxes (Dynon, radio and strobe
> supplies) are not functioning because of the low voltage, while the
> units themselves appear to work. What does anyone think of that?
>
> Jeff Point
> RV-6 getting very close
> Milwaukee WI
>
>
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: Load dump issues |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
<snip>
> > That's not what was said. The problem is load-dump tolerance
> > of the REGULATORS internal to rebuilt alternators Van's sells vis-a-vis
> > regulators in OEM alternators which MAY be more resistant.
> > Regulator chips advertised by Onsemi and others call out "load dump
> > protection."
>
>I was not saying you had said what I was saying. My point is that ALL
>alternators internal and external need to be addressed. The fact that Onsemi
>has a regulator with internal load dump does not mean the regulator of a
>2004 alternator has load dump protection. The I/C mfgrs have been pushing
>load dump protection for at last 20 years that I am aware of with limited
>success until recently where modern autos can have thousands of dollars of
>electronics at risk.
>
>I have not seen any hard evidence that Van supplied regulators are of lesser
>quality, circumstantial perhaps but there may be other reasons.
Didn't say there was. this is the WORKING hypothesis that will
have to be proved, disproved or discarded as irrelevant.
>I was trying to point out that the problem may be very widespread (in
>potential)and its only recently that its showing up on Vans acft and perhaps
>there only because of pilot procedures and the large number of these
>experimentals.
The POTENTIAL is certainly widely spread. I don't think anyone
ever said the risk was zero. It did not become a marketplace issue
until Van's noted a demonstrable problem and published
a 'fix' that was short on understanding and increased the risk
of more expensive difficulties in terms of OV failures.
> >
> > I mentioned in a post last week that the externally regulated
> > Bonanza alternators are wired in a way that I could manually
> > generate a "load-dump" event by manipulation of switches.
>
>Yes and I think that any design that allows of improper use of unguarded
>switches results in damage is unacceptable, at least my acft.
>
> I have a friend who has another spam can (high end acft) that blew an
>alternator when the master was pulled when smoke in the cockpit was noticed.
>The smoke cleared and the master was reset and the alternator was NG. Later
>shown to have several diodes shorted presumably due to load dump. There was
>an external reg that was unharmed. This acft was wired by the factory that
>way
Yup, that's the nature of the beast called an FAA certified
flying machine.
> > >All alternators, regardless of design, need protection or they can dump
> > >damaging loads either back to the alternator or to the expensive avionics
> > >depending on what opened and where.
> >
> > Correct. We've had this discussion before. The risk is predicated
> > on battery contactor failure (or pilot operation of the contactor
> > at inappropriate times) while the battery is being charged. After
> > that, the duration and amplitude of the event is dependent upon many
> > system variables.
>
>I agree but a design that allows a pilot to simply throw the wrong switch
>and cause alternator or worse failure is a bad design. Even switch layout on
>the panel is not acceptable to me as we are dealing with Private pilots who
>can make mistakes.
Goodness or badness can debated interminably. Risk however is
readily studied and can be used to make considered decisions
for both design and operation. It is a fact that ANY airplane,
spam can or otherwise can generate the load-dump event by opening
the master switch while the alternator is loaded. If putting
guards over any switches makes someone feel better, so be it.
> > >Designs that disconnect the "B" lead when OVP is detected are great as
>long
> > >as there are Zero false trips. Bob has said many times that his OVP can
>and
> > >does (while very rare) false trip. This can result in alternator damage
>due
> > >to a false trip and not acceptable to me.
> >
> > Correct . . . and the goal of this activity is to make it acceptable
> > to you and the rest of the OBAM aircraft community.
> >
> > But it doesn't seem to be happening except for a limited population
> > of alternators which at the moment are all Van's rebuilts. We'll be
> > testing some factory fresh ND alternators in a few weeks. The working
> > hypothesis of the moment is that it's zero risk to airplane and strong
> > risk only to those alternators with regulators built with technology
> > falling short of what ND might do for a factory fresh product.
>
>I hope you will test curent production ND NEW alternators to prove your
>theory
That's what I said. B&C uses factory fresh ND alternators
as cores for their products. however, I'll suggest that my
testing of these particular alternators will not PROVE my
theory about Van's machines, only confirm that the present
production NDs are relatively immune from damage by load-dump.
The real meat of this test will be to know how much energy
we're talking about and the form it takes.
> > >There are more modern OVP I/C's that have provision for not false
>tripping
> > >on narrow spikes as they have adjustable delay to trip times. I suggest
>that
> > >this design approach be used to prevent a OVP protection device from
> > >causing damage from a not quite perfect design.
> >
> > The OVM-14 and derivatives used in the B&C's products are all
> > adjustable for trip response. After our experience with the
> > super-noisy Bonanza's I belive nuisance tripping from dv/dt
> > effects of very low energy, narrow spikes has been resolved.
> > Thousands of those devices were in service with successful service
> > histories until Bonanza came along . . . and I believe we've
> > slain that dragon as well.
>
>The following is from a recent post of yours and over the years has been
>repeated several times a year. This with regard to the OVP module design you
>have provided to all of us. The LTC1696 is specifically designed so you can
>set the trip pulse width time to avoid nuisance tripping from short spikes.
>This is not possible with your design per your supplied schematic.
>
>"Nuisance tripping of the crowbar ov module is rare but it
> HAS happened and at higher rates than real ov tripping.''
Excuse me? How is the current design not adjustable for
delay? The RC time constant of the voltage sense circuit
can be adjusted for increased or decreased response time.
The LTC1696 is a nice chip. It starts a timer based on
excursions past a threshold and resets the timer if
voltage falls below the threshold before timeout. I've
implemented that function several times for customers
using a non-integrating front end detector driving a
fixed time delay later.
The aircraft industry likes to embrace Mil-STD-704
notions about OV events where integrating the sensed
signal up front makes the ov sensing both TIME and AMPLITUDE
sensitive. They expect to see the ov trip time go down
as the fault voltage goes up. The LTC1696 doesn't work this
way. However, EITHER philosophy can be used to fabricate
an effective ov protection system.
The only nuisance tripping we've experienced in about 10+
years was a marked dv/dt event that first cropped up in
production Bonanzas. We now believe that the few cases
of nuisance tripping we observed before the Bonanza mod
program were similarly generated. Since that time, I've
had no conversation with anyone where their "nuisance trip"
was not ultimately confirmed to be a true ov condition
or overshoot due to poor regulator performance.
> >
> > The only kind of nuisance trip we expect to see now will be an true
> > overshoot of the regulator/alternator combination . . . over which
> > we have no control when our OVM-14 is purchased for combination with
> > other hardware. Nuisance tripping is not a component of the current
> > discussion.
>
> Disagree as we should be addressing every application not just a matched
>set from B&C.
You put words in my mouth again. I said poor combinations of
alternator and regulator. In these cases, I'm talking about regulators
that shouldn't be used on any machine . . . has nothing to do with
B&C's products. These were regulators that would overshoot so badly
on real load-dump (battery still connected) that they tripped
the ov protection.
>As a nuisance trip with out load dump protection can fail the alternator and
>this should not only be addressed but mitigated. Failure of a protection
>device should never cause failure of the device being protected. Just as
>failure to use a specific switching procedure should not damage components.
No argument here.
> >
> > <snip - rhetorical repeat of well known and accepted science>
>
>Then why not include every alternator in the discussion ?, not limit it to
>Vans rebuilt internal alternators
Who was proposing anything different? Again you mis-characterize
my words. My goal is to publish a change to figure Z-24 that will
be a recommended configuration for all installations. I don't
have nor do I want to control the brand or source of alternator
anyone chooses to use. Figure Z-24 is never going to say something
like , "Use this configuration for Brand A but not for Brand X".
It will be recommended for ALL internally regulated alternators.
We'll probably add it to other Z-figures and discuss it in the
chapter on ov protection. This activity will undoubtedly confirm
the size and usefulness of a low cost mitigation philosophy that
might as well be included in all systems . . . although our experience
with both OBAM and certified aircraft has demonstrated this failure
mode be a very low risk.
I'll also present findings from this activity to my fellow sparkies
at RAC. Whether or not anything happens there is problematical.
Return on investment dollars will be tough to justify on such a
rare and probably undocumented event. We're advancing the art
in OBAM aircraft systems design at a rate that far outstrips
the efforts in spam cans.
> > >Bob has suggested that NEW alternators have such protection and so Bob
> > >please let us know specifically which NEW alternators have such
> > >protection built in so we can consider them for our use.
> >
> > I have said no such thing . . . you have mis-characterized my words.
> > I'm not setting myself up as the great arbiter of suitable and
> > unsuitable alternators.
>
>Recent comment from you I was referring to.
>
>""It is therefore my belief that the very popular 40 Amp Denso bought new
>from Niagra has a regulator which has dump logic in it. ""
Simply a statement of fact. Someone suggested that Niagra offered
new ND machines and to date, I've not heard of anyone blowing
a Niagra alternator wired per Z-24. It's true that we may hear
of it tomorrow . . . but for the moment, a simple belief concerning
features they may (or may not) contain. It's not intended to be
a recommendation to anyone. Those will be fully defined when Z-24
is updated and I publish the article on the experiments.
> > You mentioned a fat capacitor across the b-lead as an alternative
> > technique. Interesting . . . a 22,000 uF cap impressed with a 60A
> > constant current pulse rises at 2700 volts/second. So if we wanted
> > to limit the load/battery-dump event to 24 volts max, then
> > the event duration could not exceed about 3.6 milliseconds. Hmmmm . .
>.
> > sounds reasonable. I'm going to look at that too.
>
> I was simply stating that without a battery some regulators are unstable
>and adding a capacitor has been proven to stabilize the regulator. If the
>battery charge current (the source of the load dump) is small when the
>battery is disconnected the capacitor will dampen the spike. It may not be
>of much help with a 50 amp Load dump.
Never can tell. Since you didn't refute or confirm my 3.6 millisecond
hypothesis, we'll still go to the test bench and do the science.
It's an interesting feature to explore.
> >
> > That 500A figure is completely meaningless when cited out of
> > context. ALL TVS devices will carry 500A for some duration.
>
>Its not meaningless IF you take the time to look at the data sheet which was
>my intent. I never intended to provide all the details, just the link. In
>this case the duration is specified at 0.2 second (more than long enough)
>and clearly longer with 1/10 the current we are dealing with vs. the rated
>500 amps.
Now you've qualified your 500A pronouncement in a useful way.
The DATA SHEET for this or any other device offers us insight
to an ability to manage energy. No alternator is going to produce
a 500A surge to any protective device. The original statement
suggested that this 500A device was suitable for any sized alternator.
The number 500 is impressive but irrelevant when pulled out of context.
>Thank you for well thought out replies.
My pleasure sir.
Bob . . .
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: | Twisted pair cable |
--> AeroElectric-List message posted by: Dave Morris <dave@davemorris.com>
Bob, do you have a favorite shielded twisted pair cable that can be used
for various things ahead of the firewall and behind it? Do you like the
Belden 82729 or is there something better?
Thanks,
Dave Morris
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: | Noobie Questions |
--> AeroElectric-List message posted by: "Metcalfe, Lee, AIR" <Lee.Metcalfe@jocogov.org>
I have a Lancair 320 that I bought from the builder. I am planning to
re-wire the electrical system this spring to update it (12 years old)
and replace some amateurish workmanship. I attended Bob's seminar last
weekend and learned a lot, but I still have a lot of questions. I'm
sure I'll be back with more questions as I plan the new system, but here
are my first three...
> None of Bob's Z-figures show any circuit protection in the battery
contactor control circuit (BAT master to battery contactor solenoid).
Is this an oversight or is protection not needed?
> I see no provision for an avionics fan on any of the bus drawings.
Should not the avionics fan be connected to the main bus (or e-bus if
you have one) via circuit protection? The current set-up in my plane is
the avionics fan is hard-wired to a power source (haven't found it yet)
with no circuit protection (confirmed by pulling all circuit breakers
and it still runs with the BAT master on).
> I am planning on using B&C's LR-3 alternator controller. Do I still
need circuit protection on the B-lead, which will be tied to the
switched side of the battery contactor (it is currently tied to the main
(and only) bus through a 35A breaker).
All advice appreciated!
Lee Metcalfe
Flying Lancair 320 (500+ hrs.)
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: | Compass shielding |
--> AeroElectric-List message posted by: "Glen Matejcek" <aerobubba@earthlink.net>
Jerzy-
>Do not bother with shielding the compass, it will not work. The compass
>MUST be exposed to external magnetic field, this is how it finds
>directions.
According to my friends in the HUD manufacturing business, your statement about
shielding the compass rendering it useless is incorrect, at least with respect
to mu metal. I suppose this could be different with flashing material, but
IIRC shielding damps dynamic magnetic fields such as EMI, while the earth's magnetic
field is static from the compass' frame of reference. Having said that,
it still makes more sense from the theoretical perspective to shield the antagonist
rather than the victim. Most likely from the practical application perspective,
also.
Glen Matejcek
aerobubba@earthlink.net
Message 9
| 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: Noobie Questions |
--> AeroElectric-List message posted by: "Matt Prather" <mprather@spro.net>
Hi Lee,
Some good questions. I took a stab at answering them below.
> --> AeroElectric-List message posted by: "Metcalfe, Lee, AIR"
> <Lee.Metcalfe@jocogov.org>
>
> I have a Lancair 320 that I bought from the builder. I am planning to
> re-wire the electrical system this spring to update it (12 years old)
> and replace some amateurish workmanship. I attended Bob's seminar last
> weekend and learned a lot, but I still have a lot of questions. I'm
> sure I'll be back with more questions as I plan the new system, but here
> are my first three...
>
>> None of Bob's Z-figures show any circuit protection in the battery
> contactor control circuit (BAT master to battery contactor solenoid). Is
> this an oversight or is protection not needed?
One side of the master contactor is made hot from by the very short
run to the big lug on the contactor. No protection needed there. The
other side of the contactor, which gets connected to the master
switch, provides a ground path for the contactor to be activated. If this
wire is faulted somewhere, the worst thing that can happen is that the
master contactor stays on all of the time.
>
>> I see no provision for an avionics fan on any of the bus drawings.
> Should not the avionics fan be connected to the main bus (or e-bus if
> you have one) via circuit protection? The current set-up in my plane is
> the avionics fan is hard-wired to a power source (haven't found it yet)
> with no circuit protection (confirmed by pulling all circuit breakers
> and it still runs with the BAT master on).
Maybe (hopefully) there is an in-line fuse to a connection to a battery
bus? Never the less, I like your idea of running any required avionics
fan onto the main bus. I would only connect it to the e-bus if
something on the e-bus actually requires cooling. If an essential piece
of equipment does require supplemental cooling, I would consider
that as a strike against it. It would be nice to shed the load imposed
by fans when on a limited power budget.
>
>> I am planning on using B&C's LR-3 alternator controller. Do I still
> need circuit protection on the B-lead, which will be tied to the
> switched side of the battery contactor (it is currently tied to the main
> (and only) bus through a 35A breaker).
If you are going to stick with a single battery, single alternator system,
I would wire it up like Z-11. The alternator B-lead protection is in the
form of an ANL close to the alternator. In Z-11, the (maybe) long run
from the battery contactor to the engine area is shared between the
starter and the alternator. An elegant setup.
>
> All advice appreciated!
>
> Lee Metcalfe
> Flying Lancair 320 (500+ hrs.)
>
Sounds like a good project.
Matt-
N34RD
Message 10
| 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: | GPS Data port wiring |
--> AeroElectric-List message posted by: Gary Liming <gary@liming.org>
Hello Learned Listers,
I am trying to put a 9 pin serial connector under my panel for the purpose
of allowing a serial (RS-232) connection that comes out of a GPS (a Garmin
196 in this case) so that a laptop can update its map info.
The laptop only has USB ports (they are both USB version 2.0), so I need to
get a USB-to-RS232 converter cable to make the connection.
Two questions:
1. should the 9 pin connector be male or female, and,
2. should the the tx and rx leads be reversed on the connector, or is that
already done in the USB cable?
If someone has already wired this and could let me know in advance of
getting the cable and installing the 9 pin connector, and doing my own
experiments, I would appreciate it.
Thanks,
Gary Liming
Message 11
| 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: GPS Data port wiring |
--> AeroElectric-List message posted by: Chad Robinson <crobinson@rfgonline.com>
Gary Liming wrote:
> --> AeroElectric-List message posted by: Gary Liming <gary@liming.org>
>
>
> Hello Learned Listers,
>
> I am trying to put a 9 pin serial connector under my panel for the purpose
> of allowing a serial (RS-232) connection that comes out of a GPS (a Garmin
> 196 in this case) so that a laptop can update its map info.
>
> The laptop only has USB ports (they are both USB version 2.0), so I need to
> get a USB-to-RS232 converter cable to make the connection.
>
> Two questions:
>
> 1. should the 9 pin connector be male or female, and,
>
> 2. should the the tx and rx leads be reversed on the connector, or is that
> already done in the USB cable?
>
> If someone has already wired this and could let me know in advance of
> getting the cable and installing the 9 pin connector, and doing my own
> experiments, I would appreciate it.
The USB cable creates a port identical to what you would have on the laptop if
you had a real serial port. That is, a 9-pin male DTE (terminal side) port.
Your GPS device almost certainly provides a 9-pin female DCE (communications
side, such as a modem) port. The best option would thus be a 9-pin female
connector, assuming you're creating your own. Wire it straight through, pin
for pin, because the mapping is generally done in the device, not the cable.
If it doesn't work, try a null modem adapter, and if that makes it work it's
usually a simple enough matter to swap pins 2 and 3 so you don't need the
adapter anymore. No reason to lose sleep over it.
Be careful with these USB cables. There are different quality devices, and
some of them are really only designed to connect serial mice to a PC, not any
other type of serial device. That is, they don't actually create serial ports.
Devices based on FTDI's chipset, which you can find dozens of on eBay on an
average day, are a good bet - these provide a device driver that actually
creates a virtual serial port that your map software can talk to.
Regards,
Chad
Message 12
| 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: Noobie Questions |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 11:20 AM 2/11/2004 -0600, you wrote:
>--> AeroElectric-List message posted by: "Metcalfe, Lee, AIR"
><Lee.Metcalfe@jocogov.org>
>
>I have a Lancair 320 that I bought from the builder. I am planning to
>re-wire the electrical system this spring to update it (12 years old)
>and replace some amateurish workmanship. I attended Bob's seminar last
>weekend and learned a lot, but I still have a lot of questions. I'm
>sure I'll be back with more questions as I plan the new system, but here
>are my first three...
>
> > None of Bob's Z-figures show any circuit protection in the battery
>contactor control circuit (BAT master to battery contactor solenoid).
>Is this an oversight or is protection not needed?
Not needed. There's no way you can put that wire at risk.
> > I see no provision for an avionics fan on any of the bus drawings.
>Should not the avionics fan be connected to the main bus (or e-bus if
>you have one) via circuit protection? The current set-up in my plane is
>the avionics fan is hard-wired to a power source (haven't found it yet)
>with no circuit protection (confirmed by pulling all circuit breakers
>and it still runs with the BAT master on).
The Z-drawings are intended only to convey architecture . . . not
details as to what gets powered from which bus or with which size
fuse/breaker. The first documents you need to complete are the
load analysis documents for each bus. See:
http://www.aeroelectric.com/temp/Load_Analysis.pdf
Here is where you account for nearly every device in the
airplane, where it gets power from, under what conditions
it is used and how much power it takes.
Your current fan may be protected with an in-line fuse.
> > I am planning on using B&C's LR-3 alternator controller. Do I still
>need circuit protection on the B-lead, which will be tied to the
>switched side of the battery contactor (it is currently tied to the main
>(and only) bus through a 35A breaker).
The convention is to put a current limiter (fat fuse) in series
with the b-lead to protect the rest of the airplane from the
hazards of shorted diodes in the alternator.
Bob . . .
-----------------------------------------
( Experience and common sense cannot be )
( replaced with policy and procedures. )
( R. L. Nuckolls III )
-----------------------------------------
Message 13
| 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: GPS Data port wiring |
--> AeroElectric-List message posted by: "AI Nut" <ainut@earthlink.net>
That depends upon which converter you get. Take note of the gender on the
laptop, and on the Garmin, then go to a computer store that has gender
matchers, the converter, and cables with different kinds of ends. Make it
if you can't buy it, it isn't hard.
HTH,
AI Nut
----- Original Message -----
From: "Gary Liming" <gary@liming.org>
Subject: AeroElectric-List: GPS Data port wiring
> --> AeroElectric-List message posted by: Gary Liming <gary@liming.org>
>
>
> Hello Learned Listers,
>
> I am trying to put a 9 pin serial connector under my panel for the purpose
> of allowing a serial (RS-232) connection that comes out of a GPS (a Garmin
> 196 in this case) so that a laptop can update its map info.
>
> The laptop only has USB ports (they are both USB version 2.0), so I need
to
> get a USB-to-RS232 converter cable to make the connection.
>
> Two questions:
>
> 1. should the 9 pin connector be male or female, and,
>
> 2. should the the tx and rx leads be reversed on the connector, or is that
> already done in the USB cable?
>
> If someone has already wired this and could let me know in advance of
> getting the cable and installing the 9 pin connector, and doing my own
> experiments, I would appreciate it.
>
> Thanks,
>
> Gary Liming
>
>
Message 14
| 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: GPS Data port wiring |
--> AeroElectric-List message posted by: Gary Liming <gary@liming.org>
At 05:05 PM 2/11/2004 -0600, you wrote:
>--> AeroElectric-List message posted by: "AI Nut" <ainut@earthlink.net>
>
>That depends upon which converter you get. Take note of the gender on the
>laptop, and on the Garmin, then go to a computer store that has gender
>matchers, the converter, and cables with different kinds of ends. Make it
>if you can't buy it, it isn't hard.
Thanks for the help so far, but has anyone wired this up? The Garmin only
provides Tx, Rx, and ground pins on its own round 4 pin connector that also
provides power to the unit, so it is not possible to say if its DTE or DCE
(which determines DSR/DTR and RTS/CTS behavior) or to determine the
connector gender. Presumably this means one does need to connect Rx on the
Garmin to Tx on the 9 pins side of the USB cable as well, but I was hoping
not to get it right the first time.
I am not so much concerned about the ruggedness of the USB cable, since it
is only used to update the GPS data (or unload data to the laptop) while on
the ground.
Thanks again,
Gary Liming
Message 15
| 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: GPS Data port wiring |
--> AeroElectric-List message posted by: "AI Nut" <ainut@earthlink.net>
DTE and DCE only refer to which direction the data flows on which line.
Other (control) lines do various jobs that apparently the Garmin doesn't
need or support.
Gender of the connectors refers merely to whether there are pins (male) or
holes (female.) Purely a mechanical issue.
Very basically, get connectors that will mate the male to the female ends.
Then, connect the tx line from one device to the rx line on the other
device, and vice versa. Ground to ground. Done.
----- Original Message -----
From: "Gary Liming" <gary@liming.org>
Subject: Re: AeroElectric-List: GPS Data port wiring
> --> AeroElectric-List message posted by: Gary Liming <gary@liming.org>
>
> At 05:05 PM 2/11/2004 -0600, you wrote:
> >--> AeroElectric-List message posted by: "AI Nut" <ainut@earthlink.net>
> >
> >That depends upon which converter you get. Take note of the gender on
the
> >laptop, and on the Garmin, then go to a computer store that has gender
> >matchers, the converter, and cables with different kinds of ends. Make
it
> >if you can't buy it, it isn't hard.
>
> Thanks for the help so far, but has anyone wired this up? The Garmin only
> provides Tx, Rx, and ground pins on its own round 4 pin connector that
also
> provides power to the unit, so it is not possible to say if its DTE or DCE
> (which determines DSR/DTR and RTS/CTS behavior) or to determine the
> connector gender. Presumably this means one does need to connect Rx on
the
> Garmin to Tx on the 9 pins side of the USB cable as well, but I was hoping
> not to get it right the first time.
>
> I am not so much concerned about the ruggedness of the USB cable, since it
> is only used to update the GPS data (or unload data to the laptop) while
on
> the ground.
>
> Thanks again,
>
> Gary Liming
>
>
Message 16
| 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: | Compass shielding |
--> AeroElectric-List message posted by: "hollandm" <hollandm@pacbell.net>
The TC may well be Chinese, who can say these days, but it claims to be manufactured
by mid continent, model 1394T100-7Z.
I haven't been able to scratch up any galvanized tin yet and still searching for
a few square inches of mu-metal.
The electrical separation idea is a no-brainer, unfortunately there are no available
places, within my field of vision where that is possible.
Did try twisting the feed line, no effect.
It is definitely related to the electical field generated by gyro motor since it
only shows an effect on the compass when switched on.
Message 17
| 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: Compass shielding |
--> AeroElectric-List message posted by: "Dale Martin" <niceez@cableone.net>
What kind of airplane is it in.... Just curious.
-Dale
----- Original Message -----
From: "hollandm" <hollandm@pacbell.net>
Subject: AeroElectric-List: Compass shielding
> --> AeroElectric-List message posted by: "hollandm" <hollandm@pacbell.net>
>
> The TC may well be Chinese, who can say these days, but it claims to be
manufactured by mid continent, model 1394T100-7Z.
>
> I haven't been able to scratch up any galvanized tin yet and still
searching for a few square inches of mu-metal.
>
> The electrical separation idea is a no-brainer, unfortunately there are no
available places, within my field of vision where that is possible.
>
> Did try twisting the feed line, no effect.
>
> It is definitely related to the electical field generated by gyro motor
since it only shows an effect on the compass when switched on.
>
>
Message 18
| 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: Compass shielding |
--> AeroElectric-List message posted by: Jerzy Krasinski <krasinski@direcway.com>
Glen Matejcek wrote:
>--> AeroElectric-List message posted by: "Glen Matejcek" <aerobubba@earthlink.net>
>
>Jerzy-
>
>
>
>>Do not bother with shielding the compass, it will not work. The compass
>>MUST be exposed to external magnetic field, this is how it finds
>>directions.
>>
>>
>
>According to my friends in the HUD manufacturing business, your statement about
shielding the compass rendering it useless is incorrect, at least with respect
to mu metal. I suppose this could be different with flashing material, but
IIRC shielding damps dynamic magnetic fields such as EMI, while the earth's magnetic
field is static from the compass' frame of reference. Having said that,
it still makes more sense from the theoretical perspective to shield the antagonist
rather than the victim. Most likely from the practical application perspective,
also.
>
>
>
>
Magnetic compass has a very long time constant. Practically, only static component
of the field can move it. Magnetic compass with high inertia disregards fast
changing fields of EMI no matter if you attenuate them or not.
The magnetic shield attenuates the total magnetic field. The shield can not care
less if the field comes from the Earth or from a current loop. Both components
are attenuated equally.
The compass reacts to the TOTAL static magnetic field, and it can not care less
if the source of the magnetic field is a loop with current or the field of the
Earth. If there was a current loop nearby, the compass would point a wrong direction.
If you put a compass in a thin magnetic shield, you reduce the total field and
make the compass sluggish. For the case where a part of the field comes from a
current loop, the shielding would preserve the ratio of these two fields, and
the compass would still sluggishly point (the same as before) wrong direction.
So in such a case the sluggish compass is even less useful, comparing it to
the case without the shield.
If you put a compass into a thick magnetic shield, you would kill all the external
magnetic field, including the field from the current loop and the field from
the Earth. The compass in a thick shield would be blind, it would have have
no idea about external field and it would point in a random direction. In this
case the compass is totally useless.
Your last comment is correct, but it is not only a theoretical rule, it is very
practical. Practically, it is better to organize a ZOO with wild animals in cages,
while in principle one could make an inverse ZOO with viewers in cages
and free running wild animals.
Jerzy
Message 19
| 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: | Bus Load Analysis |
--> AeroElectric-List message posted by: "Dale Martin" <niceez@cableone.net>
Bob and All,
Bob ask me in a personal response a couple months back if I had done a
system analysis of the new electrical system.
Well, I had not. Compiling all the things that consume power is what began
this quest to update everything.
My question to the group is - what do we consider essential equipment...
Bob had some advise but I did not right it down. Is it possible for us to
compile a few lists for the VFR and the IFR birds from all the great minds
amoung us?
This may have been addressed in the newer updates to the Connection that I
am delinquent in renewing by only 3 years :-(
It would be a good thing to put in the Zeee Options pages :-) (Pun intended)
It has taken two weeks just to trace down a few operating amperages for some
equipment.
Is this reasonable?
Dale Martin
Lewiston, ID
LEZ-235
Message 20
| 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: | Compass shielding |
--> AeroElectric-List message posted by: "Alex Peterson" <alexpeterson@usjet.net>
>
> Did try twisting the feed line, no effect.
>
> It is definitely related to the electical field generated by
> gyro motor since it only shows an effect on the compass when
> switched on.
>
Easiest fix for the magnetic compass is to not look at it. Most planes
have gps, use that. While taxiing out, set the DG to match the gps
track.
Alex Peterson
Maple Grove, MN
RV6-A N66AP 436 hours
www.usfamily.net/web/alexpeterson
Message 21
| 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: | GPS Data port wiring |
--> AeroElectric-List message posted by: Jim Corner <jcorner@shaw.ca>
Gary
I use the RS232 Cable that came with my GPSMAP 295. To connect with the USB
port you may need a cable such as shown at
http://www.gpscity.com/gps/brados/517.1.12685021404219988172/usb4adapter.htm
l and software to match the USB speeds to the RS232 baud rates of your GPS.
Hope this helps
Jim
Hello Learned Listers,
I am trying to put a 9 pin serial connector under my panel for the purpose
of allowing a serial (RS-232) connection that comes out of a GPS (a Garmin
196 in this case) so that a laptop can update its map info.
The laptop only has USB ports (they are both USB version 2.0), so I need to
get a USB-to-RS232 converter cable to make the connection.
Two questions:
1. should the 9 pin connector be male or female, and,
2. should the the tx and rx leads be reversed on the connector, or is that
already done in the USB cable?
If someone has already wired this and could let me know in advance of
getting the cable and installing the 9 pin connector, and doing my own
experiments, I would appreciate it.
Thanks,
Gary Liming
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! --
|