Today's Message Index:
----------------------
1. 07:33 AM - Re: Altitude encoder output voltages (Robert L. Nuckolls, III)
2. 07:34 AM - Re: Re: Premature EarthX death? (Robert L. Nuckolls, III)
3. 07:52 AM - What's all this 'maintainer' stuff anyhow? (Robert L. Nuckolls, III)
4. 07:53 AM - Re: Altitude encoder output voltages (Sebastien)
5. 08:19 AM - Re: Re: Premature EarthX death? (Ken Ryan)
6. 08:20 AM - Re: Re: Premature EarthX death? (Ken Ryan)
7. 08:44 AM - Re: Re: Premature EarthX death? (Robert L. Nuckolls, III)
8. 12:45 PM - Altitude encoder output voltages (Finn Lassen)
9. 12:50 PM - Re: Re: Premature EarthX death? (Ken Ryan)
10. 01:08 PM - Re: Re: Premature EarthX death? (Robert L. Nuckolls, III)
11. 02:06 PM - Re: Re: Premature EarthX death? (Ken Ryan)
12. 03:42 PM - Re: Re: Premature EarthX death? (Robert L. Nuckolls, III)
13. 07:24 PM - Minimum length of fusible link wire segment (Pat Little)
Message 1
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| Subject: | Re: Altitude encoder output voltages |
At 08:21 PM 6/18/2020, you wrote:
>
>I want to make a serial to graycode converter to replace the AK350
>for input to Garmin GTX 320A transponder.
>
>I'd rather have the altitude come from the Dynon D-10A than the
>AK350 -- no discrepancy between what ATC sees and what I see on the
>Dynon (at 29.92 alt setting).
>
>I found the table on
>http://www.aeroelectric.com/articles/Altitude_Encoding/modecascii.txt
>
>I intend to use an Arduino Nano or similar.
>
>But my memory is real vague on the polarity and voltage levels.
>
>Is it correct that the encoder has open-collector outputs and the
>transponder pull-up resistors to system voltage?
>
>Does the transponder expect inverted inputs (0 in table no input and
>1 in table pulling input to ground)?
>
>Finn
Man! That goes back to the dark ages . . . I did some
bench test sets for Cessna/ARC radios waayyy back when
wherein I think outputs from the encoder were
basically open collector with pull-ups in the load.
Hence, the "1" voltage was what ever the load
circuitry provided.
You can't go wrong with open collectors. Lay out
your board to allow adding pull-ups to a 5v rail
should they prove necessary/useful. If I'm all
wet and the polarities are reversed a simple
bit-flip statement will fix it.
Bob . . .
Message 2
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| Subject: | Re: Premature EarthX death? |
At 04:23 PM 6/16/2020, you wrote:
>It was on the bench, heated shop. I should have contacted EarthX but
>I just blamed myself.
>I am sure of the time frame because I had load tested it and made
>notations, and stored those notes with the battery.
>
>Ken
Do you still have the carcass?
Bob . . .
Message 3
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| Subject: | What's all this 'maintainer' stuff anyhow? |
The Battery Tender Jr. (BTJr) saga continued . . .
I let the BTJr recharged battery set for 24+ hours
and this morning I read 12.74 volts open circuit.
Recall that our BTJr charger-maintainer 'relaxed'
to a maintenance level of 13.3V. Okay, I put
the battery on a bench supply set for 13.3 volts.
The test article battery immediately presented
a 'load' of 25mA.
Now, if this value represents the battery's
internal leakage, then one might predict
that the battery would self-discharge to
less than useless in 12000mAh/25mA = 480H
or thereabouts ~ 20 days.
This particular battery is a Orscheln Farm & Home
lawn tractor battery. I think it retails for
about $35 and this particular subject is 3+
years old but kept on the same maintainer that
were using to do the BTJr recharge studies.
I'll leave it on the bench for awhile to see if the
'maintenance' current changes.
The next step is to cap check the battery again
to see how well the BTJr stuffed the energy
back in.
Watch this space . . .
Bob . . .
Message 4
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| Subject: | Re: Altitude encoder output voltages |
How much does an Arduino cost. For about $70 Dynon sells a serial to
greycode converter.
On Fri, Jun 19, 2020, 07:38 Robert L. Nuckolls, III <
nuckolls.bob@aeroelectric.com> wrote:
> At 08:21 PM 6/18/2020, you wrote:
>
> finn.lassen@verizon.net>
>
> I want to make a serial to graycode converter to replace the AK350 for
> input to Garmin GTX 320A transponder.
>
> I'd rather have the altitude come from the Dynon D-10A than the AK350 --
> no discrepancy between what ATC sees and what I see on the Dynon (at 29.92
> alt setting).
>
> I found the table on
> http://www.aeroelectric.com/articles/Altitude_Encoding/modecascii.txt
>
> I intend to use an Arduino Nano or similar.
>
> But my memory is real vague on the polarity and voltage levels.
>
> Is it correct that the encoder has open-collector outputs and the
> transponder pull-up resistors to system voltage?
>
> Does the transponder expect inverted inputs (0 in table no input and 1 in
> table pulling input to ground)?
>
> Finn
>
>
> Man! That goes back to the dark ages . . . I did some
> bench test sets for Cessna/ARC radios waayyy back when
> wherein I think outputs from the encoder were
> basically open collector with pull-ups in the load.
> Hence, the "1" voltage was what ever the load
> circuitry provided.
>
> You can't go wrong with open collectors. Lay out
> your board to allow adding pull-ups to a 5v rail
> should they prove necessary/useful. If I'm all
> wet and the polarities are reversed a simple
> bit-flip statement will fix it.
>
>
> Bob . . .
>
Message 5
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| Subject: | Re: Premature EarthX death? |
No, sorry Bob. I used to ride motorcycles and it was not unusual that I
would trash a battery letting it sit over the winter. So my mindset was
that it must have been my fault (again) so I just got rid of it and bought
a new one, vowing to keep it on the maintainer.
On Fri, Jun 19, 2020 at 6:40 AM Robert L. Nuckolls, III <
nuckolls.bob@aeroelectric.com> wrote:
> At 04:23 PM 6/16/2020, you wrote:
>
> It was on the bench, heated shop. I should have contacted EarthX but I
> just blamed myself.
> I am sure of the time frame because I had load tested it and made
> notations, and stored those notes with the battery.
>
> Ken
>
>
> Do you still have the carcass?
>
> Bob . . .
>
Message 6
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| Subject: | Re: Premature EarthX death? |
This was a number of years ago, before the model with the dual bms and
warning light lead. I don't remember whether or not that model's bms was
supposed to protect it from over discharge.
On Fri, Jun 19, 2020 at 7:13 AM Ken Ryan <keninalaska@gmail.com> wrote:
> No, sorry Bob. I used to ride motorcycles and it was not unusual that I
> would trash a battery letting it sit over the winter. So my mindset was
> that it must have been my fault (again) so I just got rid of it and bought
> a new one, vowing to keep it on the maintainer.
>
>
> On Fri, Jun 19, 2020 at 6:40 AM Robert L. Nuckolls, III <
> nuckolls.bob@aeroelectric.com> wrote:
>
>> At 04:23 PM 6/16/2020, you wrote:
>>
>> It was on the bench, heated shop. I should have contacted EarthX but I
>> just blamed myself.
>> I am sure of the time frame because I had load tested it and made
>> notations, and stored those notes with the battery.
>>
>> Ken
>>
>>
>> Do you still have the carcass?
>>
>> Bob . . .
>>
>
Message 7
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| Subject: | Re: Premature EarthX death? |
At 10:16 AM 6/19/2020, you wrote:
>This was a number of years ago, before the model
>with the dual bms and warning light lead. I
>don't remember whether or not that model's bms
>was supposed to protect it from over discharge.=C2
I believe their bms always protected from over discharge
but it could not protect against self discharge. For example,
a battery that has been 'protected' due to very low state
of charge still needs to be recharged asap. Just because
it has protected itself from external discharge, it cannot
stand of effects of internal discharge. This MIGHT be what
happened to yours.
Bob . . .
Message 8
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| Subject: | Altitude encoder output voltages |
Half of the emails from the Matronics list server ends up AOL spam
filter. Several don't make it at all. Got this using the list browser:
"How much does an Arduino cost. For about $70 Dynon sells a serial to
greycode converter."
I ordered three Nanos for $6. May take some weeks to get them.
I have 74LS05 hex drivers and PC boards laying around.
Then there's the fun of DYI.
Then there's the fact that I can program it to accept any of the inputs
from the D-10A.
Not really needed, but there's plenty of space in a Nano for a table up
to 67,000' or higher.
Here's another question.
There are several serial altitude formats:
Format 1
Used By
Dynon Encoder Serial-to-Parallel Converter, Garmin AT (formerly UPS
Aviation Technologies)
Baud rate
1200
Format
#AL, space, +/-sign, five altitude bytes, T+25, checksum, carriage return
Example message
#AL +05200T+25D7[CR]
Format 2
Used By
Magellan
Baud rate
1200
Format
$MGL, +/- sign, five altitude digits, T+25, checksum, carriage return
Example message
$MGL+05200T+25E3[CR]
Format 3
Used By
Northstar, Garmin
Baud rate
2400
Format
ALT, space, five altitude bytes, carriage return
Example message
ALT 05200[CR]
Format 4
Used By
Garmin GTX330 (set on Icarus input), Garmin GTX327 (set on Icarus
input), Garmin GTX328, Icarus, Trimble
Baud rate
9600
Format
ALT, space, five altitude bytes, carriage return
Example message
ALT 05200[CR]
Format 3 and 4 apparently do not have an altitude +/- sign.
So, what happens when you're below 0' pressure altitude?
Gray codes go down to -1200'
Do they reason that if you're flying that low there's no radar coverage
anyway?
Finn
----------------------------------------------------------------------
I want to make a serial to graycode converter to replace the AK350 for
input to Garmin GTX 320A transponder.
I'd rather have the altitude come from the Dynon D-10A than the AK350 --
no discrepancy between what ATC sees and what I see on the Dynon (at
29.92 alt setting).
I found the table on
http://www.aeroelectric.com/articles/Altitude_Encoding/modecascii.txt
I intend to use an Arduino Nano or similar.
But my memory is real vague on the polarity and voltage levels.
Is it correct that the encoder has open-collector outputs and the
transponder pull-up resistors to system voltage?
Does the transponder expect inverted inputs (0 in table no input and 1
in table pulling input to ground)?
Finn
Message 9
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| Subject: | Re: Premature EarthX death? |
Thanks Bob. Now that you have pointed it out, it seems obvious that the BMS
could never protect from self-discharge!
Ken
On Fri, Jun 19, 2020 at 7:50 AM Robert L. Nuckolls, III <
nuckolls.bob@aeroelectric.com> wrote:
> At 10:16 AM 6/19/2020, you wrote:
>
> This was a number of years ago, before the model with the dual bms and
> warning light lead. I don't remember whether or not that model's bms was
> supposed to protect it from over discharge.=C3=82
>
>
> I believe their bms always protected from over discharge
> but it could not protect against self discharge. For example,
> a battery that has been 'protected' due to very low state
> of charge still needs to be recharged asap. Just because
> it has protected itself from external discharge, it cannot
> stand of effects of internal discharge. This MIGHT be what
> happened to yours.
>
>
> Bob . . .
>
Message 10
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| Subject: | Re: Premature EarthX death? |
At 02:19 PM 6/19/2020, you wrote:
>Thanks Bob. Now that you have pointed it out, it seems obvious that
>the BMS could never protect from self-discharge!
>
>Ken
How long had the battery been in
satisfactory service before it when
t.u.?
Bob . . .
Message 11
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| Subject: | Re: Premature EarthX death? |
It was never in service. It was for an unfinished project. It was about two
or three years old, I think. It had been charged periodically during the
first couple of years using EarthX recommended charger. Then at about 2 or
3 years old I finally developed a load test system and so I did a load
test. I no longer have that record, but it tested as expected. Then I
charged it back up and it sat for a year. That's when it was dead. I
suppose it is possible that I did not charge it after the load test. But at
the price of those things and having previous experience failing motorcycle
batteries, that seems unlikely.
On Fri, Jun 19, 2020 at 12:14 PM Robert L. Nuckolls, III <
nuckolls.bob@aeroelectric.com> wrote:
> At 02:19 PM 6/19/2020, you wrote:
>
> Thanks Bob. Now that you have pointed it out, it seems obvious that the
> BMS could never protect from self-discharge!
>
> Ken
>
>
> How long had the battery been in
> satisfactory service before it when
> t.u.?
>
>
> Bob . . .
>
Message 12
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| Subject: | Re: Premature EarthX death? |
At 03:26 PM 6/19/2020, you wrote:
>It was never in service. It was for an
>unfinished project. It was about two or three
>years old, I think. It had been charged
>periodically during the first couple of=C2 years
>using EarthX recommended charger. Then at about
>2 or 3 years old I finally developed a load test
>system and so I did a load test. I no longer
>have that record, but it tested as expected.
>Then I charged it back up and it sat for a year.
>That's when it was dead. I suppose it is
>possible that I did not charge it after the load
>test. But at the price of those things and
>having previous experience failing motorcycle batteries, that seems
unlikely.
bummer . . .
for years at my seminars I suggested
that builders don't buy a battery until
a few weeks before first flight. 'til then
you can test with some jury-rigged car
battery.
I think I made that suggestion the first
time when an attendee stated that he was
going to 'cruise the booths at OSH next
month to see if he could snag a good deal
on a battery.' He asked for recommendations.
He admitted being years away from flying.
That was before lithium . . . also very
early in evolution of AGM products. I
suggested he would be money and risk ahead
with a 'fresh' battery in his newly minted
airplane. I think that advice still holds water.
Bob . . .
Message 13
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| Subject: | Minimum length of fusible link wire segment |
Bob, in a recent post you state that there is a 9-inch rule of thumb
minimum length for fusible link wire segments. Could you explain the
physics behind that, please?
Pat
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