Today's Message Index:
----------------------
1. 12:15 PM - Brass is not a very good conductor (rparigor@SUFFOLK.LIB.NY.US)
2. 12:48 PM - EI Altitude Clock Mod (Don Curry)
3. 01:31 PM - EI SC-5 clock doc error (Ron Shannon)
4. 05:13 PM - Re: EI Altitude Clock Mod (Ed Anderson)
5. 05:33 PM - Re: EI Altitude Clock Mod (currydon@bellsouth.net)
6. 05:33 PM - Re: Brass is not a very good conductor (Vern Little)
7. 05:44 PM - Re: EI SC-5 clock doc error (JAMES BOWEN)
8. 07:14 PM - Thanks for Twisted Pair Answers (Dennis Johnson)
9. 07:36 PM - Re: EI Altitude Clock Mod (S. Ramirez)
10. 07:47 PM - Re: EI SC-5 clock doc error (Greg Young)
Message 1
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Subject: | Brass is not a very good conductor |
Figured would share with the group at just how poor a conductor brass is.
According to:
http://www.kp44.org/ftp/ElectricalConductivityOfMaterials.php
Brass only has ~ 28% the conductivity of copper. (They don't get as
specific as alloy types)
I need to somehow wire my port headrest (negative) to my starboard
headrest. Shortest distance is direct between headrests but using a
traditional wire will be unsightly and make for harder interior install.
It needs to carry enough current to allow an occasional jump start.
Since Ace hardware sells .032" thick brass 1" wide (alloy 260), I was
going to use that and trim it to .75" wide until I researched just how
poor a conductor brass is. Could double the thickness and double the
width, but that would make for more weight and harder interior install.
Anyway, going to use .75" wide by .032" thick copper alloy 110 and glass
it in place with one thin layer of 3/4 oz model aeroplane cloth.
Ron Parigoris
Message 2
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Subject: | EI Altitude Clock Mod |
Ok all you electronics warriors out there, here's a good one:
Electronics
International designed and markets a pretty nifty-looking aircraft clock
called the ASC-5A. One of the nifty things about it is that it is more
than
just a clock - it's also an altitude alerter. Put in your MDA and your
speed-based approach time, and you'll get an LED indication on the face
of
the instrument telling you that you have arrived either at your altitude
or
your time. It even has an external-warning capability that, when paired
with a tone or voice generator, can send alerts to your headset. But
here's
the rub: it only has ONE external-warning wire, so regardless of whether
it
is a timer alert or an altitude alert, it goes out over this one wire
(and
in the same way, probably as a ground). As a result, when your headset
alert sounds on a VOR approach, you must obtain additional input (i.e.,
you
need to look at the face of the clock or your altimeter) to determine
whether it is because you have reached the MDA and you need to level off
or
because you have exhausted your time and need to execute a missed
approach.
So, internally the unit can differentiate between altitude events and
timer
events because it lights different LEDs on the face of the instrument
for
these different events, but EI didn't extend that basic capability to
the
external-warning feature sticking out the back of the instrument. What
were
they thinking? At this point, it seems like a simple matter to tap into
the
light circuits that activate the LEDs on the front of the instrument,
extend
some wires from those taps out the back, hook up a tone or voice
generator,
and receive separate signals in your headset for time and altitude
alerts.
But I don't want to open mine up without first getting some feedback.
Ok, I
soldered once and it didn't turn out well, so I'm reluctant to tear into
my
~$500 instrument without lots of encouragement (I've learned that things
that begin with, "Honey, watch this!" often don't turn out well. . .)!
Any
thoughts?
Thanks,
Don
Message 3
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Subject: | EI SC-5 clock doc error |
The previous post inspired me to share this recent discovery.
The EI SC-5 clock includes a non-resettable total engine time counter,
essentially a Hobbes function. The manual says that in a 12V system, the
ORANGE wire should be connected via an N.O. oil pressure switch to provide
+12V on closure, when oil pressure develops, which will start the engine
timer. This is a little tricky with the B&P oil presure switch, where the
N.O. contact is normally grounded -- I even set up a little relay to power
the wire that way -- but don't bother. Contrary to the manual, any time the
RED +12V main supply wire is hot, the engine timer runs, regardless of
what's is or isn't happening on the ORANGE wire. For example, if you're
running the panel on ground power, perhaps for training or maintenance, or
just entering a flight plan into the GPS before engine start, the engine
timer will be ticking up, even though the engine isn't running. (The clock
is supposed to be wired to a main bus or e-bus, so it's going to be ON when
most anything on the panel is on.) Incidentally, the manual also says that
in a 12V system, the BROWN wire should _not_ be connected to anything.
After considerable consultation with EI, it was confirmed that the ORANGE
wire is at best superfluous to the engine timer function (or any function as
far as I could determine) and the BROWN wire is what must be used to control
the engine timer. The BROWN wire should be grounded when the engine is OFF,
i.e., wired through a N.C. contact on a B&C pressure switch, in parallel
with the oil pressure warning light. When the BROWN wire's connection to
ground is broken, on engine start, the engine timer begins.
So, what the manual says to do doesn't work, and what the manual says not to
do is what you have to do to make it work. I suggested to EI that they
should at least fix the manual, but they did not indicate any eagerness to
do so. Hopefully, this work around will be useful others.
Otherwise, it's a nice clock.
Ron
Message 4
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Subject: | EI Altitude Clock Mod |
In electronics all things are possible, Don (well, almost {:>)).
The feasibility of doing what you suggest is certainly conceptually simple;
however, it depends quite a bit on what format the electronics have taken.
If there are isolated wires running from a board to a couple of LED holders
then that would probably be fairly simply provided you take care not to
overload load the LED circuit. I would put in some sort of isolation
barrier - such as an Ops amp - perhaps an Ops amp circuit with a tone
generator designed in.
However, if the LED's are an integrated part of a printed circuit board -
then while still conceptually feasible, you need someone who knows how to
modify a board (probably with surface mount components) - a person with the
right skills and experience could do it - but, where do you find him? I
certainly would hesitate to let just anyone wearing a hat with a lightening
bolt through it tackle it.
If you can do it without damage to the unit, you might open it up and take a
peek. If it looks like wires to the LEDs, then you might consider
proceeding further - if it looks like the LED's are an integrated part of a
print circuit board, I think I would just button it back up.
I agree with you that one would have thought the designer/manufacture would
have considered the advantages of a dual audio alarm.
Good luck
Ed
Ed Anderson
Rv-6A N494BW Rotary Powered
Matthews, NC
eanderson@carolina.rr.com
<http://www.andersonee.com/> http://www.andersonee.com
<http://members.cox.net/rogersda/rotary/configs.htm>
http://members.cox.net/rogersda/rotary/configs.htm#N494BW
<http://www.dmack.net/mazda/index.html>
http://www.dmack.net/mazda/index.html
_____
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Don Curry
Sent: Tuesday, December 30, 2008 3:45 PM
Subject: AeroElectric-List: EI Altitude Clock Mod
Ok all you electronics warriors out there, here's a good one: Electronics
International designed and markets a pretty nifty-looking aircraft clock
called the ASC-5A. One of the nifty things about it is that it is more than
just a clock - it's also an altitude alerter. Put in your MDA and your
speed-based approach time, and you'll get an LED indication on the face of
the instrument telling you that you have arrived either at your altitude or
your time. It even has an external-warning capability that, when paired
with a tone or voice generator, can send alerts to your headset. But here's
the rub: it only has ONE external-warning wire, so regardless of whether it
is a timer alert or an altitude alert, it goes out over this one wire (and
in the same way, probably as a ground). As a result, when your headset
alert sounds on a VOR approach, you must obtain additional input (i.e., you
need to look at the face of the clock or your altimeter) to determine
whether it is because you have reached the MDA and you need to level off or
because you have exhausted your time and need to execute a missed approach.
So, internally the unit can differentiate between altitude events and timer
events because it lights different LEDs on the face of the instrument for
these different events, but EI didn't extend that basic capability to the
external-warning feature sticking out the back of the instrument. What were
they thinking? At this point, it seems like a simple matter to tap into the
light circuits that activate the LEDs on the front of the instrument, extend
some wires from those taps out the back, hook up a tone or voice generator,
and receive separate signals in your headset for time and altitude alerts.
But I don't want to open mine up without first getting some feedback. Ok, I
soldered once and it didn't turn out well, so I'm reluctant to tear into my
~$500 instrument without lots of encouragement (I've learned that things
that begin with, "Honey, watch this!" often don't turn out well. . .)! Any
thoughts?
Thanks,
Don
__________ Information from ESET NOD32 Antivirus, version of virus signature
database 3267 (20080714) __________
The message was checked by ESET NOD32 Antivirus.
Message 5
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Subject: | EI Altitude Clock Mod |
Message 6
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Subject: | Re: Brass is not a very good conductor |
Ron, there has been some discussion on this in the past, and there were
questions about sourcing copper bus bar material.
Van's Aircraft sells bass strips for this purpose, or you can flatten a
copper pipe and use it.
I replaced the brass buss-bars on my RV-9A prior to completion after doing a
voltage drop analysis through the system.
Probably would not make a significant difference, but if you have a choice,
use copper.
Vern Little
Vx Aviation
www.vx-aviation.com
----- Original Message -----
From: <rparigor@SUFFOLK.LIB.NY.US>
Sent: Tuesday, December 30, 2008 12:09 PM
Subject: AeroElectric-List: Brass is not a very good conductor
Figured would share with the group at just how poor a conductor brass is.
According to:
http://www.kp44.org/ftp/ElectricalConductivityOfMaterials.php
Brass only has ~ 28% the conductivity of copper. (They don't get as
specific as alloy types)
I need to somehow wire my port headrest (negative) to my starboard
headrest. Shortest distance is direct between headrests but using a
traditional wire will be unsightly and make for harder interior install.
It needs to carry enough current to allow an occasional jump start.
Since Ace hardware sells .032" thick brass 1" wide (alloy 260), I was
going to use that and trim it to .75" wide until I researched just how
poor a conductor brass is. Could double the thickness and double the
width, but that would make for more weight and harder interior install.
Anyway, going to use .75" wide by .032" thick copper alloy 110 and glass
it in place with one thin layer of 3/4 oz model aeroplane cloth.
Ron Parigoris
Message 7
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Subject: | EI SC-5 clock doc error |
THANK YOU. I AM INSTALLING THAT SAME CLOCK AS WE SPEAK. MUCH APPRECIATED!
JIM BOWEN
ectric-list@matronics.comSubject: AeroElectric-List: EI SC-5 clock doc erro
rThe previous post inspired me to share this recent discovery.The EI SC-5 c
lock includes a non-resettable total engine time counter=2C essentially a H
obbes function. The manual says that in a 12V system=2C the ORANGE wire sho
uld be connected via an N.O. oil pressure switch to provide +12V on closure
=2C when oil pressure develops=2C which will start the engine timer. This i
s a little tricky with the B&P oil presure switch=2C where the N.O. contact
is normally grounded -- I even set up a little relay to power the wire tha
t way -- but don't bother. Contrary to the manual=2C any time the RED +12V
main supply wire is hot=2C the engine timer runs=2C regardless of what's is
or isn't happening on the ORANGE wire. For example=2C if you're running th
e panel on ground power=2C perhaps for training or maintenance=2C or just e
ntering a flight plan into the GPS before engine start=2C the engine timer
will be ticking up=2C even though the engine isn't running. (The clock is s
upposed to be wired to a main bus or e-bus=2C so it's going to be ON when m
ost anything on the panel is on.) Incidentally=2C the manual also says that
in a 12V system=2C the BROWN wire should _not_ be connected to anything.Af
ter considerable consultation with EI=2C it was confirmed that the ORANGE w
ire is at best superfluous to the engine timer function (or any function as
far as I could determine) and the BROWN wire is what must be used to contr
ol the engine timer. The BROWN wire should be grounded when the engine is O
FF=2C i.e.=2C wired through a N.C. contact on a B&C pressure switch=2C in p
arallel with the oil pressure warning light. When the BROWN wire's connecti
on to ground is broken=2C on engine start=2C the engine timer begins.So=2C
what the manual says to do doesn't work=2C and what the manual says not to
do is what you have to do to make it work. I suggested to EI that they shou
ld at least fix the manual=2C but they did not indicate any eagerness to do
so. Hopefully=2C this work around will be useful others.Otherwise=2C it's
a nice clock.Ron
Message 8
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Subject: | Thanks for Twisted Pair Answers |
Thanks to Bob, Simon, and others for your great answers to my question
about twisted pair vs. parallel wires. If I keep asking questions and
you guys keep giving such well-reasoned answers, some day I might
actually understand this stuff.
Thanks,
Dennis
do not archive
Message 9
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Subject: | EI Altitude Clock Mod |
Don, I looked at the ASC-5A Operating Instructions and saw a picture of its
front panel. I am willing to bet that all of those LEDs, the LCD and the
switches are connected directly to a printed circuit board. You can verify
this for us by opening the unit and looking at it. Obviously, you do this
at your own risk.
Regardless of whether they are connected by wire or printed circuit board,
you can connect to these LEDs by wire. All you have to do is solder wires
to the solder points. I'd suggest that you have this done by a person known
as an "assembler" in the electronics world. I've seen too many engineers
who think they know how to solder, only to destroy a board by applying too
much heat, too little heat, too much solder, not cleaning flux off the
board, etc. A poor solder job usually results in a failure in our vibration
environment.
Typically, an LED will be turned on by a driver going low at its cathode.
This causes it to sink current through the LED. The LED's anode is
connected to the voltage source through a current limiting resistor. When
the LED is turned off, the driver will be in the tri-state mode, thus
causing only leakage current to flow through the LED. Therefore, when
turned on, the LED's cathode will be low, and when turned off, the LED's
cathode will be high. What "low" and "high" is depends on the driver and
voltage source used.
Since a low most likely is the active state (you can verify this), it is not
good enough by itself to generate a tone. This means that you will use it
as a gating signal to generate such a tone. Someone earlier suggested that
you will have to use op amps to isolate these two signals so that they don't
interfere with the LEDs' operation. I would suggest keeping it in the
digital world and using an appropriate driver that also has a high input
impedance. In either case, you are now faced with bringing out one or two
ground wire(s) with these two wires and running all wires to wherever you
are taking them to, because you will need a reference ground where you are
going. I will suggest that you write me directly after you find out what's
inside your ASC-5A if you are really serious about this project. There are
several details that need to be known to find the best course of action, and
only the owner can determine these details.
Simon Ramirez
Copyright 2008
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Don Curry
Sent: Tuesday, December 30, 2008 3:45 PM
Subject: AeroElectric-List: EI Altitude Clock Mod
Ok all you electronics warriors out there, here's a good one: Electronics
International designed and markets a pretty nifty-looking aircraft clock
called the ASC-5A. One of the nifty things about it is that it is more than
just a clock - it's also an altitude alerter. Put in your MDA and your
speed-based approach time, and you'll get an LED indication on the face of
the instrument telling you that you have arrived either at your altitude or
your time. It even has an external-warning capability that, when paired
with a tone or voice generator, can send alerts to your headset. But here's
the rub: it only has ONE external-warning wire, so regardless of whether it
is a timer alert or an altitude alert, it goes out over this one wire (and
in the same way, probably as a ground). As a result, when your headset
alert sounds on a VOR approach, you must obtain additional input (i.e., you
need to look at the face of the clock or your altimeter) to determine
whether it is because you have reached the MDA and you need to level off or
because you have exhausted your time and need to execute a missed approach.
So, internally the unit can differentiate between altitude events and timer
events because it lights different LEDs on the face of the instrument for
these different events, but EI didn't extend that basic capability to the
external-warning feature sticking out the back of the instrument. What were
they thinking? At this point, it seems like a simple matter to tap into the
light circuits that activate the LEDs on the front of the instrument, extend
some wires from those taps out the back, hook up a tone or voice generator,
and receive separate signals in your headset for time and altitude alerts.
But I don't want to open mine up without first getting some feedback. Ok, I
soldered once and it didn't turn out well, so I'm reluctant to tear into my
~$500 instrument without lots of encouragement (I've learned that things
that begin with, "Honey, watch this!" often don't turn out well. . .)! Any
thoughts?
Thanks,
Don
Message 10
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Subject: | EI SC-5 clock doc error |
Same here. I've got one on the bench waiting on a convenient time to
install. Good and very timely info. Thanks.
Regards,
Greg Young
_____
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of JAMES
BOWEN
Sent: Tuesday, December 30, 2008 7:41 PM
Subject: RE: AeroElectric-List: EI SC-5 clock doc error
THANK YOU. I AM INSTALLING THAT SAME CLOCK AS WE SPEAK. MUCH APPRECIATED!
JIM BOWEN
_____
From: rshannon@CRUZCOM.COM
Subject: AeroElectric-List: EI SC-5 clock doc error
The previous post inspired me to share this recent discovery.
The EI SC-5 clock includes a non-resettable total engine time counter,
essentially a Hobbes function. The manual says that in a 12V system, the
ORANGE wire should be connected via an N.O. oil pressure switch to provide
+12V on closure, when oil pressure develops, which will start the engine
timer. This is a little tricky with the B&P oil presure switch, where the
N.O. contact is normally grounded -- I even set up a little relay to power
the wire that way -- but don't bother. Contrary to the manual, any time the
RED +12V main supply wire is hot, the engine timer runs, regardless of
what's is or isn't happening on the ORANGE wire. For example, if you're
running the panel on ground power, perhaps for training or maintenance, or
just entering a flight plan into the GPS before engine start, the engine
timer will be ticking up, even though the engine isn't running. (The clock
is supposed to be wired to a main bus or e-bus, so it's going to be ON when
most anything on the panel is on.) Incidentally, the manual also says that
in a 12V system, the BROWN wire should _not_ be connected to anything.
After considerable consultation with EI, it was confirmed that the ORANGE
wire is at best superfluous to the engine timer function (or any function as
far as I could determine) and the BROWN wire is what must be used to control
the engine timer. The BROWN wire should be grounded when the engine is OFF,
i.e., wired through a N.C. contact on a B&C pressure switch, in parallel
with the oil pressure warning light. When the BROWN wire's connection to
ground is broken, on engine start, the engine timer begins.
So, what the manual says to do doesn't work, and what the manual says not to
do is what you have to do to make it work. I suggested to EI that they
should at least fix the manual, but they did not indicate any eagerness to
do so. Hopefully, this work around will be useful others.
Otherwise, it's a nice clock.
Ron
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