Today's Message Index:
----------------------
1. 09:32 AM - Re: Re: Poor Man's Battery Tester (Robert L. Nuckolls, III)
2. 09:37 AM - Re: EFIS Erratic Temp Readings (Robert L. Nuckolls, III)
3. 12:54 PM - Re: EFIS Erratic Temp Readings ()
4. 02:34 PM - Re: EFIS Erratic Temp Readings (Robert L. Nuckolls, III)
5. 04:38 PM - Re: EFIS Erratic Temp Readings (Charlie England)
Message 1
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| Subject: | Re: Poor Man's Battery Tester |
At 03:41 PM 2/3/2021, you wrote:
>
>XH-M609 Battery Low Voltage Disconnect Module is available on eBay
>for as little as $5.
>Let me know if there is an error in my circuit.
>
>--------
>Joe Gores
Looks good to me Joe. You could also use
two FORWARD biased diodes to get your ~1.5
Volt supply for the clock. Let us know how
this shakes out . . .
Bob . . .
Un impeachable logic: George Carlin asked, "If black boxes
survive crashes, why don't they make the whole airplane
out of that stuff?"
Message 2
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| Subject: | EFIS Erratic Temp Readings |
At 11:51 PM 2/1/2021, you wrote:
>If I only have sensor connected temperature
>reading is different for each =9Cscan=9D and
>varies by up to 150 degrees between max and min.
>
>If I connect more sensors readings become more
>and more erratic. Even if no sensors are
>connected =9Cghost=9D readings appear for
>cylinders not connected with the same reading
>for EGT and CHT. Ghost readings vary from between -50 to 800 degrees.
>
>
>Hope that helps
Mike, I was reviewing this thread and another
thought occurs. While testing with 'no sensors'
what was the condition of the open inputs?
Did you put shorts across them or were they
simply disconnected?
Bob . . .
Un impeachable logic: George Carlin asked, "If black boxes
survive crashes, why don't they make the whole airplane
out of that stuff?"
Message 3
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| Subject: | EFIS Erratic Temp Readings |
From: owner-aeroelectric-list-server@matronics.com
<owner-aeroelectric-list-server@matronics.com> On Behalf Of Robert L.
Nuckolls, III
Sent: February 6, 2021 9:36 AM
Subject: RE: AeroElectric-List: EFIS Erratic Temp Readings
At 11:51 PM 2/1/2021, you wrote:
Mike, I was reviewing this thread and another
thought occurs. While testing with 'no sensors'
what was the condition of the open inputs?
Did you put shorts across them or were they
simply disconnected?
No, they were not shorted, simply disconnected. Will try
with them shorted next week.
I would never have thought of shorting them
I did remove the alternator and ran the engine with no
alternator and that made no difference,
Readings were still erratic
Thanks
Mike
Bob . . .
Un impeachable logic: George Carlin asked, "If black boxes
survive crashes, why don't they make the whole airplane
out of that stuff?"
Message 4
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| Subject: | EFIS Erratic Temp Readings |
> No, they were not shorted, simply disconnected.
> Will try with them shorted next week.
>
> I would never have thought of shorting them
It used to be pretty much standard that
the input to a thermocouple driven display
device was pretty low impedance. Modern
electronics allows us to resolve those
tiny voltages with displays having very
high input impedances.
I have data acquisition equipment that
requires unused channels to be 'tied down',
i.e. shorted out. Otherwise they 'wander'
in response to stimuli in the environment.
Your EFIS may be similarly designed.
>
>
> I did remove the alternator and ran the engine with
> no alternator and that made no difference,
>
> Readings were still erratic
Hmmmm . . . so probably no value in exploring
noise on the DC power line.
See what the thing does with all inputs 'locked
down' . . . then if stable . . . try adding one
t/c at a time.
Bob . . .
Un impeachable logic: George Carlin asked, "If black boxes
survive crashes, why don't they make the whole airplane
out of that stuff?"
Message 5
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| Subject: | Re: EFIS Erratic Temp Readings |
snipped
>
>
> Did you put shorts across them or were they
> simply disconnected?
>
> No, they were not shorted, simply disconnected. Will
> try with them shorted next week.
>
> I would never have thought of shorting them
>
> I did remove the alternator and ran the engine with no
> alternator and that made no difference,
>
> Readings were still erratic
>
> Thanks
>
> Mike
>
Hi Mike,
Can you remind us whether the engine is 'standard' mags & carb (or
Bendix style injection), or if it has some combination of electronic
ignition/fuel injection?
Thanks,
Charlie
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