Today's Message Index:
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1. 10:11 AM - Electronic Ignition spark advance signal boost (Airdog77)
2. 05:22 PM - Radiated Electronic Noise (not a grounding issue?) (Noel Wade)
3. 07:06 PM - Re: Electronic Ignition spark advance signal boost (C&K)
4. 08:33 PM - Re: Electronic Ignition spark advance signal boost (Airdog77)
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Subject: | Electronic Ignition spark advance signal boost |
Hi All,
I have yet another issue I was hoping the gurus here on the list could help me
figure out.
I have an Electroair electronic ignition system that has a wire coming out of the
unit's controller for a spark advance meter. Electroair (nor their customers
apparently) hasn't used this wire or a meter in ages, so it's a rather dormant
feature, although it does still put out an active (albeit optional) signal
to show the set spark advance BTDC.
I would like to attach this Electroair spark advance wire to an Auxiliary port
on my GRT EIS4000 engine management system to then show the spark advance on my
EFIS. However, the issue I'm running into is the spark advance signal output,
the voltage range of which may prove too low for the GRT EIS to read reliably
(as per GRT).
The Electroair spark advance signal voltage output is from 0.00V to 0.40V, and
is scaled 0.01 volt per every degree of advance. So just to be clear:
0.01V = 1 degree of advance
0.10V = 10 degrees of advance
0.28V = 28 degrees of advance
What I would like to achieve is to amplify the spark advance signal voltage x 10
so that the GRT could see every 0.1V as 1 degree of spark advance, so again
for clarity:
0.1V = 1 degree of advance
1.0V = 10 degrees of advance
2.8V = 28 degrees of advance
Since the original spark advance signal is on a range of 0 to 0.4 volts, if I amped
it up x10 then my max output would be 4.0 volts, still well under the 5.0V
max input of the GRT EIS auxiliary ports.
Regards,
Wade
--------
Airdog
Wade Parton
Building Long-EZ N916WP
www.longezpush.com
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=476445#476445
Message 2
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Subject: | Radiated Electronic Noise (not a grounding issue?) |
Hello All,
I'm hoping for suggestions from the experts here, as I'm stumped at how I
might alleviate a problem with what I think is *radiated* EMI that's making
its way from my EFIS into my VHF radio system (i.e. over the air, received
by the comm antenna). And so far the manufacturer has been unresponsive to
my support requests. :-(
Here is a video demonstration of the issue, using a handheld radio (to try
to show that this is not a ground-loop or other issue with the wiring of
the panel-mounted VHF comm system):
https://www.youtube.com/watch?v=kg8bZ5wZ3bk
After recording that video, I tried placing a piece of sheet-metal in front
of the antenna (to block line-of-sight from the EFIS) with the sheet-metal
grounded to the airframe. I can clearly demonstrate a change in the amount
of received signal when the sheet-metal is removed from blocking LOS, by
observing the reception-strength bargraph built into the VHF radio. This to
me reinforces the idea that this is some kind of electromagnetic
field/radiation that's the problem, not induction along a wiring path. But
I'll admit that I'm a novice when it comes to EE stuff; I usually work in
the digital realm with computers and networking, far from oscilloscopes and
the analog world of volts and amps.
Any thoughts or recommendations for how to proceed, how this issue might be
confirmed, and/or how it could be alleviated, short of replacing the
system**?
Thanks so much for your knowledge and ideas!
--Noel Wade
noel.wade@gmail.com
Seattle, WA
-----
Background info, for the interested:
-----
I _can_ run the squelch up very high in order to not have the panel-mounted
VHF radio think its receiving a valid signal. But that severely limits my
reception range overall. I've done testing with various items in the
aircraft powered off (and with fuses removed), and the problem only occurs
when my EFIS is powered on - as evidenced in the video. And again, this
issue occurs with handhelds as well as the panel-mounted radio.
To be clear: This is *not* an issue with noise or feedback in the headset.
This is the radio actually thinking its receiving a signal and breaking
squelch. The panel-mounted radio was previously used in my sailplane and
worked just fine (at a much lower squelch value). And it works just fine at
a low squelch value with other aircraft items powered on and the EFIS
"cold". Other aircraft on the ground at my local airport report my radio
transmissions as loud-and-clear, so outbound transmissions seem unaffected.
For power and ground, all equipment in my panel is wired in using twisted
twisted pairs: Each supply line comes from a fuse block, and each ground
wire goes to a "forest of tabs" on the stainless steel firewall with a
large-gauge wire connected back to the battery. Signal wires are almost
exclusively run through wiring harnesses provided by the manufacturer,
using shielded wires and a twisted-pair CAN bus wire or RS-232 signals
(again on a shielded wiring pair). The comm antenna is connected to the
radio using RG-400 coax and the coax is run at least 6" away from the
(shielded) headset and microphone wires.
Photos of my aircraft build (including some shots of the wiring) are here:
https://flic.kr/s/aHskrtEG22
-----
Message 3
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Subject: | Re: Electronic Ignition spark advance signal boost |
Wade
If you google "non inverting op amp" you should find a simple voltage
multiplier circuit that you can power with the EIS 5 volt sensor supply.
Pretty much any 8 pin op amp and a couple of resistors to set the gain
at 10 will do this nicely.
Ken
On 16/12/2017 1:11 PM, Airdog77 wrote:
>
> Hi All,
>
> I have yet another issue I was hoping the gurus here on the list could help me
figure out.
>
> I have an Electroair electronic ignition system that has a wire coming out of
the unit's controller for a spark advance meter. Electroair (nor their customers
apparently) hasn't used this wire or a meter in ages, so it's a rather dormant
feature, although it does still put out an active (albeit optional) signal
to show the set spark advance BTDC.
>
> I would like to attach this Electroair spark advance wire to an Auxiliary port
on my GRT EIS4000 engine management system to then show the spark advance on
my EFIS. However, the issue I'm running into is the spark advance signal output,
the voltage range of which may prove too low for the GRT EIS to read reliably
(as per GRT).
>
> The Electroair spark advance signal voltage output is from 0.00V to 0.40V, and
is scaled 0.01 volt per every degree of advance. So just to be clear:
> 0.01V = 1 degree of advance
> 0.10V = 10 degrees of advance
> 0.28V = 28 degrees of advance
>
> What I would like to achieve is to amplify the spark advance signal voltage x
10 so that the GRT could see every 0.1V as 1 degree of spark advance, so again
for clarity:
> 0.1V = 1 degree of advance
> 1.0V = 10 degrees of advance
> 2.8V = 28 degrees of advance
>
> Since the original spark advance signal is on a range of 0 to 0.4 volts, if I
amped it up x10 then my max output would be 4.0 volts, still well under the 5.0V
max input of the GRT EIS auxiliary ports.
>
> Regards,
> Wade
>
> --------
> Airdog
> Wade Parton
> Building Long-EZ N916WP
> www.longezpush.com
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=476445#476445
>
>
Message 4
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Subject: | Re: Electronic Ignition spark advance signal boost |
Ken,
Awesome. I'll check it out.
Thanks!
Wade
--------
Airdog
Wade Parton
Building Long-EZ N916WP
www.longezpush.com
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=476455#476455
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