---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Mon 12/18/17: 14 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 07:46 AM - Re: Re: Electronic Ignition spark advance signal boost (Robert L. Nuckolls, III) 2. 08:36 AM - Re: Electronic Ignition spark advance signal boost (Airdog77) 3. 08:54 AM - FMEA at ATL? (Andy Elliott) 4. 09:10 AM - Re: Electronic Ignition spark advance signal boost (Airdog77) 5. 09:38 AM - Re: Re: Electronic Ignition spark advance signal boost (Charlie England) 6. 10:05 AM - Re: Electronic Ignition spark advance signal boost (Airdog77) 7. 11:03 AM - Re: Electronic Ignition spark advance signal boost (Eric Page) 8. 11:22 AM - Re: Re: Electronic Ignition spark advance signal boost (C&K) 9. 12:18 PM - DIY captive stud terminal strips (Robert L. Nuckolls, III) 10. 02:15 PM - Re: DIY captive stud terminal strips (rayj) 11. 04:02 PM - Re: DIY captive stud terminal strips (user9253) 12. 04:24 PM - Re: Electronic Ignition spark advance signal boost CORRECTION (Robert L. Nuckolls, III) 13. 04:47 PM - Re: DIY captive stud terminal strips (Robert L. Nuckolls, III) 14. 08:11 PM - Re: Electronic Ignition spark advance signal boost (Airdog77) ________________________________ Message 1 _____________________________________ Time: 07:46:03 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Electronic Ignition spark advance signal boost At 06:27 PM 12/17/2017, you wrote: > >Bob, > >Wow.... thanks! Really takes the guesswork out of configuring the >amp for a gain of 10. > >I'm thinking it most likely doesn't matter, but just to be certain: >the Electroair spark advance signal is only sent out over one wire, >so I would not have any input from the Electroair unit to Pin 1 on >the AD626. I assume this is ok for this configuration? Hmmmmm . . . this offers potential for a different kind of ground loop effect . . . Any difference in voltage between 'ground' on the ignition electronics and the EFIS electronics will manifest as an offset in the system's calibration. Just for grins, let's build this 'adapter' with ground wires that go both directions . . . just hook up the ignition system end and leave the EFIS end open. This configuration will offset the amplified signal with a 1x influence . . . hooking up only the EFIS end would put a 10x gain on the displayed value. I'm thinking the first option offers a high probability for satisfactory performance. Bob . . . ________________________________ Message 2 _____________________________________ Time: 08:36:34 AM PST US Subject: AeroElectric-List: Re: Electronic Ignition spark advance signal boost From: "Airdog77" Bob, Sorry, but I'm having a hard time implementing this in my novice brain: > just hook up the ignition system end at Pin 8 > and leave the EFIS end open. Is this the ground connection that crosses between to the 5V lead (pin 6) via the 0.1 capacitor and the signal ground lead? Any possible way you could diagram this 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=476563#476563 ________________________________ Message 3 _____________________________________ Time: 08:54:59 AM PST US From: "Andy Elliott" Subject: AeroElectric-List: FMEA at ATL? Looks like the infrastructure designers at KATL forgot about FMEA and the concept of single-point failure avoidance. :( Guess they never had an airplane with a dual magneto! -------------------------- Andy Elliott, RV-8, N303RV CL: 480-695-9568 ________________________________ Message 4 _____________________________________ Time: 09:10:51 AM PST US Subject: AeroElectric-List: Re: Electronic Ignition spark advance signal boost From: "Airdog77" Ken, I would think these things (at least a version out there) would go down to 0.0 volts... Roger on using a higher resistor value. Charlie, I think you're saying simply supply 12V power to the op amp (one rated for 12V) at the V+ and V- pins? Spark advance input is obviously unchanged (at +In). I guess the affect on the output being more linear is internal to the op amp? Regards, Wade -------- Airdog Wade Parton Building Long-EZ N916WP www.longezpush.com Read this topic online here: http://forums.matronics.com/viewtopic.php?p=476566#476566 ________________________________ Message 5 _____________________________________ Time: 09:38:28 AM PST US From: Charlie England Subject: Re: AeroElectric-List: Re: Electronic Ignition spark advance signal boost On Mon, Dec 18, 2017 at 11:10 AM, Airdog77 wrote: > > Ken, I would think these things (at least a version out there) would go > down to 0.0 volts... Roger on using a higher resistor value. > > Charlie, I think you're saying simply supply 12V power to the op amp (one > rated for 12V) at the V+ and V- pins? Spark advance input is obviously > unchanged (at +In). I guess the affect on the output being more linear is > internal to the op amp? > > Regards, > Wade > > -------- > Airdog > Wade Parton > Building Long-EZ N916WP > www.longezpush.com > > My comment was based on using one of the ancient op amp circuits, most of > which get a bit nonlinear when output approaches the supply rail voltage. > The much more modern instrumentation amp that Bob referenced doesn't seem > to have that issue, making it simple to power it from the EFIS's 5V source. On Bob's comment about ground references: I'm not up to speed on that device, but I'd expect a differential amplifier to look at the voltage difference between the two source voltages, and in this case, the <-> input would be the ground reference at the device you're measuring. Since it's a differential amplifier, I'd expect it to be immune to ground reference issues, but hey; you don't know until you test. If I were setting it up, I'd start by hooking the <+> input to the advance output, the <-> input to the ground terminal *on the ignition module*. I'd supply power from the EFIS & ground from the same spot the EFIS gets its ground. I wasn't sure what Bob meant in his previous post, either, but he may have been saying to supply ground from the ignition module; the same point that supplies 'reference' to the <-> input. (By 'ground', I'm talking about the power supply ground terminal; not the <-> input to the amp.) ________________________________ Message 6 _____________________________________ Time: 10:05:55 AM PST US Subject: AeroElectric-List: Re: Electronic Ignition spark advance signal boost From: "Airdog77" Charlie, Yes. Tracking. When I checked the Electroair manual, interestingly enough the only ground available on that unit is the ignition module ground (vs the controller unit).... since I was scrounging around to find a ground to use for -In on the AD626 that Bob recommended. Cheers, Wade -------- Airdog Wade Parton Building Long-EZ N916WP www.longezpush.com Read this topic online here: http://forums.matronics.com/viewtopic.php?p=476571#476571 ________________________________ Message 7 _____________________________________ Time: 11:03:59 AM PST US Subject: AeroElectric-List: Re: Electronic Ignition spark advance signal boost From: "Eric Page" Yes, I believe Bob meant to ground both signal and supply at the ignition module. The op-amp won't know if there's a few mV ground potential difference on the supply side; just the signal side. So, grounding the supply at the ignition module instead of at the EIS won't affect operation, but it *will* give the op-amp a good reference for the advance signal. Wade, which model of the GRT EIS are you using? If it's the 4000, there appears to be a "4.8V Exitation Output" on pin 25. The AD626 will draw a small fraction of a milliamp, so it should be safe to use this pin to power the circuit. Eric Read this topic online here: http://forums.matronics.com/viewtopic.php?p=476573#476573 ________________________________ Message 8 _____________________________________ Time: 11:22:11 AM PST US Subject: Re: AeroElectric-List: Re: Electronic Ignition spark advance signal boost From: C&K Wade As you surmise, there has to be two wires to to get the signal to your amplifier and on to the EIS. So pin 1 of the amplifier in Bob's diagram has to be grounded. The complication is that you can ground that pin to numerous places in the aircraft and each of those places will typically give a slightly different reading when dealing with millivolt sensor signals. This may or may not be significant in your application. Grounding pin 1 to the ignition unit which is the source of your signal will likely be the best choice and we recommend that you try that. If that is difficult in your particular aircraft, or it proves unsatisfactory, the next choice would probably be to try grounding pin 1 at the EIS ground. The issue with that is that any voltage difference between the ground at the ignition unit and the ground at the EIS will be amplified by a factor of 10 by the AD626. That may or may not be significant depending on exactly what currents are flowing and what the resistance is between the two different physical ground points. That difference can change when you turn on or off various electrical circuits in the aircraft which might introduce measurement errors. If this makes sense to you, congratulations, you now understand the concept of a ground loop and you can appreciate why bringing most of our aircraft grounds to the common "forest of tabs" makes sense. Even grounding both the EIS and the ignition unit at a forest of tabs might not totally eliminate these ground errors though as there may well be millivolt differences in the wire between the forest of tabs and the ignition unit. All wires and connections have some resistance and any current through a resistance results in some voltage drop however small. We are trying to avoid adding such a voltage drop to your millivolt sensor signal. So again running a ground wire from pin 1 of your amplifier all the way to a connection at the ignition unit can make sense. I am not familiar with your ignition but if your ignition coils are grounded through a remote ignitor on the engine side of the firewall, it is more likely that it will not matter where you ground the amplifier pin. Coil grounds pulse several amps and you don't want that running through the same wire as your sensor ground. Ken On 18/12/2017 12:36 PM, Charlie England wrote: > > > On Mon, Dec 18, 2017 at 11:10 AM, Airdog77 > wrote: > > > > > Ken, I would think these things (at least a version out there) > would go down to 0.0 volts... Roger on using a higher resistor value. > > Charlie, I think you're saying simply supply 12V power to the op > amp (one rated for 12V) at the V+ and V- pins? Spark advance input > is obviously unchanged (at +In). I guess the affect on the output > being more linear is internal to the op amp? > > Regards, > Wade > > -------- > Airdog > Wade Parton > Building Long-EZ N916WP > www.longezpush.com > > My comment was based on using one of the ancient op amp circuits, > most of which get a bit nonlinear when output approaches the > supply rail voltage. The much more modern instrumentation amp that > Bob referenced doesn't seem to have that issue, making it simple > to power it from the EFIS's 5V source. > > > On Bob's comment about ground references: I'm not up to speed on that > device, but I'd expect a differential amplifier to look at the voltage > difference between the two source voltages, and in this case, the <-> > input would be the ground reference at the device you're measuring. > Since it's a differential amplifier, I'd expect it to be immune to > ground reference issues, but hey; you don't know until you test. > > If I were setting it up, I'd start by hooking the <+> input to the > advance output, the <-> input to the ground terminal *on the ignition > module*. I'd supply power from the EFIS & ground from the same spot > the EFIS gets its ground. I wasn't sure what Bob meant in his previous > post, either, but he may have been saying to supply ground from the > ignition module; the same point that supplies 'reference' to the <-> > input. (By 'ground', I'm talking about the power supply ground > terminal; not the <-> input to the amp.) > > ________________________________ Message 9 _____________________________________ Time: 12:18:54 PM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: DIY captive stud terminal strips A short time ago we had some discussions that included the mention of a technique for crafting captive stud terminal strips. Just ran across some pictures of an exemplar technique . . . https://goo.gl/cMQtA4 The base is crafted from some durable insulating material. The article illustrated is built on a piece of Delrin. Alternative materials include 6/6 nylon, phenolic, PVC and some thermoplastics. Counter-sink the studs about 0.03 under-flush and back-fill with epoxy . . . JB Weld is good. Bob . . . ________________________________ Message 10 ____________________________________ Time: 02:15:26 PM PST US Subject: Re: AeroElectric-List: DIY captive stud terminal strips From: rayj Many JB Weld products are steel reinforced. Is it possible that the JB Weld used to secure the bolts might be conduction path if the terminal strip is mounted on a conductive surface? Raymond Julian Kettle River, MN The things we admire in men, kindness and generosity, openness, honesty, understanding and feeling are the concomitants of failure in our system. And those traits we detest, sharpness, greed, acquisitiveness, meanness, egotism and self-interest are the traits of success. And while men admire the quality of the first they love the produce of the second. -John Steinbeck, novelist, Nobel laureate (1902-1968) On 12/18/2017 02:18 PM, Robert L. Nuckolls, III wrote: > > > A short time ago we had some discussions that > included the mention of a technique for crafting > captive stud terminal strips. > > Just ran across some pictures of an exemplar > technique . . . > > https://goo.gl/cMQtA4 > > The base is crafted from some durable insulating > material. The article illustrated is built on a > piece of Delrin. Alternative materials include > 6/6 nylon, phenolic, PVC and some thermoplastics. > > Counter-sink the studs about 0.03 under-flush > and back-fill with epoxy . . . JB Weld is good. > > > Bob . . . > > > > ________________________________ Message 11 ____________________________________ Time: 04:02:12 PM PST US Subject: AeroElectric-List: Re: DIY captive stud terminal strips From: "user9253" According to JB Weld website https://www.jbweld.com/pages/faqs Will J-B Weld conduct electricity? No. J-B Weld is not considered to be a conductor. It is an insulator. -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=476591#476591 ________________________________ Message 12 ____________________________________ Time: 04:24:42 PM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Re: Electronic Ignition spark advance signal boost CORRECTION > >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 There are hundreds of combinations of jelly-bean parts that would suffice to your design goals. My personal favorite of the moment is the Analog Devices AD626 instrumentation grade amplifier. It works well at 5.0 volt supply, has a huge common mode input range, features factory trimmed preset gains of 10 or 100. Has an output range that easily brackets your requirement (0.03 to 4.7v). The beauty of this critter is that no external resistors or calibration adjustments are needed to address your task. https://goo.gl/Q3SYvj They're a little pricey compared to some other candidates https://goo.gl/fxuF4Z but I think the convenience of minimizing external components combined with the simplicity of calibration more than offsets the difference in cost. I used this chip in dozens of data acquisition tasks at Beech . . . it's still a work-horse in my toolbox of get-er-done parts. CORRECTION . . . Must have suffered a transient short between the headphones. Blew of the AD626 feature that makes it 'magic'. The inputs have a huge common mode signal rejection range. This means that it amplifies only what is impressed between pins 1 and 8 while ignoring the difference in voltage between 1,8 and 2,3. Hence, you tie pin 1 as close as practical to ignition system ground, pin 8 to the advance signal output. Amplifier ground pins 2,3 tie to EFIS signal ground. This insures that the output between 5/2,3 is 10x that between 8/1 irrespective of any difference in 'ground' of the ignition system vs. the EFIS system. Emacs! Bob . . . ________________________________ Message 13 ____________________________________ Time: 04:47:46 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: DIY captive stud terminal strips At 04:14 PM 12/18/2017, you wrote: > >Many JB Weld products are steel reinforced. > >Is it possible that the JB Weld used to secure the bolts might be >conduction path if the terminal strip is mounted on a conductive surface? > >Raymond Julian >Kettle River, MN Not sure how much the epoxy's strength can be attributed to particulate steel . . . but the data sheet . . . https://goo.gl/mHXUZX suggests that any electrical contact between such particles is nil to zero volume resistivity of JB weld is 3.16 x 10^15 while that of copper is about 1.7 x 10^-8 if I recall correctly. This means that JB Weld is pretty good electrical insulator! Bob . . . ________________________________ Message 14 ____________________________________ Time: 08:11:07 PM PST US Subject: AeroElectric-List: Re: Electronic Ignition spark advance signal boost From: "Airdog77" Hi Ken, I talked with Electroair earlier today. They are taking a look at the AD6262 and the best place to tie in the ground. It doesn't show up in the manual and honestly I forgot about it, but on the experimental version there is a ground wire coming off the Electroair controller unit. Their initial thought is that would be the best place to tie in the A626 ground input. I'll await Electoair's evaluation and press on from there. Thanks a ton for all your advice. Regards, Wade -------- Airdog Wade Parton Building Long-EZ N916WP www.longezpush.com Read this topic online here: http://forums.matronics.com/viewtopic.php?p=476595#476595 ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message aeroelectric-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/AeroElectric-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/aeroelectric-list Browse Digests http://www.matronics.com/digest/aeroelectric-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.