[vinzer]

For some time I had a dilemma about which ignition system to install in place of my PMAG.

Until now, my first RV-10 has been equipped with a PMAG on one side and a classic Slick magneto on the other. Over time, I went through several ignition configurations: dual Slicks, then dual Lasars, then one Lasar with one Slick, and finally the current setup with a left-side PMAG and right-side Slick.

What I personally never liked about the PMAG is that it is a completely closed system. You really do not know what is happening inside or exactly what ignition timing the engine is running at. As an avionics developer and manufacturer, I naturally like to have some level of visibility and control over what is happening, especially when it comes to something as important as ignition timing. I understand that this may be critical only for me, while others may say Ehh who cares.

While working on a couple of side avionics installation projects, I had the chance to install SDS EFI CPI-6 systems for clients. I liked the design and the overall approach SDS EFI took with their ignition system.

This thread is not intended as an advertisement for SDS products. I simply want to share my own experience, the issues I ran into, and the solution I came up with.

I finally pulled the trigger and bought a CPI-2 system from them. For now, I decided to use only a single-side coil setup, even though I purchased the dual version. The main reason is that my panel is already very crowded. I test a lot of avionics in my aircraft, because every product I design has to fly in that panel, so every square inch of panel space is very valuable almost like expensive real estate. Just joking, of course, but only partly.

The SDS CPI-2 control head is actually a small unit and only requires about a 3-inch opening, but in my case even that space was not available. Eventually I will redesign the panel when my second RV-10 is built and flying, but for now I needed another solution.

And I found one.

I realized that I already fly with three large 10-inch touchscreen EFIS displays, so there was no reason I could not integrate the SDS control interface directly into my EFIS.

SDS EFI is a closed system and, understandably, they do not provide public information for integration with other avionics. That makes sense, because they do not want critical engine-control components to become dependent on other equipment. But we are flying experimental aircraft, so I decided to carefully give it a try. My project is completely unofficial!

The result is that I was able to integrate the SDS control head interface into my avionics system and emulate the display/control functionality directly on the EFIS. So now I can fully control ECU of the ignition system from the touch display as it would be from their control head

And guess what it works great.

Now it is time to fly it and test it properly.

 

[RWoodard]

Very cool.

Aesthetics wouldn’t keep me from installing their system, but I always cringe at the thought of putting their controller into any modern Garmin-based panel. Same reason I don’t like the Mountain High built-in O2 controller.

I’m not much of a tinkerer when it comes to squeezing max performance out of my ignition system (or anything else for that matter). I’m more of a set it and forget it person. Once I found an ignition curve that works and is safe for my application, I’d probably just leave it alone unless I needed to access the data for troubleshooting. Hence, an otherwise hidden screen would be ideal. Saves panel space and reduces visual noise in my panel.

To the awesome folks at SDS, please embrace what Vinzer has done and figure out how to offer this as an option to us Dynon and Garmin fanboys!

Just my $0.02

 

[dmattmul]

For those building an airframe with either SDS or EFII it's fairly straight forward (Especially with a GAD 29) you can integrate AFR and amps your fuel pumps are pulling into ones EFIS. I did this on mine and works great, especially for data analysis and tuning.

 

[lr172]

a bit of caution is possibly warranted here. The TDC offset data element is critical for sparking in the correct time. have no idea the potential for errors in this lnk, but a change to that config item would make a mess. maybe the cpi has a config lock variable like the sds 6 does and may make sense to use it here.

great ingenuity here!

 

[vinzer]

a bit of caution is possibly warranted here. The TDC offset data element is critical for sparking in the correct time. have no idea the potential for errors in this lnk, but a change to that config item would make a mess. maybe the cpi has a config lock variable like the sds 6 does and may make sense to use it here.

great ingenuity here!

Larry, you are absolutely correct. That parameter which is 'magnet position' is actually critical for the proper operation of the whole system. My “SDS gateway” cannot change that parameter on its own. It can only do so when physically commanded by a button press from the EFIS, exactly the same way it would be commanded from the original SDS control head.
From what I can see, both the SDS6 and CPI-2 systems appear to follow the same general philosophy, with configuration lock protection for critical parameters. I would assume that access to this menu, and any change to the magnet position setting, is normally only required during the initial setup.
Once the engine, pickup sensor, and magnet position are correctly configured, this should normally be a “set once and leave alone” parameter, unless the engine or pickup sensor installation is changed in the future.

 

[lr172]

Larry, you are absolutely correct. That parameter which is 'magnet position' is actually critical for the proper operation of the whole system. My “SDS gateway” cannot change that parameter on its own. It can only do so when physically commanded by a button press from the EFIS, exactly the same way it would be commanded from the original SDS control head.
From what I can see, both the SDS6 and CPI-2 systems appear to follow the same general philosophy, with configuration lock protection for critical parameters. I would assume that access to this menu, and any change to the magnet position setting, is normally only required during the initial setup.
Once the engine, pickup sensor, and magnet position are correctly configured, this should normally be a “set once and leave alone” parameter, unless the engine or pickup sensor installation is changed in the future.

a solid approach. yes, once initially set and confirmed, it should never need to be touched again.

 

[akschu]

I like this a lot. A few questions:

1. If you aren't on the CPI2 page and there is a fault, will that fault be raised to a warning on the screen?
2. Does the EFIS support external warning lights?
3. Does the EFIS have dual diode or'd inputs?
4. Any possibility of this working on the ELM310 or better, the ELM310 in the Engood form factor? It would be great to replace the CPI2 head with another source of attitude that has no dependancies on the existing panel.
5. What's the protocol look like? I've never probed around mine with a logic analyzer, but I've always suspected it's just a dumb text protocol.

 

[vinzer]

I like this a lot. A few questions:

1. If you aren't on the CPI2 page and there is a fault, will that fault be raised to a warning on the screen?
2. Does the EFIS support external warning lights?
3. Does the EFIS have dual diode or'd inputs?
4. Any possibility of this working on the ELM310 or better, the ELM310 in the Engood form factor? It would be great to replace the CPI2 head with another source of attitude that has no dependancies on the existing panel.
5. What's the protocol look like? I've never probed around mine with a logic analyzer, but I've always suspected it's just a dumb text protocol.

Sure, I am happy to answer your questions.

1. If the fault light turns on, the EFIS will treat it as an external fault condition. It will display a global warning message and, if voice warnings are enabled, it will also generate a voice alert from EFIS.
2. The EM-02 EMS module has two outputs for connecting external panel warning lamps. These are primarily intended for low oil pressure and master warning indications. So any master warning in EFIS will trigger a lamp in EM02.
3. No, the current ELM800 and ELM1000 models use a single power supply input only. However, both models have built-in protection on the power input lines.
4. I am planning to expand this support CPI2 to the ELM310 and ELM312 models as well. Please note that CPI-2 support is currently unofficial, so it should be treated as very experimental at this stage.
5. The SDS communication uses low-level binary data with CRC. It is not a protocol that can be directly used by a typical EFIS. For this reason, I had to design an additional small MCU-based protocol conversion module, which receives the SDS data and converts it in both directions for use with the EFIS (in my case CAN bus).

I hope this answers your questions.