495 to SL30 connections

Greg Arehart · #1 10-03-2008, 05:22 PM

Just got myself a Garmin 495 which I want to connect to my SL30. GPS495 manual says to "connect the data out pin on the 495 (blue wire) to the RxD pin on the SL-30." According to my SL-30 installation manual, there IS NO RxD pin on the Comm side of the radio. There IS an RxD pin (#4) on the Nav side, but that is already wired into my Dynon D-100. What do I do? How do these interface?

Thanks,

greg

mburch · #2 10-03-2008, 05:46 PM

Quote:

Originally Posted by Greg Arehart

Just got myself a Garmin 495 which I want to connect to my SL30. GPS495 manual says to "connect the data out pin on the 495 (blue wire) to the RxD pin on the SL-30." According to my SL-30 installation manual, there IS NO RxD pin on the Comm side of the radio. There IS an RxD pin (#4) on the Nav side, but that is already wired into my Dynon D-100. What do I do? How do these interface?

Greg,

I think you have the correct pin. A serial input can only receive data from one source, so you'll have to decide whether you want the radio to be connected to your GPS or your EFIS.

good luck,
mcb

Greg Arehart · #3 10-03-2008, 06:23 PM

Matt,

Thanks for the quick reply. That's what I suspected, but certainly not what Garmin provides in the instructions. So, perhaps the best situation might be to put a toggle with two inputs (one from the Dynon, the other from the 495) so I could swap between the two? Do you see any problems with that?

thanks,
greg

mburch · #4 10-03-2008, 07:21 PM

Quote:

Originally Posted by Greg Arehart

So, perhaps the best situation might be to put a toggle with two inputs (one from the Dynon, the other from the 495) so I could swap between the two? Do you see any problems with that?

It seems like that would work, although if it was my airplane and I was faced with adding a separate toggle switch to enable this feature, I'd probably be content with reaching out my hand to tune the knobs on the radio instead.

good luck,
mcb

Rivethead · #5 10-03-2008, 07:30 PM

What is it that you're trying to do? My system sounds similar to yours and is wired and working.

Greg Arehart · #6 10-03-2008, 09:00 PM

Not really sure what I'm trying to do other than have these things talk to each other. As I am now flying a 1961 C172, all this electronic stuff is new to me. My understanding (poor as it is) is that the radio frequencies can automatically be sent from the GPS database to the SL30. As you indicate Matt, I'm not sure that is worth the switch. My other understanding is that some of the GPS info can be sent to the Dynon (D100) to drive things like the HSI. This is much of the part I don't understand - Rivethead, is there a simple way to wire the 496 to send this kind of data to the Dynon? In the end, I'm not sure I NEED any of this, but as long as I have the equipment, why not try to get the most out of it.

Thanks for any advice.

greg

SteinAir · #7 10-03-2008, 10:14 PM

Hi Greg,

As far as I know the Dynon will not pass through the GPS freq data to the SL-30 like some other EFISes will....so, as Matt said the radio can't have 2 Rx's, so you're stuck with a switch or only using one item. Note, the frequencies to SL-30 are a marginally nifty feature, but hardly something I'd go out of my way to enable.

It's not really Garmin's fault, because the SL-30 is mainly meant to be wired up to run CDI's, etc.. or to attach to EFISes. The radio came first (not by them), the GPS came later. In normal installations without an EFIS running through the serial lines, a CDI or such runs through analog connections, leaving the serial line open for the GPS. It's our wonderful world of experimental EFISes having the ability to communicate with the radio via serial lines that is complicating your install.

Anyway, in the end you're stuck with a toggle or perhaps just not using the freq load. I don't find it to be a "must have" bit of functionality over a CDI myself....but that's just me. However, some EFISes (and perhaps someday Dynon-I just don't know) will pass the GPS freq data through the EFIS to the radio, eliminating that issues.

My 2 cents as usual!

Cheers,
Stein

Greg Arehart · #8 10-03-2008, 10:29 PM

So, it sounds like the simplest solution is just to wire up the GPS as a standalone unit and not try to get it to pass information anywhere. I already have the harness connecting the Dynon to the SL30. It's really not a big deal to twist the radio knobs to set a frequency. I had just been wondering about all this since the install manuals for the Garmin stuff are clearly not for the uninitiated amateur like me (but I sure like the Dynon manuals, which provide clear and simple info!).

Thanks

greg

rvmills · #9 10-04-2008, 12:43 AM

Greg,

Is what you are trying to accomplish the following?:

1. Send the 495 GPS track data from the 495 to the Dynon, plus
2. Send the 495 freq (autoload) data from the 495 to the SL-40, plus
3. Send the SL-30 Nav (VOR/ILS) signal to the Dynon.

I have a D100/396/SL-40 set-up, and for 1. and 2., I split the blue wire out from the 396 and connected to pin 22 on the Dynon and the RxD pin (I believe, will check) on the SL-40. I do get track data on the D100 and Freq loading on the SL-40.

Seems the set up would be the same with the SL-30 for 1. and 2., and I'd think the SL-30 would have a separate pin to transmit VOR/ILS Nav data out (but that's where I could be wrong!). But if it did, that way you'd get all the features you want. Have you checked for a transmit pin, or is pin 4 either transmit or recieve (and you must choose one)? I looked on Garmin's website and couldn't find an install manual to research it...no joy there. I do know that you'd have to wire the SL-30 Nav signal and 495 Nav signal through a 3-way switch to the Dynon, or use an HS-34, to get both GPS and VOR/ILS to the Dynon (see page 3-5 on the D100 install manual).

I could be way off on this, so take it with a grain of salt. Maybe you have to choose between "data in" or "data out" to/from the SL-30. Stein and the other smart avionics guys would know best on that.

Good luck! Also, sent you a PM...got ya a spot in the hangar on Nov 1st! Gimme a call!

Cheers,
Bob

Cheers,
Bob

uk_figs · #10 10-04-2008, 10:03 AM

I have a similar setup but with the HS34, everything appears to be working but I am not flying yet to be sure.
I have the 496 TX line wired to a terminal block that fans out as follows:
1. HS34 Pin 1 (serial 1 RX) GPS input to HSI
2. SL30 Pin 4 (serial RX) Frequency upload to standby channel
3. ADI II Pin 17 (serial RX) GPS track to autopilot
4. SL30 Pin 5 (serial TX) goes to HS34 Pin 2 (serial 2 RX) SL30 NAV to HSI
This is to enable 496 frequency upload to SL30 standby channel, GPS input to D100 HSI, GPS track into the A/P and SL30 into the D100 HSI. . The HS34 switches the NAV inputs between the GPS and the SL30.
From all the manuals and everything else I have read this should work, have I missed something in this setup? From looking at the SL30 manual and the D100 manual I could not see what I would get from the D100 TX to SL30 RX connection and the 496 RX connection seems to only be of value if you have a GTX 330 transponder for TIS information (I have a GTX327)