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Dynon AHRS and HUB question

Mdragon

Active Member
Can't get to the hangar to test this out right now, and trying to plan routing.

Does anyone know if the AHRS can be plugged into a dynon hub, and then the hub run to the HDX display? The way the Dynon wiring diagram shows it the AHRS is routed directly to the display serial port. It I can run to a hub it will simplify my wiring.
 
I hope so - I'm planning on that, too. I'm using AzGila's excellent hub kit, which includes the servo connectors.

Skyview Layout (Az_Gila's Hub).jpg

Dave
 
You can run SkyView network connections in series, parallel or any combination of the two.

I suggest however that you overlay some “what if” ideas into your design. For example I tend to run separate network lines for each SkyVIew display such that I don’t have everything on a single, series connected network run. Perhaps overkill but it is easy enough to do.

Carl
 
Can't get to the hangar to test this out right now, and trying to plan routing.

Does anyone know if the AHRS can be plugged into a dynon hub, and then the hub run to the HDX display? The way the Dynon wiring diagram shows it the AHRS is routed directly to the display serial port. It I can run to a hub it will simplify my wiring.

I assume when you say "serial port" you're referring to the Skyview Network port - the serial data connections to the displays are a different animal and aren't used by the ADAHRS.

I feel this is important to mention since conflating the Skyview Network connector with an RS232 connector could result in some very bad juju, to the point that it's called out specifically in the install manual:

It is important to understand that in SkyView, the 9-pin connectors are not electrically compatible with RS-232 serial connections found on PCs and other devices. One critical difference is that in a SkyView Network 9-pin D9F or D9M connector, 3 of the 9 pins provide power, which, if connected to a RS-232 serial device, could damage it, or damage the SkyView display.

As others have mentioned, no problem with using a hub. I ended up installing two hubs, one forward and one aft. Arguably slightly overkill, but it allows me to only have a single SVN run from front to rear.
 
So to make this perfectly clear, I can plug in for instance the AHRS, 2 autopilot servos into a dynon 5 port hub, and then run this forward with a db9 directly to the display serial in?

Another question. Dynon manual says you can at any point combine the twisted wires of the servos together. Does this mean you can connect the roll servo and pitch servo wires together, and that the HDX somehow encodes commands to the proper servo when it wants to actuate it, using the same wires?

Wasn't quite clear to me in how it was described in install manual.


Thanks for help so far.
 
Another question. Dynon manual says you can at any point combine the twisted wires of the servos together. Does this mean you can connect the roll servo and pitch servo wires together, and that the HDX somehow encodes commands to the proper servo when it wants to actuate it, using the same wires?

Wasn't quite clear to me in how it was described in install manual.


Thanks for help so far.

Network connections are all common to each other. The SkyView knows what is on the network, and how to talk to each unit separately. In other words think digital, not analog.

For each autopilot servo I use a single four #22 conductor shielded wire, a #20 wire for power, a #20 wire for ground and a #22 wire for disconnect. I use a female and male 9 pin D connectors at the servo to make the connection. Easy peasy.

Carl
 
Servo wiring

The servos can be connected to a hub with the ADAHRS but the power doesn't unless, as Dave mentions, a special hub is utilized.
Note, if the Advanced Flight Systems Advanced Control Module is used, the components all terminate at the ACM.
 
Network connections are all common to each other. The SkyView knows what is on the network, and how to talk to each unit separately. In other words think digital, not analog.

For each autopilot servo I use a single four #22 conductor shielded wire, a #20 wire for power, a #20 wire for ground and a #22 wire for disconnect. I use a female and male 9 pin D connectors at the servo to make the connection. Easy peasy.

Carl

OK that makes more sense. Was thinking analog and not digital. Hoping to wrap this up this week.
 
Skyview Network DB9

Marc, The Skyview network DB9 connector carries required info from both A/P servos and ADAHRS unit plus other devices in the network.
So, both roll and pitch servos go into identical pins that Skyview sorts out internally. 7 wires in each servo. 4 go into the Network Hub via the DB9.
The blue goes into pin 6. The green goes into pin 1. The white/blue goes into pin 4. The white/green goes into pin 8. That leaves 3 servo wires. Red(power), Black(local ground at the servo site if you choose), Yellow(Autopilot disconnect). So, yes, with DB9s, you are essentially splicing same color wires together from all the devices. Clear as mud?
Wendell
 
Marc, The Skyview network DB9 connector carries required info from both A/P servos and ADAHRS unit plus other devices in the network.
So, both roll and pitch servos go into identical pins that Skyview sorts out internally. 7 wires in each servo. 4 go into the Network Hub via the DB9.
The blue goes into pin 6. The green goes into pin 1. The white/blue goes into pin 4. The white/green goes into pin 8. That leaves 3 servo wires. Red(power), Black(local ground at the servo site if you choose), Yellow(Autopilot disconnect). So, yes, with DB9s, you are essentially splicing same color wires together from all the devices. Clear as mud?
Wendell

Thanks Wendell!

I have all the wires run, servos mounted, and the panel cut, now it is the 20 percent of the work left that takes 80 percent of the time! The grommets helped a bunch, thanks again. Ended up with the wrong sizes on the ones I ordered from Vans. I've spent way too much time crammed in that plane, making me wish I was 4 foot 8 and not 6 foot 5.
 
Servo power

When connecting the servos the power wires do not connect to the skyhub, only the communication wires.


The servos use too much power to be connect via the hub.


David
 
Hub

I did this on my -7. The ADAHRS (dual) run to a hub aft of the baggage compartment panel and so does both servos. Then one network cable runs to a second hub behind the panel. Seen here

http://mykitlog.com/users/display_log.php?user=sdahrens&project=248&category=9948&log=204895&row=52

I did this to reduce the number of wires running through the center section. Been working fine for a few years. Each device has a unique address similar to a MAC address on computer networks so the system can differentiate between devices.
 
Just Making sure...

So to make this perfectly clear, I can plug in for instance the AHRS, 2 autopilot servos into a dynon 5 port hub, and then run this forward with a db9 directly to the display serial in?

Mdragon: The ADAHRS boxes use the SV Network (aka SkyView Network) which is different that a "Serial In" or "Serial Port"
The SV Bus uses Data 1A, Data 1B, Data 2A & Data 2B along with power & ground wires, Typical connector is a DB9.
A Typical "Serial port" uses things like Serial 1 Tx & Serial 1 Rx, these signals can use as few as 2 pins of more (Tx+, Tx-, Rx+, Rx- as examples).
I am very familiar with the Adv Flt 5600 series but not the HDX, I did a quick look at the Dynon manual after downloading so feel my info is exact.
So - It's either an "SV Network" or a "Serial Port", you might have already understood that but your exact words worried me a little.
 
I hope so - I'm planning on that, too. I'm using AzGila's excellent hub kit, which includes the servo connectors.

View attachment 12083

Dave
In looking at this from a system safety standpoint, what I don’t like is that there are single point failures that will take out all of the important functions of the display. The single line from the hub to the display is the potential culprit. If you simply plug the ADAHRS into the other Skyview network plug on the display you greatly improve the situation.
While Dynon runs dual independent busses on the Skyview network, all coonnections are in a common connector, reducing redundancy.
 
Dave,
What is the AzGila hub kit and is it similar, or better in some way to the Dynon 5 port network hub?
Thx
Paul.

az_gila, that is, Gil Alexander, had a hub kit that he offered. Don't know if he still does. I couldn't find it using the VAF search feature.

As I recollect, it was a bare board to which you supplied your own hardware and soldered them on. He provided a shopping list and the parts were easy enough to get, and a friend soldered the parts on. His hub has 5 male connectors for the normal network, plus 2 female ones for the servos. There's also a Molex connector for the servo power, ground and autopilot disconnect. It's a really well-thought-out unit and I'm very glad that I got one.

AzGil's Hub Board.jpg

It is not sealed and does not have a cover. Steve Melton 3D printed me a simple stand-off for the bottom that blocks any debris from getting to the soldered side. The stand-off was a custom order.

The standard Dynon hub only has the 5 male connectors, if I remember right.

Dave
 
Finally, here's the completed hub on the stand-off:

AzGila Hub Stand-Off 2 S.jpg

Sorry, I don't know how to embed multiple VAF-hosted photos in a single posting.

Dave
 
AzGila hub

Thanks Dave for the info on the Gil Alexander hub, that looks like a very nice and tidy way to extend the Skyview Network. I think it's great!
 
New Dsub pins in Dynon and Electronics International Harnesses

I installed my Dynon 3 screen EFIS in my RV10 in late 2019. I probably had all the components delivered by the first half of 2019. Back then they were using the gold plated male and female pins that had a hole for the wire to go in and they were crimped on with a 4 pin crimper. I have a nice one that came from Boeing Surplus, even if I don't know the correct name for that kind of crimper. Since then I helped a friend upgrade the panel in his 20 year old RV8A. He put in a HDX1100 with everything else that you could buy to go with it. One of the things that I noticed is that all the Dsub cables have different pins in them. Instead of a round hole for the wire they have a molex style crimp on the wire. The problem with these is that the crimps are not round and it is nearly impossible to get a pin extractor past the crip to extract the pin. This is less of an issue with a short network cable that can be easily removed and replaced entirely. However from a maintenance point of view it would be really nice if it was possible to extract a pin on a damaged wire and replace the wire and pin. With this these new cables the only choice would be to cut the connector off and put a whole new connector on. Not much fun for a D37 connector.

A friend of mine has an Electronics International engine monitor that he just put in. They crossed up one pair of wires on a D37 that has all the wiring for his CHT, EGT sensors. I thought that it would be an easy fix to extract two pins and put them in the right place. However the crips were not round at all and had appendages sticking out the diameter of the hole, making it impossible to get the extraction tool by the crimp. So far Electronics International has just said "well sorry" but offered no solution. Putting in a new wiring harness would be a big job. I would be easier to cut the old D37 off and install a completely new one (with the high quality pins of course).

At least Dynon was willing to talk to me about this issue. It seems that they have a machine to make the crimps that is quite fast so things are not likely to change. If I was putting Dynon in now I would make all my own cables to make sure maintenance and repair in the future was easier. Electronics International would not even talk to me about this issue. They just hung up the phone on me. You can look at that any way you like.
 
A Few What IF's

I have a 3 screen Dynon EFIS in my RV10. I have 2 ADAHARS in the tail cone. Yes I could run one network cable for both ADAHARS, pitch servo and Yaw servo. However I do not have another independent ADI. With 3 screens that can be a PFD, and their own battery backup I thought it was not necessary. However that one network cable caused me some concern as a single point of failure. What I did was install a 5 port hub on each side of the cockpit and ran separate network cables from each side of the cockpit to each ADAHARS. No single cable failure can wipe out ADAHARS to the entire cockpit.
I helped a friend upgrade the panel in his 20 year old RV8A. He only has one EFIS, but he has a Garmin G5 display with a GAD29 to send it NAV information from his Avadine 440. We plugged the network cable from the back (2 ADAHARS and pitch servo plugged into a hub) directly into the EFIS rather than the front hub. Our point of view was that the less connectors the ADAHARS went through the better as they are just about the most important component in the system. However he has the G5 as backup ADI so he should be fine. This is an IFR aircraft flown by a very accomplished professional pilot. He flies it IFR when he needs to and needs it to be reliable.

The point is to think about what could fail, and how that might impact your flight. If it is a VFR aircraft, if all flight instruments failed, you could navigate to an airport with your IPad and land without any flight instruments quite easily. If it's an instrument aircraft, you want to be able to continue to fly in the soup until you can get out of it. That requires backups. Each situation is different.
 
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