HDX Skyview power circuit

[GT3]

I'm in the process of planning my installation and building my load chart, I'm installing a dual HDX 10" setup with 2 SV-battery backups.

The manual schematic "typical electrical installation" calls for both displays to be daisy chained and powered by the same circuit.
My question is, can you and should you isolate each display power sources as PFD and MFD for example?

The PFD to be on the "Main" bus, powered with the Master and MFD on the "Avionics" bus.

Thanks for the help!

 

[lavallejd]

As I recall, your suggested scheme is what is called out in the installation manual for certified systems. PFD on Main, or essential bus and the MFD on the avionics bus.

 

[Rhino]

You can do that if you want. Just use a common ground source, or you may have problems.

 

[lavallejd]

That goes without saying. There are no segregated grounds in this system

 

[Rhino]

Some people use different ground busses or locations. And sometimes in remarkably small airplanes, which actually seems like it would be difficult to do. And yet, they still do it.

 

[GT3]

You can do that if you want. Just use a common ground source, or you may have problems.

This was a given but thanks for the heads up.

 

[Stevec]

I chose to install two circuits with a CB on each. For normal operations turning the master switch on powers everything up but if I just want to put the flaps down I can pull The CBs and I don’t power the screens up unnecessarily.

 

[rjones560]

I'm in the process of planning my installation and building my load chart, I'm installing a dual HDX 10" setup with 2 SV-battery backups.

The manual schematic "typical electrical installation" calls for both displays to be daisy chained and powered by the same circuit.
My question is, can you and should you isolate each display power sources as PFD and MFD for example?

The PFD to be on the "Main" bus, powered with the Master and MFD on the "Avionics" bus.

Thanks for the help!

I would be inclined to put the screens on separate circuits. Putting both on the same circuit risks losing both at the same time.

 

[GT3]

I would be inclined to put the screens on separate circuits. Putting both on the same circuit risks losing both at the same time.

I fully agree but the way I interpreted the certified installation diagram that’s how it was unless I misread. That’s what prompted my questioning…

 

[Rhino]

I don't see that at all. The power connect in Figure 3 on page 13 doesn't show a power connection for the second display at all. Additionally, paragraph 2 of the test procedure on page 101 says, "Apply power to the SkyView display you will be testing. If all of your SkyView displays power up from a single switch or circuit breaker, power down any display..." (emphasis added. The use of the word "If" indicates they may be placed on separate breakers. Paragraph 3 makes a similar statement, almost verbatim.

 

[GT3]

I don't see that at all. The power connect in Figure 3 on page 13 doesn't show a power connection for the second display at all. Additionally, paragraph 2 of the test procedure on page 101 says, "Apply power to the SkyView display you will be testing. If all of your SkyView displays power up from a single switch or circuit breaker, power down any display..." (emphasis added. The use of the word "If" indicates they may be placed on separate breakers. Paragraph 3 makes a similar statement, almost verbatim.

Hi Rhino,

That was my point, figure 3 showed no specific power circuit for the secondary (MFD) display other than the backup battery connection. This lead me to believe that in this "specific" configuration it would feed power from the network wiring as would the ADHARS, AIRINC, EMS, etc, therefore both screens would inevitably be on the same circuit...

This is why I placed my question to the group, I was merely interested in getting feedback from what others had done and see if it was inline with my personal opinion.

In all fairness, I read through the manual quite briskly when I purchased the hardware but now that I'm actually starting my installation I'm paying more attention to these details.

I know you are quite active on the forum, if not THE most active, so I'm sure I'll have more questions as I go and I'm also sure you'll have more opinions!

Thanks for the "help",
Carl

 

[Rhino]

The certified installation manual is lacking in many ways. The second display does not get power from the network. It should have it's own power connection, and both power wires must be used on each display. Each display draws up to 3.5 amps (nominally about 2.4), plus another 1.5 amps if a backup battery is connected. Since the recommended breaker size is 5 amps, you obviously wouldn't want both displays on the same breaker.

 

[GT3]

The certified installation manual is lacking in many ways. The second display does not get power from the network. It should have it's own power connection, and both power wires must be used on each display. Each display draws up to 3.5 amps (nominally about 2.4), plus another 1.5 amps if a backup battery is connected. Since the recommended breaker size is 5 amps, you obviously wouldn't want both displays on the same breaker.

Copy that.

Thank you

 

[tniel7331]

I'm in the process of planning my installation and building my load chart, I'm installing a dual HDX 10" setup with 2 SV-battery backups.

The manual schematic "typical electrical installation" calls for both displays to be daisy chained and powered by the same circuit.
My question is, can you and should you isolate each display power sources as PFD and MFD for example?

The PFD to be on the "Main" bus, powered with the Master and MFD on the "Avionics" bus.

Thanks for the help!

1st get the correct wiring diagram. Attached I don't know what you all are talking about attachment clearly shows 1 primary bus 2 avionics bus

 

[Rhino]

For some odd reason I thought this was for a certified aircraft, which limited his choices for 'official' documentation. My apologies for that.

I also had no idea my level of participation here was a problem for anyone, nor that my content was considered more opinion than "help." I will limit my participation here from now on.

 

[andresmith76]

For some odd reason I thought this was for a certified aircraft, which limited his choices for 'official' documentation. My apologies for that.

I also had no idea my level of participation here was a problem for anyone, nor that my content was considered more opinion than "help." I will limit my participation here from now on.

Dear Rhino - please don't! I, for one, have learned much from your many posts. I appreciate your knowledge and willingness to help others with your insight and experience. This forum would lose a significant resource if you were to start limiting your posts and help.
With regards, Andre'

 

[GT3]

For some odd reason I thought this was for a certified aircraft, which limited his choices for 'official' documentation. My apologies for that.

I also had no idea my level of participation here was a problem for anyone, nor that my content was considered more opinion than "help." I will limit my participation here from now on.

Wow, this thread has taken a very bizarre turn and I’m not sure exactly why…

You are correct, this is for a certified installation and you answered my question on a couple occasions which was appreciated. Now that I understand that Figure 3 on page 13 of the certified manual is incomplete things make more sense, hopefully you can understand my confusion?!? I wouldn’t have thought they would leave something like that out.

I never wanted to imply that your level of participation on the forum was a problem, quite the contrary. I was pointing out that I will surely have to lean on braintrust again in the future.

Unfortunately this type of communication doesn’t lend itself well to convey emotion or intonation which can sometimes cause misinterpretation.

No hard feelings.