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Magnetometer - powering it via multiple sources?????

Posted: Tue Mar 24, 2020 4:32 pm
by maniago
I have dual HXrs and a mini-x as backup. I can switch the ADAHARs to get info from any one of these and it works fine. BUT I have the magnetometer powered by the mini only as it has an internal battery backup and in theory should never go down. But who knows, it might and then my magnetometer data is gone. Id like to install a on-on-on 3way switch to have the capability to power from any of my EFISs.

QU: Can I just switch the power sources, or do I need to switch the gnd sources as well?

If just switching the power ok, should I

1)grab gnd from a central location instead of off the mini......or

2) tie all the EFIS magnetometer gnds together?

Thanks for any info

Re: Magnetometer - powering it via multiple sources?????

Posted: Fri Mar 27, 2020 12:19 am
by GRT_Jeff
If you have a Dual AHRS then there is only one mag power connection there. One Dual AHRS and one Mini would be two power outputs.

I think I will have to get some advice from the engineer on this. Switching the grounds sounds like the safest option. Using a central ground could add noise to the system or drop the voltage level. Definitely don't connect the ground pins together.

If you don't switch the grounds then what's best changes depending on the main power source. When running off the internal battery it would be best to use the Mini's ground. When not running off the internal battery, a central ground is better than the Mini ground.

The magnetometer power outputs are diode-protected so in theory you could connect them together without a switch, but I'm not sure that's a good idea and you still have the ground issue.

Re: Magnetometer - powering it via multiple sources?????

Posted: Fri Mar 27, 2020 12:30 am
by maniago
GRT_Jeff wrote:If you have a Dual AHRS then there is only one mag power connection there. One Dual AHRS and one Mini would be two power outputs.

I think I will have to get some advice from the engineer on this. Switching the grounds sounds like the safest option. Using a central ground could add noise to the system or drop the voltage level. Definitely don't connect the ground pins together.

If you don't switch the grounds then what's best changes depending on the main power source. When running off the internal battery it would be best to use the Mini's ground. When not running off the internal battery, a central ground is better than the Mini ground.

The magnetometer power outputs are diode-protected so in theory you could connect them together without a switch, but I'm not sure that's a good idea and you still have the ground issue.
Jeff,
I do have the dual adahars, so I'll have to go back and look at those line diagrams to refresh my memory. But yeah, that would then be two power sources, which is much easier to switch power and gnd in one switch. And I think that would cover the redundancy I'm after.

If you can get me a take on the gnds, that would be good as not switching the gnds gives me a smaller switch and I'm realestate deficient for mod right now. Eliminating the switch entirely with the diod protected outputs and ganged gns would be da bomb.....if it was possible. A "no operator input required" solution.

Thanks for any more guidance you might have on this.

Re: Magnetometer - powering it via multiple sources?????

Posted: Wed Apr 01, 2020 3:02 pm
by maniago
Jeff,
Any word from the engineer on what to do here? Can I gang the power inputs and just switch the gnds? Or gang them all with no switch required?

Thanks

Re: Magnetometer - powering it via multiple sources?????

Posted: Tue Apr 07, 2020 12:10 am
by GRT_Jeff
The engineer says you can just connect the power outputs together because they have internal diodes and you don't need to switch grounds. He didn't comment on if any ground would be best but I would try a central ground near the Mini.

Re: Magnetometer - powering it via multiple sources?????

Posted: Tue Apr 07, 2020 12:13 am
by maniago
GRT_Jeff wrote:The engineer says you can just connect the power outputs together because they have internal diodes and you don't need to switch grounds. He didn't comment on if any ground would be best but I would try a central ground near the Mini.
Okey doke. I'll press forward with no switch. If he does comment on the gnds pls let me know. Thanks a bunch!

Re: Magnetometer - powering it via multiple sources?????

Posted: Fri Apr 10, 2020 8:26 pm
by maniago
maniago wrote:
GRT_Jeff wrote:The engineer says you can just connect the power outputs together because they have internal diodes and you don't need to switch grounds. He didn't comment on if any ground would be best but I would try a central ground near the Mini.
Okey doke. I'll press forward with no switch. If he does comment on the gnds pls let me know. Thanks a bunch!

Jeff, I find I'm hesitant to hook this up without clear guidance on the gnds. Can you ask the engineer what the best electrical solution is please? I'd like to just keep using the Mini-X''s gnd as its less wires to fool with, but I'll do whatever he suggests.

Thanks!