For whatever reason I can not wrap my head around how my TO/GA switch should be wired or even what it does. I think it goes to momentarily ground? It’s a Steinair TO/GA switch. Any help would help me move along on my panel wiring. Thanks!
Thanks Bob. I am trying to figure out if the switch grounds both inputs out at the same time. I got 3 wires to attach and one jumper to ground, but which lugs do the wires go to?There was a thread on this, I think.
It is a DP switch because there are two separate circuits.
One goes to the GMC507 and I think the other is for the navigator...both are momentary ground when the button is pressed. At least that's how my diagram says it's wired...
It should give you TOGA pitch and roll on your PFD and the one connected to the GTN sequences the missed approach...
There was a thread on this, I think.
It is a DP switch because there are two separate circuits.
One goes to the GMC507 and I think the other is for the navigator...both are momentary ground when the button is pressed. At least that's how my diagram says it's wired...
It should give you TOGA pitch and roll on your PFD and the one connected to the GTN sequences the missed approach...
Thanks Bob. I am trying to figure out if the switch grounds both inputs out at the same time. I got 3 wires to attach and one jumper to ground, but which lugs do the wires go to?
Yes, there was a thread on connecting both to one terminal. I seem to recall that the Garmin Expert had some reason for not connecting the two wires together...
I have a GTN 650 with a 307. The drawing is from Steinair, as is the TO/GA switch so I assume it it correct. The switch and the 6 lugs is what befuddles me though. I'll get the meter out and start testing I guess.?
Not sure why you have a DPDT switch as opposed to the DPST switch shown on Stein's website, but it should still work fine.
The DPDT switch will have 2 common poles, 2 NO poles, and 2 NC poles. Just wire up the 2 common poles and the 2 NO poles like shown on your wiring diagram.
Steve
Alright,,,thanks everyone. I got it now. I thought I had a DPDT switch but I took another look at Steins website and sure enough,, its a DPST switch!
Adding to the original post's request for "what should it do?," I would add that it should command the flaps to move to take-off position, on aircraft with electric flaps.
Yes. That's what it does in my friend's Rocket.You are just going to confuse the guy. We should talk about what it does.
For an install with a GMC507/GNX375, do they also need a seperate to/ga input via a DPST button? The g3x manual doesn’t really show how this works - only how to wire it with a GTN.
Or can I wire a to/ga button to just the GMC507 autopilot controller and it will let the gnx375 know to go around via canbus or the rs232 connection between the gdu/gnx
I ask as I was considering using the momentary push button on my stick for to/ga. But if it needs to be dual pole, this won’t work. Or, I could use diodes i suppose.
Why does the TO/GA need to go to two devices via a DPST anyway? After all, both the devices would be grounded to the same place anyway. So grounding both TO/GA pins through the same switch to a common ground shouldn’t be an issue?!
Alright,,,thanks everyone. I got it now. I thought I had a DPDT switch but I took another look at Steins website and sure enough,, its a DPST switch!
Typically this is done so that when one device is turned off it doesn't inadvertently pull the input of the other device to ground. Separate switches or a pair of diodes will prevent this.
I still can’t get my head around this tho. Both devices would have their grounds connected. Everything in the aircraft will have the same ground potential!
I don't have the exact internals of the discrete inputs on either of these devices in front of me, but speaking generally from past experience: typically there will be an internal pull-up resistor, which can become a pull-down resistor when the device's power supply goes away.
Thanks Matt.
I searched “diode” at my local electronics shop and there are predictably a lot of results!! The g3x manual doesn’t help much except shows a zener diode and a normal diode used in a rotax install.
Would something like this do the job? (Good for 450ma)
https://www.jaycar.com.au/1n4148-1n914-signal-diode-pack-of-5/p/ZR1100