G3X Canopy Latched Alarm

-- SOLVED (BUILDER ERROR) -- See 2nd to last post

I'm trying to setup a canopy latch alarm on my G3X GDU-370 (Non-touch). I've got the micro-switch setup behind the pin behind the panel. It's been wired with the normally open lead to ground Discrete In 1 on Pin 40 - J244 on GEA 24.

I've tried configuring the channel as a "Canopy Open" alarm with Active Low / High and I can't get it to trigger.

Per the manual...

When configured as Active Low, the inputs conform to the following specification:
Active: Vin < 3.5 VDC, or Rin < 375 Ω
Inactive: Vin > 8 VDC, or Rin > 100 kΩ

When configured as Active High the inputs conform to the following specification:
Active: Vin > 8 VDC, or Rin > 100 kΩ
Inactive: Vin < 3.5 VDC, or Rin < 375 Ω


So... There's no internall pull-up resistor and I need to setup a pull up? Behind this, I can't find any example circuits. Has anyone tried to setup a discrete channel on the G3X?

Thanks!
-Bruce

Hopefully the G3Xperts will respond, but here is an answer from my son who just wired this on our RV-7A after talking to the Garmin folks -

" think you don't on the discretes, however a pull up should work. 5k ohm to the 12v pin 50"

BruceMe said:

I'm trying to setup a canopy latch alarm on my G3X GDU-370 (Non-touch). I've got the micro-switch setup behind the pin behind the panel. It's been wired with the normally open lead to ground Discrete In 1 on Pin 40 - J244 on GEA 24.

I've tried configuring the channel as a "Canopy Open" alarm with Active Low / High and I can't get it to trigger.

Per the manual...

When configured as Active Low, the inputs conform to the following specification:
Active: Vin < 3.5 VDC, or Rin < 375 Ω
Inactive: Vin > 8 VDC, or Rin > 100 kΩ

When configured as Active High the inputs conform to the following specification:
Active: Vin > 8 VDC, or Rin > 100 kΩ
Inactive: Vin < 3.5 VDC, or Rin < 375 Ω


So... There's no internall pull-up resistor and I need to setup a pull up? Behind this, I can't find any example circuits. Has anyone tried to setup a discrete channel on the G3X?

Thanks!
-Bruce

Click to expand...

Bruce, I think you are using the Canopy Closed configuration. If you read the description below (installation manual page 33-130 of Rev AB), the system uses a combination of the discrete input and the engine power setting (RPM) or airborne status to alert. So if you leave the canopy open you should get the basic annunciation of CANOPY OPEN. If you start to accelerate down the runway, or open the canopy in the air, you should get the red warning alert with audio as well.

If you can confirm the pin is open, you should be getting the basic alert. And grounding the pin should make it clear. You might send us the specifics of the switch you are using in case there are some compatibility issues with that particular part. You could also try configuring a custom discrete input and see if you can get your switch to trigger an alert that way. Feel free to contact us directly using the information below so we can get you fixed up.

Regards,
Brian

Canopy Closed - Used with a switch that activates the input when the aircraft canopy is closed and locked. A solid yellow CANOPY OPEN message will appear on the PFD if the Canopy Closed input is not active. If engine power is increased or the aircraft is airborne, the CANOPY OPEN message will flash red and an alert tone will sound.

BruceMe said:

I've tried configuring the channel as a "Canopy Open" alarm with Active Low / High and I can't get it to trigger.

Click to expand...

Bruce, another point to clarify. Do you have the discrete input configured for Active Low or Active High? That will impact the behavior so please double check that setting.

Regards,
Brian

Per 33-130, It should be active-low, but DISC 1 (J244 Pin 40) is acting like a ground. Not sure why. When I'm out next, I'm going to try DISC 3 (J244 Pin 42) which is what is called out in the Vans RV-12 canopy alarm SB.

-Bruce

I think I'm off-by-one. Having a very hard time reading the pins on the connector. I think what I thought was pin 40 (DISCRETE 1) is actually pin 39 (FUEL XDCR GND_4) yeah... that's a ground and what the multi-meter was telling me. Then I dropped one more thinking I was testing DISCRETE 2, but it was really DISCRETE 1 (Pin 40). Repeat for #3... GAH! too many pins.

--- SOLVED ---

Exactly what I said in my last post... off by one pin

That's it. Canopy alarm works nicely when it's wired.