EMS D 37 contact pins.

[cbretana]

I already have a landing gear warning light system in my Long EZ, containing a microswitch on the nosegear, an airspeed switch and a microswitch on the throttle. It is set up so that the light comes on when airspeed is below 80KIAS, throttle is below 50%, and the nose gear is not fully extended. The three switches are in series with the warning light with the other end of the warning light attached to ground, and the switch on the other end hooked up to the 12 volt bus.

Can I attach another wire from the end switch near the 12 volt bus to one of the contact pins on the EMS to display a warning light using the same logic and the same switches on the HDX display screen?

 

[djones]

You can connect a GP input from the EMS to the switch side of the light bulb. (if you want to mimic the light bulb) Put a 10K resistor in the EMS wire, configure the pin in sensor input mapping as a CONTACT, set the voltage ranges in sensor setup and create widgets for it on the EMS screens you want to see it on. Should work fine.

 

[cbretana]

Don,

Thanks much for this... I was worried about the fact that my circuit is connected to the 12 volt bus. I would never have come up with the 10k resistor idea on my own.

Now just to make sure we are on the same page, may I ask this....
If I connect things as I think you are suggesting, the sequence of things in my setup would be
12V bus <-> CB <-> 3 Microswitches <-> Warn light <-> attached wire 2 EMS <-> Acft Grnd.

So with this sequence, even when one of the microswitches is open (warning light would be out), the wire to the EMS would still be connected to ground. In the install manual on bottom of page 7-71 it says "Skyview will report whether each input is open (no connection to ground, which is the 2-5V state) or closed (connection to ground, which is the 0-2V state)."

So if I connect to the EMS pin from the switch side of my light bulb, then it will always be "connected" to ground, (through the light bulb), no matter whether the microswitches are open or closed. This makes me suspicious that I am not understanding something....

 

[djones]

No, the EMS connection needs to be on the switch side of the light bulb.
12V bus <-> CB <-> 3 Microswitches <-> attached wire 2 EMS <-> Warn light <-> Acft Grnd.

 

[cbretana]

Okay, got it... Then the voltage at the EMS wire will be aircraft bus voltage when the three microswitches are closed, but it will be zero V (connected to ground through the Warn light) when the any of the three switches are open...

Thanks!

Charly

 

[cbretana]

Just for clarity, to use a GP input as a contact sensor, I should wire it from the 12V aircraft power bus, to a microswitch, (like a canopy closed switch), and then to one of the EMS contact input pins?