EMS Contact Function

[dodsond]

How do these circuits work? Does the state change only for open and short to ground or can I connect a low power device to them?

I am asking becasue the Plasma III ignition system has a 5v, 50ma output that is used to power an LCD display. In a dual system, it can be used to indicate when one system is powered and the other isn't. This is done by connecting the output of system one to the output of system 2 through a pair of LEDs. Neither LED is on if both systems are powered or both unpowered. If only one system is powered, then one of the LEDs is illuminated. I have attached a .pdf with the diagram.

I am wondering if it is possible to use the Plama III output on an EMS contact to provide the same function.

Doug Dodson
Glasair II-S FT

 

[dynonsupport]

These are high impedance digital inputs with a 10K pullup to 5V.

So they are 5V unless you hook something to them. Normally this is a switch to ground, so they are 5V or 0V.

From the looks of that diagram, it outputs 5V when in one state and ground in another. This is exactly what we want and should work well.

 

[19fx57xl106]

How do I connect a contact up with a Facet electric fuel pump to indicate on / off

 

[mmarien]

Check to see if the positive terminal on the pump shows a drain to ground with the power off. If it does then connect the EMS contact pin wire to the positive terminate on the pump or any point downstream of the ON/OFF switch for the pump. When the power to the pump is OFF EMS will see 0-2V. When the power is turned ON the EMS will see 2-5V.

See this thread: http://dynonavionics.com/cgi-bin/yabb2/YaBB.pl?num=1321300594

 

[Dynon]

This thread has some good information on how you can connect devices to contact inputs.

 

[19fx57xl106]

If you mean is there continuity between the power wire and ground, then there is not.
The fuel pump is not wired into the system yet if that makes a difference.

 

[mmarien]

Then you will have to add the resistor as noted in the thread mentioned above.

Skyview normally reads +5V on the EMS pin when it is NOT grounded. It read 0V when it is grounded. That is the normal way to use the contact. In your case (and mine from the thread) we want to detect when the device has power. We need to connect the EMS pin to ground so that it normally reads 0V. Then when you apply power to the pump it will read +5V. It can handle up to +15V but only reads a maximum of +5V.

If the pump would have a drain to ground on the positive pole it would work without the resistor. Adding the resistor will connect the EMS pin to ground when the pump is OFF. If you use a 1/4 watt 1K resistor when you add power there is so little flow through the resistor (1/4 watt) that it makes no difference to the operation on the pump.

I would just add the resistor from the positive pole to the negative pole right on the pump. The EMS pin wire can then be connected to anywhere downstream of the power switch for the pump.

HTH

 

[19fx57xl106]

Thanks for clearing that up for me Murray, I understand it now.