Need to turn off Pull up Voltage on Pin 22 in EMS

[Rhino]

Actually, I would put the pull down between the series resistor and EMS. It would probably still work the way you have it, but it isn't ideal.

Great. Thanks, Don.

 

[Rhino]

So, this would be the proper configuration for a pull down resistor when an inline (series) resistor is installed. This is applicable to the enhanced type C general purpose inputs (pins 8, 22, 23, and 31) that do not have configurable internal pull ups.

 

[vlittle]

So, this would be the proper configuration for a pull down resistor when an inline (series) resistor is installed. This is applicable to the enhanced type C general purpose inputs (pins 8, 22, 23, and 31) that do not have configurable internal pull ups.

View attachment 5180

The SkyView EMS Enhanced Inputs will work fine with this arrangement. Personally, I would use a 20K resistor connected to the Sensor if it is a 12V source, so that the voltage divider gives 4.75V with a 14.25 volt switched input. This is to prevent overdriving the EMS input. Dynon doesn't want too many of the inputs overdriven or it will mess up the internal bias voltages.

 

[Rhino]

That may well be true with multiple inputs, particularly in a 24 volt system, so good point. I was just using the Dynon recommendation of 10k for the diagram example.

 

[Rhino]

If you'd like to have a synopsis of everything I posted, here's a pdf file.

 

[vlittle]

This is an updated schematic diagram, which more clearly indicates the resistor network that I used for sensing switched +14V signals In this case, power to EMag ignitions and the fuel pump. The pin 9 of the DSUB connects to one of the EMS grounds.

Vern