Installation document EMS pin assignment reccomendations

[cbretana]

In the installation document, EMS 220 chapter, (on page 7-73), you recommend that a carburetor temperature sensor be connected to pin 23.

However, if someone wishes to install two capacitance type fuel level sensors, the document specifies, ( on page 7-61), that only pins 8, 22, 23 or 31) support this.

Unfortunately, pin 8 is designated to be used for fuel pressure, and pin 31 does not have a wire in the DB37 wire harness.

That means I either need to add another pin & wire to the DB37 harness, or rewire either the fuel pressure or carburetor temperature sensor to another unused GP pin.

Why, specifically does the installation document recommend pin 23? Since it is one of four pins capable of being used for capacitance type fuel level sensors, unless there is some specific reason for the pin 23 recommendation, why not recommend some other GP pin for the carb Temp sensor?

 

[maartenversteeg]

There are a number of EMS inputs that have very specific functions like the fuel-flow sensor pulse inputs, the 30 V inputs, rpm inputs etc. But basically each of the A, B and C category inputs may be swapped, between the specific sensor functions (meaning you can freely swap between any A type inputs etc.). And then in your input specifications you assign each of the inputs pins to the specific measurement / sensor function and the displays will show them accordingly. Dynon provides a set of default assignments that they suggest as a possible setup. But if you as a builder want to swap between the left and right fuel level sensors you are free to do so and if you fill out the pin/channel definition files correctly all will end up on the proper place on the display. Also if you (partly) stick with the defaults provided by Dynon then there is less configuration file editing work to be done.
So if the document specifies pin 23, then this is just a suggestion and you can move this function to a different pin of the same category and in some cases you can move it to a pin of a different category, depending on the electrical characteristics of the sensor. Dynon, can't provide an exact match for each uniquely build aircraft.

 

[Dynon]

Yep, what Maarten said. We have some demi "standardized" pin mappings which let you use the color matched wires on the pre-fabbed EMS harnesses that come with our EMS kits. But you can swap them around with other pins/wires of the same class, as outlined above. Underneath it all, different pins have different electrical measuring capabilities, and that's what the groupings and types are all about.