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Help with Wiring Flap Sensor to Dynon EMS

PhatRV

Well Known Member
I have a Ray Allen flap position sensor and I need to help on how connect the 3 wires on the sensor to the Dynon EMS. The picture below shows the wiring diagram of the Ray Allen position sensor and the the Dynon EMS wiring to a generic flap sensor.

My question is the EMS diagram only shows 2 connections, one from the sensor wire (Green) and Ground wire. On the Ray Allen it doesn't show the ground wire or power wire. From the picture below, can you tell me which wire goes to where, and does it mean one of the 3-wires on the Ray Allen sensor is not connected?

Thanks.
 

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The Dynon EMS can be configured with an internal pull-up to 5V. This allow just two wires to be connected to the sensor... one to ground and the other (middle or wiper) to the EMS.

The alternative way is to use 3 wires. One to the sensor +5V supply from the EMS, one to ground and the middle one to the EMS input. In this case the EMS must be configured without the pull-up.

Either way, calibration must be performed.

V
 
Does it matter if I wire the Orange or the Blue wire to Ground if I choose to use 2 wires into the EMS?

Thanks.
 
Does it matter if I wire the Orange or the Blue wire to Ground if I choose to use 2 wires into the EMS?

Thanks.

not as long as the dynon has a config setting for reversing the direction of the sensor input. If not, you need to figure which wires give the proper direction (up = 0v or up = 5v) for the direction desired for the display.

Larry
 
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So is there a way to test which wire is the correct wire?

And how to test it? without plugging it into the Dynon EMS module first?
 
So is there a way to test which wire is the correct wire?

And how to test it? without plugging it into the Dynon EMS module first?

Connect it up, calibrate and observe the readout during flap activation. If it doesn't report in the correct direction, either reverse it via software, if available, or swap the orange and blue wire connections. Likely the reversal is part of the calibration process. I don't have a dynon system, but would be surprised to find that it can't reverse the input.

Hard to give you a test, as I don't know if Dynon treats 0 volts as full up or full down. With the slide all the way in, one wire will give around 100-500 ohms when measured across the green wire (reports as 5 volts) and the other wire will give 10,000 ohms (reports as 0 volts). They reverse with the slide all the way out.

Larry
 
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I search the Dynon old EMS document and it says something about the blue/white wire on the older Ray Allen sensor. I will call Dynon to confirm
 
Update from Ray Allen and Dynon Support

I called the support at Ray Allen and Dynon today. The flap sensor must have all three wires connected. Either the Orange or Blue wire must be Ground and the other must be wired to a 5V reference source. The Green is the sensor. Dynon instructed to use the Pin18 on the EMS 37pin connector as the 5V reference source.
 
You don't have a flap controller do you? If so the wiring may be different. I have the flap controller from Aircraft Extras and the POS-12 hooks up to the controller and then it sends an output to the EMS on one wire.
 
I called the support at Ray Allen and Dynon today. The flap sensor must have all three wires connected. Either the Orange or Blue wire must be Ground and the other must be wired to a 5V reference source. The Green is the sensor. Dynon instructed to use the Pin18 on the EMS 37pin connector as the 5V reference source.

Well, I have a sensor with only two wires. I made a custom EMS config file that enables an internal pull-up. Calibrated it and works fine.
 
You don't have a flap controller do you? If so the wiring may be different. I have the flap controller from Aircraft Extras and the POS-12 hooks up to the controller and then it sends an output to the EMS on one wire.

I have a stand alone POS-12 flap sensor instead of the integrated one in your newer flap motor. Perhaps your integrated sensor already has the necessary reference voltage. As explained by the support person in Ray Allen, the device must have a 5V reference source. I reread the Dynon Skyview last night and it has a section that describes how to get the 5V reference voltage from pin18. I wish Dynon had published that info with the wiring diagram because it was easy to miss the one sentence that describes this 5V source.
 
I have a stand alone POS-12 flap sensor instead of the integrated one in your newer flap motor. Perhaps your integrated sensor already has the necessary reference voltage. As explained by the support person in Ray Allen, the device must have a 5V reference source. I reread the Dynon Skyview last night and it has a section that describes how to get the 5V reference voltage from pin18. I wish Dynon had published that info with the wiring diagram because it was easy to miss the one sentence that describes this 5V source.

I have the stand alone POS-12 as well. All three wires are hooked up to my flap controller and then there is a wire going from the controller to the EMS. If you don't have a flap controller then no worries.
 
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