Using EMS input 23 ( General Input Type C) for detection of Fuel Pump Running

R

RV7Builder

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Hi, i woul like to have an indicator in my HDX when the fuel pump is switched on.
For this i have a free signal input on my EMS. PIn 23 is an IO ( Type C) with voltage measuring.

My question is, Do i have to protect the input Pin from voltage spikes ( f.e. when switching the pump off), with some protection circuit ( RC filter) or can i put the signal direct to the EMS?

nice Greetings David
 
Unless your voltage can spike over 30 volts, and I don't see how it could, it shouldn't be needed. It's rated to handle spikes that high. Depending on how it's connected, you may need a pull down resistor though. That's discussed in this thread:

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

I have scoured book, setup in Skyview, and forums. I cannot figure out where I turn off pull up voltage. Please either reference the exact page of manual or just tell me. This is for my HYD 12v sense line. ie, ON it will send 12v (see 5v) to EMS. Right now it in data debug it shows...
forum.flydynon.com forum.flydynon.com
 
Hi thank You very, much !
I need a Digital Value "Pump ON" when i have 12 V on the Pump Power source., so i think Pin23 should be fine. As i will connect it to the pump Supply line i won´t need a pull down Resistor. I think for safety reasons i will put addional resisitor.
nice Grretings David
 
The EMS is not happy with signals that exceed 5V. Here is what I did.

1764173410291.jpeg

 
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I use to have a small LED on the panel that would illuminate when my boost pump was on. It was on the periphery of my vision and was frequently ignored. When I upgraded my system to Skyview HDX I created a digital indicator and placed it directly beside my RPM gauge. Now it’s always in my primary line of vision and is difficult to ignore. Well worth the effort.

1764261062569.png

Notes:
Contacts
Contacts may be connected to any general purpose input pin on the SV-EMS-220/221’s D37. The number of contacts in your SkyView system is only limited to the number of unused general purpose input pins on the connector.

Contacts are used for a variety of purposes, such as monitoring canopy closure. The EMS Software reads the voltage state of general purpose inputs. To configure them as contacts, use two voltage ranges in your sensor setup. Set one to 0-2V, and the other from 2-5V. SkyView will then 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). You must ensure that when closed, the contact connects to a ground common to the SV-EMS-220. Generally, the voltage on the general purpose inputs should not exceed 15 volts, but the inputs are protected against spikes up to 30V. Generally, it is safe to connect a general purpose input up to any 12V electrical signal (such as monitoring whether power is connected to a 12V fuel pump), but the same is not true for a 24V aircraft – connecting 24V (continuous) to a general purpose input will damage the input.
General purpose input pins are 0 to 5 volt inputs. While higher voltages are tolerated, the voltage will not read higher than 5 volts. Therefore, only use voltages between 0 and 5 volts in your sensor setup.
 
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I would like to know how to build a Skyview widget to show the status of my pitot heat circuit, similar to your fuel boost pump icon. Several years ago I spoke to Dynon tech support about this but was told it couldn't be done - I don't remember what their reason was.
 
The GP inputs are on-off only. They don't have the ability to verify a circuit status beyond on-off. The EMS already monitors heated AOA/pitot status on D37 pin 9, so I'm not sure what you're getting at. It's designed to power a light, but page 3-6 of the Heated and Unheated AOA/Pitot Probe Installation Guide details how to use it on a general purpose input too.
 
Thanks Rhino. Since I didn't build the plane or assemble the panel, I didn't know that pitot installation document existed. I'm not sure why Dynon tech support didn't think I could add a Pitot Heat On/Off widget when the instructions are clearly detailed in the guide you mentioned.
 
Rhino said:
The GP inputs are on-off only. They don't have the ability to verify a circuit status beyond on-off. The EMS already monitors heated AOA/pitot status on D37 pin 9, so I'm not sure what you're getting at. It's designed to power a light, but page 3-6 of the Heated and Unheated AOA/Pitot Probe Installation Guide details how to use it on a general purpose input too.
Click to expand...
The GP inputs of the EMS (#1-13, pins 4, 22, 23,8, 9, etc.) are analog input channels that can measure analog voltages withing a range from 0 to 5 Volt. There are mainly three different groups A, B and C, with different capabilities but these channels all result in an analog measured value that may interpreted differently depending on the specified conversion factors (specified in the configuration file). In addition there are four contact inputs The four contact inputs are limited in that these can't be assigned fully random functions and limits. These four contacts sensors are per-assinged by Dynon with special functions like: 1: Level button, 2: Go Around button etc.
 
I'm well aware. But he was talking about circuit status, not a measurement.
 
Rhino said:
I'm well aware. But he was talking about circuit status, not a measurement.
Click to expand...
But he mentioned pin 23 at the EMS which he stated was unused in his design. If he makes sure that the 5 Volt maximum input voltage of the EMS is not exceeded then this should work fine as an indication of the fuel pump being powered. Either limit the voltage with a diode or include a voltage divides that keeps the voltage below 5 Volt and all shoudl work without issues.
 
Yes, he mentioned pin 23 for circuit status. I answered the question in the context in which it was offered. I don't see the problem with that. And 5 volts is not the maximum. 15 volts is, with brief surges up to 30 volts. 5 volts is just the highest voltage it will measure.
 
Hi together thank you very much for all your responses. Yes I was not completely correct maybe because of my English. I wrote measuring but didn't mean that . What I need is a detection if the pump is on (12V) or off (0V). And this will work with an GPIO pins. The measurement is not necessary. I will try using a 10 k Resistor as protection needed or not.

Thank You very much for all comments and tips.

DAVID
 
Check put this post on sensing switched inputs:

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

I have scoured book, setup in Skyview, and forums. I cannot figure out where I turn off pull up voltage. Please either reference the exact page of manual or just tell me. This is for my HYD 12v sense line. ie, ON it will send 12v (see 5v) to EMS. Right now it in data debug it shows...
forum.flydynon.com forum.flydynon.com

A more refined diagram is here: EMS Wiring
 
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