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

RV7Builder

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Dec 9, 2020
Messages
37
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
 

Rhino

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Jul 20, 2009
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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:

 

RV7Builder

Member
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Dec 9, 2020
Messages
37
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
 

vlittle

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May 7, 2006
Messages
549
The EMS is not happy with signals that exceed 5V. Here is what I did.

1764173410291.jpeg

 
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MikeD

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May 14, 2023
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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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andresmith76

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Oct 4, 2018
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179
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.
 

Rhino

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Jul 20, 2009
Messages
1,739
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.
 

andresmith76

I love flying!
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Oct 4, 2018
Messages
179
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.
 
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