Wiring resistive fuel level senders

[Tuiliere]

Hello,

working on my EMS 220, I saw I have to connect my resistive fuel level senders to the PIN 20 (left sender) and 21 (right sender). Can you tell me where I have to connect the ground ? Directly near the sender on the wing, or on my Ground terminal, or on a EMS ground black wire ?

In advance thank you
Sylvain

 

[Dynon]

Any of those work IF the ground out at your wing is the same ground as your EMS. With metal airplanes, the airframe is usually fine.

 

[dynonsupport]

In our experience, one terminal of a resistive fuel level sensor is usually already grounded to the airframe (only one terminal is exposed to be connected). If you do have access to the second terminal of a resistive fuel flow sensor, connect it to one of the grounds available on the SV-EMS-220/221 - any of pins 3, 5, 13, 16, 17, or 30 (Black wires).

Hello,

working on my EMS 220, I saw I have to connect my resistive fuel level senders to the PIN 20 (left sender) and 21 (right sender). Can you tell me where I have to connect the ground ? Directly near the sender on the wing, or on my Ground terminal, or on a EMS ground black wire ?

In advance thank you
Sylvain

 

[Tuiliere]

Thank you for your fast reply.

Nice day !
Sylvain

 

[dbwindom]

If using a VP-X system, is the Org/Brn or Org/Blu wires from EMS pins 20 & 21 even used? I've already pulled a wire from my VP-X out to my wing root, so I'm a little confused, now that I'm wiring FWF, and found these EMS wires in my harness.
Same confusion with the Heated Pitot status wire from EMS pin 9. I have my heated pitot switch through my VP-X.

Thanks.

 

[jakej]

AAflyer

Resistive sensors - Yes, use the EMS wires for the required functions as per install manual. NO power required. Pitot Status wire goes to a 'contact' function in the EMS & same reference applies.

Capacitive Fuel sensors - use pins as decribed in the manual & the power can be spliced into the Fuel Flow wire (it's a 12vlt regulated source) so no need to connect this to vp-x at all & I wouldn't.

Jake J

 

[dbwindom]

Jake,
Thanks for your help.
Ok, so to be clear, the wire from my VP-X to my Stewart-Warner float-type fuel sender, should NOT be used.  Instead, the Org/Blu and Org/Brn wires from the EMS should be attached to the big terminal in the center of the sender's round  plate? I thought that these types of senders should have some voltage running through them in order to register 'resistance' and thereby produce measurable data to use in displaying proper fuel quantities. 
Perhaps my confusion is that I'm unsure if the wires from the EMS are power, or data lines.
Would I still need to run a ground wire from each sender?

Also…as you can probably tell, I'm no electrical engineer…Your advice about the pitot heat; I am confused about "Pitot Status wire goes to a 'contact' function in the EMS & same reference applies." This wire currently is pinned at pin 9, Brn/Blu, and according to the chart titled "Example Lycoming/Continental 4-cylinder Fuel Injected (SV-EMS-220)" on page 7-13 of the Dynon install manual, is dedicated to; "Heated pitot status (contact input)".
So, as far as I can tell this wire ALREADY IS connected to a "contact function", ….it's the OTHER, UNCONNECTED end I need help with. Should it be connected to the pitot heat switch, or should I splice it into the power wire coming from the VP-X out to the pitot tube, or…????

The fog is only getting thicker... :-?

 

[jakej]

Fuel level sensors (float type) The wires from the EMS module should go direct to the sensor, they measure resistance - DO NOT connect to power or you will have an explosive event.
You can connect a ground wire to the sensor however the airframe is a suitable ground as the body of the sensor is screwed to it anyway 

Pitot heat status - there are 3 wires at the heater module, 1 X red (power from VP-X), 1 X black = ground. Plus the 1x White which is connected to the pitot status (contact) wire.

HTH

Jake J

 

[mmarien]

I thought that these types of senders should have some voltage running through them in order to register 'resistance' and thereby produce measurable data to use in displaying proper fuel quantities.

They do in a sense. If you have an ohm setting on your multi meter you can see whats happening. Set the meter to ohms and touch the contacts together. You should get a reading of 1.0. Connect the meter contacts to any two wire resistance type sensor, fuel/EGT/CHT/oil temperature and you will get less than one. It's just measuring the resistance of the sensor. That is what the EMS is doing. No power needed. The resistance varies with the temperature or level.

Should it be connected to the pitot heat switch, or should I splice it into the power wire coming from the VP-X out to the pitot tube, or…????

Do you have the Dynon heated pitot?

 

[dbwindom]

Ooooohhh…
Thanks for the lesson on resistance sensors.

Yes, I have the Dynon heated pitot/AOA probe.

 

[dbwindom]

Fuel level sensors (float type) The wires from the EMS module should go direct to the sensor, they measure resistance - DO NOT connect to power or you will have an explosive event.
You can connect a ground wire to the sensor however the airframe is a suitable ground as the body of the sensor is screwed to it anyway 



Pitot heat status - there are 3 wires at the heater module, 1 X red (power from VP-X), 1 X black = ground. Plus the 1x White which is connected to the pitot status (contact) wire.

HTH

Jake J

Fuel level sensors (float type) The wires from the EMS module should go direct to the sensor, they measure resistance - DO NOT connect to power or you will have an explosive event.
You can connect a ground wire to the sensor however the airframe is a suitable ground as the body of the sensor is screwed to it anyway 

Pitot heat status - there are 3 wires at the heater module, 1 X red (power from VP-X), 1 X black = ground. Plus the 1x White which is connected to the pitot status (contact) wire.

HTH

Jake J

Ahhh Sooo…
Thanks Jake for your patient tutelage.
B.