Contact Sensors Power source - need for 1k Ohm resistors

[cbretana]

On page 7-79 of the Installation manual, (I have revision AU), it states:

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. The voltage on the general-purpose inputs should not exceed 5 volts, but the inputs are protected against spikes up to 30V. If a general-purpose input is used to monitor a voltage above 5V, such as monitoring whether power is connected to a 12V fuel pump, a 10 Kilo-ohm resistor in series with the positive voltage sense wire must be installed.

I am trying to hook up retractable Landing Gear status indicators. My aircraft uses 1 14 volt main battery bus. Obviously, the db-27 connector on the SV-EMS-220 has a 5 volt output lead (pin 19 I believe) which I could use for the three microswitches that will detect whether the gear is fully extended, Down & Locked-over-center). Is that the recommended approach, or should I use wire these contacts from a lead directly off the 12/14 volt main avionics bus with an inline 10k ohm resistor ?

 

[Rhino]

Use the 5 volts. The general purpose contacts can take spikes up to 30 volts if needs be, but they are designed to only use up to 5 volts in normal operation.

 

[Rhino]

This might also be of some help as far as how those pins work. Ignore the stuff about relays.

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

 

[cbretana]

Rhino, Thanks. I suspected as much, but wasn't sure.