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Transponder/EFIS Gray code

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dean.psiropoulos(at)veriz
Guest

Posted: Fri Feb 24, 2006 8:15 pm Post subject: Transponder/EFIS Gray code

Thanks for the help Brian, I think you mis-understood my question on the

Gray Code connection to the transponder.  You are correct that the SL70 has

both Gray code and serial encoder inputs.  But.....my EFIS D10 is an

original production model and does NOT have an encoder serial data OUTPUT

like the newer EFIS D10-A model.  So I have to use the Gray code signals out

of the EFIS to drive the transponder.  The EFIS has "A", "B" and "C" Gray

code signals (out) which correspond to the transponder Gray code inputs with

one exception.  The Transponder has one additional Gray code input labeled

"D4" but the EFIS does NOT have a "D4" output (I assume this extra input

allows the Transponder to encode and transmit higher altitudes than those

with just A/B/C inputs).  In any case, my question is what to do with this

"D4" input at the transponder end.  Is it ok to leave it unconnected

(floating) or do I need to connect it to a positive voltage or...to ground?

Can't find any direction in the manual so I assume leaving it float will not

cause a problem but would really like to know for sure.  Sorry for the

initial confusion.



Dean Psiropoulos

RV-6A N197DM 

Autocad-only the Radio Stack remains



----------------original message-------------------------

 	  Quote: 	
		  From: Brian Lloyd <brian-yak(at)lloyd.com>

Subject: Re: Transponder/ RS-232


	


 	  Quote: 	
		  I don't remember if the SL-70 accepts serial data in instead of gray code.

I *think* it does but I am not sure. If it does not you will need a

serial->to-grey-code converter to get the data from the Dynon to the
	


SL-70....

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mthomson(at)showmeproduct
Guest

Posted: Fri Feb 24, 2006 8:45 pm Post subject: Transponder/EFIS Gray code

 	  Quote: 	
		  From my experience with other EFIS and encoder systems, just leave

unconnected.  Your assumption is correct and it is used only for higher
	


altitudes.

--

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brian

Joined: 02 Jan 2006
Posts: 643
Location: Sacramento, California, USA

Posted: Sat Feb 25, 2006 9:11 am Post subject: Transponder/EFIS Gray code

DEAN PSIROPOULOS wrote:

 	  Quote: 	
		   

 

 Thanks for the help Brian, I think you mis-understood my question on the

 Gray Code connection to the transponder.  You are correct that the SL70 has

 both Gray code and serial encoder inputs.  But.....my EFIS D10 is an

 original production model and does NOT have an encoder serial data OUTPUT

 like the newer EFIS D10-A model.  


	


Ah, you are correct. I was thinking that the D10 had serial but not grey

code output. It is all a matter of listening to the question. 



 	  Quote: 	
		   So I have to use the Gray code signals out

 of the EFIS to drive the transponder.  The EFIS has "A", "B" and "C" Gray

 code signals (out) which correspond to the transponder Gray code inputs with

 one exception.  The Transponder has one additional Gray code input labeled

 "D4" but the EFIS does NOT have a "D4" output (I assume this extra input

 allows the Transponder to encode and transmit higher altitudes than those

 with just A/B/C inputs).  


	


Correct. It adds one more data bit in addition to the 9 bits you already

have. It allows altitudes above 25,000'.



 	  Quote: 	
		   In any case, my question is what to do with this

 "D4" input at the transponder end.  Is it ok to leave it unconnected

 (floating) or do I need to connect it to a positive voltage or...to ground?


	


The transponder already has the necessary pull-up resistor at its input

so that if you don't connect the D4 input, it will automatically default

to a zero.



 	  Quote: 	
		   Can't find any direction in the manual so I assume leaving it float will not

 cause a problem but would really like to know for sure.  Sorry for the

 initial confusion.


	


No problem.

-- 

Brian Lloyd                         361 Catterline Way

brian-yak at lloyd dot com          Folsom, CA 95630

+1.916.367.2131 (voice)             +1.270.912.0788 (fax)



I fly because it releases my mind from the tyranny of petty things . . .

- Antoine de Saint-Exupery

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_________________
Brian Lloyd
brian-yak at lloyd dot com
+1.916.367.2131 (voice) +1.270.912.0788 (fax)

I fly because it releases my mind from the tyranny of petty things . . .
- Antoine de Saint-Exupery

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