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  #1  
Old 05-21-2021, 02:24 PM
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Larco Larco is offline
 
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Default Dynon servo wires

Wanting to change from TruTrac servos to Dynon SV servos. Question is, I want to use the existing wires to/from the TT servos and changing pin position instead of changing to the dynon harness. I have an AFS 5500 EFIS system. I ask because the dynon harness has a pair of twisted wires and the TT does not. I did not use the twisted wire harness when changing to the dynon SV Adahrs and it worked out fine so want to save lots of time and some money when I do the change to the dynon SV servos. Thanks
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  #2  
Old 05-21-2021, 02:42 PM
PhatRV PhatRV is online now
 
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I think Dynon sends the serial signals through the twisted pair wires, but at least there is no shielding required; because of the low baud rate?

If you are have success at using the Dynon ADHARS using straight wires, you can try to reuse the existing straight wires and see if the servo will be affected by the noise. If it is, you can create the twisted pair wires like I did using a drill.
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  #3  
Old 05-21-2021, 02:44 PM
StephenC StephenC is offline
 
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The purpose of twisting is to reduce electrical interference to a minimum. As I recall the harness supplied for the RV12 does not use twisted pairs but might not have looked closely enough to see the twists.
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  #4  
Old 05-21-2021, 02:45 PM
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nzrv8 nzrv8 is offline
 
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Hi Larry,

Twisted pair for data wiring is important for various reasons . Yes, often you may notice no difference if you don't twist the wires, but that doesn't mean its correct, and also doesn't mean you won't have intermittent glitches. For a robust data bus, especially in automotive/aircraft applications, the wires must be twisted.
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  #5  
Old 05-22-2021, 07:32 AM
lr172 lr172 is offline
 
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Quote:
Originally Posted by nzrv8 View Post
Hi Larry,

Twisted pair for data wiring is important for various reasons . Yes, often you may notice no difference if you don't twist the wires, but that doesn't mean its correct, and also doesn't mean you won't have intermittent glitches. For a robust data bus, especially in automotive/aircraft applications, the wires must be twisted.
+1

I wouldn't do it unless I had instruments to back up the EFIS. The servo run is likely much longer than the AHRS run. The spec calls for twisted wire for a reason. It is not just conservative nonsense. You may not have problems, but will be far more likely to have them then those who install it to spec. Don't forget that is a common bus and all devices broadcast on the same bus, so if you pick up noise on the servo run, it will telegraph through the whole bus and create problems for every device on that bus.

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Last edited by lr172 : 05-22-2021 at 07:35 AM.
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  #6  
Old 05-22-2021, 07:45 AM
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RicoB RicoB is offline
 
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I am going thru the same upgrade from the trutrac servos to the dynon servos, I keept the existing wires, they are not straight runs, the whole bundle is twisted. I will find out. if doesn't work then I can change the wires, but i think it will be just fine.
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  #7  
Old 05-24-2021, 05:48 PM
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Larco Larco is offline
 
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Thanks for all the replies. I am still on the fence regarding the up grade and all the input is helpful and appreciated.
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  #8  
Old 05-24-2021, 07:19 PM
RV10Pilot RV10Pilot is offline
 
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Quote:
Originally Posted by RicoB View Post
I am going thru the same upgrade from the trutrac servos to the dynon servos, I keept the existing wires, they are not straight runs, the whole bundle is twisted. I will find out. if doesn't work then I can change the wires, but i think it will be just fine.
I have the Stein servo wiring that was originally for TruTrak servos. It is now being used for my Dynon servos. It is a twisted bundle. The servos have worked flawlessly since first flight that was 8 months ago.
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