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GRT Mini AP wiring to Echo UAT/SafeFly 2020 Issue

scott08

Active Member
I've been looking for an answer for approximately 2 hours and have found little to no help. The manual for the Safefly 2020 from GRT is honestly junk. It says a few contradicting things. First it says to directly wire the ADSB input to a high speed serial connection (The Mini has 2 open serial connections per the manual). The SafeFly installation claims to have serial port combiner functions, but it goes to say that the AP servos should be wired directly to the EFIS for latency concerns. So direct wire for AP servos, direct wire for ADSB input, then how does the combiner connect to the Mini X when all available serial ports are used?

My dilemma is this, On my Mini X I have serial 2 open In/Out (Serial 1 is used by the AP Servos), I need to use that for the ADSB in from the SafeFly, but then that leaves me no open serial ports for the SafeFly GPS input, serial combiner, and controller functions for the EchoUAT. Can anyone shed some light on this? GRT support has been difficult to get a hold of due to the reduced hours.

Thanks,
Scott
 
GRT help

I have gotten good answers from GRT by sending an email to Jeff,who often works in the evening. His explanations have been understandings o my limited knowledge of wiring.

Good luck,
 
In a nutshell, you can?t get there from here. ADS-B in and serial in/out from the SafeFly require 115k baud. IIRC the serial out line for autopilot servo control requires 9600 baud. So the open remaining ?out? port does you no good- though from what you wrote it sounds like you understand that. The Mini A/P technically has 3 serial ports, though one is consumed by the external magnetometer (guessing you know that too). What it needs is 4 serial ports. 3 just isn?t sufficient for standalone use.

I suppose what I would do in your case is to connect the servos to one of the open spc ports on the SafeFly and see just how bad the latency is.

I have said Mini AP, the SafeFly and a Sport SX with 5 ports. Even that combo caused me to do some creative juggling to connect everything.
 
So there was a solution that makes it work correctly. The magnetometer get rewired to the safe fly/serial combiner that gets wired to serial 3 (where the magnetometer was wired in). When you tell serial port 3 it is connected to the GRT safefly/spc 3 additional serial ports come up and can be configured for the magnetometer. Grt then graciously gave me the ADSB feature set as my mini ap was an early model that didn't have it. Grt has been very helpful in getting things figured out.

  • serial 1 - autopilot servos
  • serial 2 - ADSB in baud 115200
  • serial 3 - grt safefly/spc
  • serial spc 1 - grt safefly tmap communications
  • serial spc 2 - magnatometer
  • serial spc 3 - open
 
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