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Old 04-22-2021, 10:10 AM   #8 (permalink)
brianbremer
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Join Date: Sep 2010
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Per the issue initially reported within this thread, I was able to reproduce and capture the issue of the throttle going low based on physically disconnecting and re-connecting the srxl2 remote during operation.

The low throttle commands did not occur on every disconnect/connect cycle and I was unable to reproduce the issue based on a fade or hold condition. Based on my testing the throttle low commands only occurred during the cold start (power on initialization) of the srxl2 remote receiver.

I provided the information that I had found (sans the cold start determination) to the remote firmware developer and he was able to identify the issue leading to the intermittent low throttle commands I was running into. I am currently bench testing updated firmware now that address this specific issue.

I confirmed with the developer that this could only occur during a cold start which matched my earlier testing determination.

For the specific issue mentioned here in this thread to occur in flight you would have to experience a power system brown out or a remote power brownout (aka damaged cable).

Although the disconnect/re-connect bench test mentioned here produced similar results (throttle cut) to what occurred in the other thread it does not necessarily mean this test "duplicates" what occurred in flight on the other models being discussed unless that model experienced a brown out due to the power system or a damaged remote cable.

There is a lot going on in the other thread referenced in the original post here. There is one case mentioned where the fbl controller reported a "coldstart" per the log in flight, it is possible the coldstart could of been due to a power system brown out and in that case the issue might be related to the issue mentioned here but it would depend on how that fbl controller handles a coldstart during operation issue.

I also do not know the internals of how msh handles the srxl2 remotes failsafe packets or the handling of the failsafe determination within the fbl unit itself.

In the case of the fc6250hx open stock since it is using a mix of older remotes and srxl2 remotes the fc6250hx is handling the failsafe determination and failsafe throttle position. If no remote packets are received for a period of 2 seconds failsafe is activated and the throttle is driven to the Fwdprg->Setup->Throttle->Failsafe position and all other inputs hold the last position. Once a single remote packet arrives the failsafe is deactivated.

Per the fc6250hx if a power system brownout should occur the fc6250hx will cold start and is fully initialized and up and running in under 1/2 of a second under all conditions. Once remote packet data is received the throttle is driven to the received value.

Per the remote updated firmware mentioned above, I will continue bench testing and regression testing in work models however I will not be updating remotes in my personal model until the regression testing has been completed.

For those that disagree with my decision to continue flying the prior firmware keep in mind in the case of the fc6250hx you can operate the system using the older dsmx remotes, the srxl2 remote is only needed for telemetry and forward programming.

Keep in mind for the specific issue mentioned here in this thread to occur in flight you would have to experience a power system brown out or a remote power brownout (aka damaged cable), in addition to those conditions, the issue does not occur every time.
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My Projects: 150 S, 200 SRX, 200 S, 230 S v1/v2, 270 CFX, Fu270, Fu480: AR636/AR6335 Heli, FC6250HX, AR6250MHX

Last edited by brianbremer; 04-22-2021 at 12:31 PM..
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