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Electric Stunt => Gettin all AMP'ed up! => Topic started by: FLOYD CARTER on May 22, 2016, 12:49:09 PM
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I had been flying with my KR type 2 timer. All working well. The plane then sat in storage for many months (no battery installed).
Tried to fly it yesterday, and discovered the timer had changed settings. Start delay had gone from 25 sec to 1 sec. Flight time went down to less than 1 minute.
After eliminating the other components, I re-programmed the timer according to instructions.
Now it works again.
I'm pretty careful, and I don't think I ever plugged in the battery jumper with switch ON.
Is it possible for the timer to "forget" after a while?
Floyd
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I've not seen that problem with KR and used for about 1000 flights. As you suggested, problems can occur if you leave the switch on and power up, or if you put the programmer on backward/upside down. It doesn't sound like you did that as you were not programming at the time.
PM to Eric or Keith might be helpful.
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So over the winter the memory cleared?
Phil
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Floyd:
Basic KR program is installed as firmware. The default settings are 20 seconds start delay, 5 minute flight time, 9000 rpm and variable gain of 1. Hooking up the battery with an open switch would have sent the program back to the defaults.
I can not imagine what kind of situation would cause the settings to change to what you experienced. The fact that you were able to reprogram your original settings indicates that the firmware was not damaged in any way (had it been damaged you would not have been able to change the settings at all). This would eliminate the program stick or the ESC throttle lead being installed upside down as that would have wiped the firmware completely and you could not have reset anything at all.
This is a complete mystery to me. Perhaps Keith can shed some light on what happened. Drop him a line (he is in Australia right now but has his laptop with him).
Regards
Eric Rule
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I can not imagine what kind of situation would cause the settings to change to what you experienced.
I have been a circuit designer and an embedded software engineer for over 25 years now, and I can assure you that having situations happen that no one can explain is, if not routine, then at least a frequent enough occurrence that there is a highly technical term for the phenomenon. This name is:
Weird Chit
And I think it has happened in this case (Floyd used to work for Cray -- he should know all about this).
(Incidentally, this is why Brett Buck got the rule passed about restraining electrics any time the battery is plugged in, and why I was doing my best to stand right behind him nodding my head "yes". You can design electronics and software in a way that minimizes the weird chit even to levels low enough that people feel confident running airplane primary flight control surfaces with 'em -- but doing so drives up the cost of development, and the less weird chit you allow, the more it costs.)
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Not Cray. Make that Amdahl Computer. (so-called "super computers"). I designed the power supplies and power distribution system, along with overall cooling requirements. My other task was Manager of the Technical Development Laboratory.
Floyd
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Hi Floyd,
Eric has answered well and in this case it sure does not make sense, so I'll revert to the Tim Wescott presumption y1 These things can and do happen but fortunately not too often.
Keith R