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Post by edwardsutorik on Nov 19, 2015 11:30:23 GMT -8
This hasn't happened to me before, but I sure didn't like it:
I had one engine on the layout from previous operation. When last run, I had simply slowed it to a stop and turned the power switch off. All things I've done many times before.
This morning I turned the system on. The loco started at full speed on its own.
Has this happened to you? Do you know why?
I'm leaving out the system name and the loco mfg because I'm casting a wider net, for now.
Ed
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Post by jonklein611 on Nov 19, 2015 11:39:20 GMT -8
I've had this experience with some Digitrax systems. If you dispatched it with it at speed, it'll behave that way when it's re powered. Other gremlins have known to take their toll (Did you feed it after midnight?)
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Post by edwardsutorik on Nov 19, 2015 12:44:09 GMT -8
Other gremlins have known to take their toll (Did you feed it after midnight?) Oh, gosh, no. I know that gremlins suffer from indigestion if they eat late. And then they're all cranky when they wake up. I, for one, don't need that. Must be something else to explain their, uh, depredations. Ed |
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Post by bnsf971 on Nov 19, 2015 16:19:46 GMT -8
Ed, it's doing that because you don't have DC disabled. If you have a 4 digit address, simply set cv 29 to a value of 34. That will turn off DC, and it won't do this again.
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Post by edwardsutorik on Nov 20, 2015 13:44:19 GMT -8
Ed, it's doing that because you don't have DC disabled. If you have a 4 digit address, simply set cv 29 to a value of 34. That will turn off DC, and it won't do this again. Terry, I certainly THOUGHT I had disabled DC. But then, I think a lot of things. Yup, I checked, and CV29 was 38 instead of 34--DC being switched on. I've had some trouble previously with CV's not being what I want. In particular, I would enter that I wanted the "F" end switched, and it just wouldn't happen. DCC is GREAT. Except when it's NOT. Thanks again. And I'll double check my other locos. The ones I "know" are DC disabled. Ed |
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Post by Mark R. on Nov 20, 2015 19:09:10 GMT -8
When a decoder first powers up, it goes through a check-sum sequence. One of those aspects is for the decoder to determine what type of voltage it's seeing on the rails. If it sees no voltage, it prepares itself to be operated by DC. If it sees voltage, it prepares itself to see a digital command. A decoder goes through this sequence (which only takes a fraction of a second) every time there is a power interruption.
If for what-ever reason (it's electronics after-all) it hiccups at this step and thinks it's supposed to be waiting for a DCC signal and sets itself up for DC expectance, it takes off at full "DC voltage" with the DCC voltage present on the rails.
That's why it's a good idea to turn off DC enable so the decoder will never look for a DC aspect when "booting up".
Mark.
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Post by edwardsutorik on Nov 27, 2015 12:52:17 GMT -8
Thought I'd check back here to see if there were further comments. And Mark's "further" is/was quite helpful.
Thanks, Mark
Ed
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