September issue of MR, CV29, and changing a loco's address

[richhotrain]

rrinker

 This calculator makes it easy: http://www.2mm.org.uk/articles/cv29%20calculator.htm

This calculator is the same one that I use.  It is very helpful because it lets you input sample values in order to visualize the CV29 value.

Rich

[rrinker]

 This calculator makes it easy: http://www.2mm.org.uk/articles/cv29%20calculator.htm

So does JMRI.

All current DCC systems keep CV29 calculations hidden, at least for address changes. Enabling speed tables, or changing the NDOTm well, there's the calculator and JMRI for that.

                          --Randy

[jalajoie]

That little look up table will tell you all there is to know about CV29. It is easy fast and without any mystery.

http://www.tonystrains.com/technews/cv29-lookup.htm

 

[JoeinPA]

Richard,

I hope that I am now in compatibility mode.  I agree that the MR article is very helpful and it also points out the value of JMRI for me.

Joe

[narrow gauge nuclear]

There is a great "DCC corner" article dealing strictly with CV 29 in the September 2012 MR magazine. pp,58-59

I have seen numerous past questions pop up here related to changing the address of a decoder and the confusion around it.  It could be as simple as changing a two digit number in CV 1  (classic).  It might, however, be as complicated as having to change from primary to extended  4 digit address involving even more CVs than just  CV 29. 

CV29 controls a lot of this action via bit 5, but before the rank amateur DCC buff starts poking around to change CV 29 to go from primary recognition to extended recognition, they need to know about all the other bits in CV 29 so that they can calculate the proper value to punch in.  This article is really helpful.

Manuals with a few decoders are less than clear as you are jumping about the various interacting CV values controled by CV29.  The older DCC folks and computer gurus have little trouble here now, but newbies who are not "bit" wise are often like babes in the woods.  CV 29 controls and activates a lot of other CV's.  Screwing with CV 29 without backgrounding can send a weak kneed newbie out of model railroading or an old fart back to DC analog.

I'm in the old fart catagory, but was part of the computer revolution in the early 70's when everyone "bit banged" in assembler code and had little trouble entering DCC.

I highly recommend this well done article.

Richard