Is there some manual or book that de-mystifies setting CV's in DCC? I have purchased three different books on DCC and each tell about CV's but do not deal much with how to adjust them. The instructions with the Walthers H-10-44 are helpful for it and the instructions with the MRC Prodigy are helpful in a limited way. Can anyone direct me to a source for understanding about setting CV's?
TRNJ
Configuration Variables(CV's) are not all standard. Certain ones like the address/manufacturer/model and the most of the speed ones are pretty standard. Sound ones are in the 'user' area and vary from manufacturer to manufacturer.
Programming them with a throttle can be tiring, and having a notepad available is helpfull. I have an old computer attached to my DCC system and use 'Decoder Pro' to program everything - it is much easier. With your MRC system, there is not a computer interface available at this time. And when it does become available, it will need to use the MRC software product.
I keep all of the documentation for each decoder, and download any documentation that may be available form the manufacturer. I print this stuff out, 3 hole' punch it, and file it in my 'DCC Book'. Some decoders(like MRC) do not supoport CV 'read back' and can be a real pain to program as you can not find out what value is currently stored in a CV. That is why I do a 'Reset' on a decoder and then build the entire configuration on Decoder Pro, then download it into the decoder. Without an computer interface, you can still use Decoder Pro to 'build' the configuration and then program it into the decoder with your throttle,
Jim Bernier
Modeling BNSF and Milwaukee Road in SW Wisconsin
This is the NMRA Standard for CV usage:
http://www.nmra.org/standards/DCC/standards_rps/RP-922%202006%20July%2025.pdf
It's 12 pages in PDF format. Print it out and keep it as a reference.
For questions, though, this forum is probably the best place to get answers. Documents are limited in scope, but the people here can respond directly. Once you've gotten into this, it's really much easier than it sounds looking in for the first time.
It takes an iron man to play with a toy iron horse.
Your decoders vary, so you will have to read each accompanying manual to find what changes to what CV's will make the decoder do what you want it to do.
As for actually changing the values assigned to a given CV, which is what I think you have asked, your DCC operating system will also have a manual that will explain in detail how to acquire the decoder on your throttle or base station, how to enter an appropriate programming mode for the action you are contemplating (there are at least four programming modes!), and thence how to acquire the CV(s) you need to modify and assign new inputs, or values, to those CVs.
Generally, you dial in the locomotive/decoder on your hand-held throttle, perhaps on your base station, press "program", and then set the type of programming, that is, the mode....Paged, Ops, etc. Then you probably dial in the CV you want to change, say CV 2 for V-Start (start voltage to get the loco moving just a wee bit), or you enter the CV number on the touch pad. After that, you must enter the new value you wish to assign to that CV. For CV2, the QSI's generally come with a value of 35-37 pre-set at the factory. Maybe your new and tight engine would behave better with a setting of 42, so you try it and see if dialing speed step 1 on your throttle finally gets it to begin creeping along. You enter 42, exit programming, and dial in the first speed step....does it move? No. Re-enter programming, select the right mode (on the DT 400 from Digitrax, the trottle remembers your last programming session's mode and will select it for you), dial in CV2, try 46 this time, exit, and dial in speed step 1. Now it begins to creep along. Maybe 44 would have sufficed. Try it, the same way.
That is all there is to programming CV's.* It sounds horribly involved for those not familiar with it, but just as you can operate a computer without thinking about it these days, programming CV's becomes a drill easily achieved within four or five practise sessions.
*The QSI decoders nest individual sound characteristics in an index of CV's accessed first by the master CV 49. You have to tell CV 49 which sound you want, and the decoder manual will have a table listing the secondary CV under CV50 that will control the sound you want to change. So, it is a two-CV setting for sound and chuff rates on the QSI's, although the Revolutions just out for sale may be different.