SoundTraxx LC Series Owners Manual - Manual (Page 15)

LC SERIES DIGITAL SOUND DECODER OWNER’S MANUAL 15
PROGRAMMING THE CVs
The final installation step (At last!) is programming the DSD-LC’s Configuration Variables or CVs.
What is a CV?
CV stands for Configuration Variable, which is the industry-adopted term for a decoder’s user-
programmable memory locations. CVs allow you to customize individual decoder properties such
as the address, momentum, throttle response, sound volume and much more. Once a CV has
been programmed, the setting will be permanently remembered even after the power has been
turned off. A CV can be modified as often as necessary by simply reprogramming it with a new
value.
With the large number of CVs available, first inspection of the available options may cause
confusion and perhaps a bit of a brain-cramp! Take an aspirin and relax.
As you have already seen the DSD-LC has been shipped with all CVs pre-
programmed so you can begin using your locomotive immediately without having
to worry about what adjustments to make.
The following paragraphs break the DSD-LC CVs into various subsystems so it is only necessary
to change a few CV’s at a time. As you become comfortable with the DSD-LC’s operation,
move onto a new section and begin exploring the options and capabilities found there. For
more technically inclined users, detailed information on any CV can be found in the LC Series
Decoder Technical Reference available from your dealer or SoundTraxx for a small charge or
from our website for free.
Bits and Bytes
One of the most confusing aspects of programming a CV is figuring out what all the different bits,
bytes and x’s found on the various decoder manuals (including this one) mean. The problem is
compounded further by differences in each command station manufacturer’s user interface. For
those users unfamiliar with such terms, a short math lesson (ugh!) is in order before proceeding:
Each decoder CV stores a numeric value that can be represented in one of three forms:
Decimal - This is the form everyone is familiar with and we use in our day-to-day
lives. Numbers are represented as a sequence of digits composed of the numerals
0,1,2,3,4,5,6,7,8, and 9.
Hexadecimal - Also referred to as simply “hex”, this is a more specialized number
representation that, in addition to 0 through 9, also uses the characters A-F. It has the
advantage that a given decimal number can be more compactly represented. For example,
the decimal number 127 converts to a simple 7F in hex (one less digit). This allows user
interfaces with a limited number of digits (i.e., the LCD on your cab) to display a wider range
of numbers.
Binary - Binary numbers get their name from the fact they use only two digits 0 and 1
called ‘bits’ and is the fundamental number system used by all computers including the
ones found inside a digital decoder. Because there are only two bit values, it takes more
digits to represent a number using binary. The decimal number 127, for example, is written
as 01111111 in binary notation. A ‘byte’ is a binary number made up of eight bits. And a
‘nibble’ is half a byte or four bits. Really! We didn’t make that up.
Coincidentally, each CV is made up from one byte or eight bits and can store any number
between 0 and 255. Most of the CVs contain a single piece of data that can be easily
represented in any of the three forms. i.e., CV 3, the acceleration rate, can be loaded with any
value from 0 to 255 and it always affects the same thing - the acceleration rate.