Page 4 H0 Sound Decoder MX640
3.
Addressing and Programming – CV table
Every loco decoder requires a separate unique address with which the loco is controlled using a
cab.
All NMRA-DCC compliant decoders have 3 as their factory default address
(NMRA stan-
dardized decoder address at delivery).
DECODER INSTALLATION:
After installing the new decoder in a locomotive (see chapter “Installation and wiring”), it can be
tested with address #3. As a minimum, either the motor or headlights need to be connected (better
yet both), to enable decoder acknowledgment during programming. Doing a complete installation
before programming the decoder is often more practical.
THE ADDRESSING AND PROGRAMMING PROCEDURE:
The
procedure
for programming and reading of addresses and configuration variables is covered
in detail in the
instruction manual for the cab (MX21, MX31....).
For other systems consult the
appropriate manual.
Programming a decoder with a PC and ADaPT software (by E.Sperrer, software developer) is a
lot easier and more convenient!
Technical note to decoder acknowledgments during programming:
When programming a decoder with a cab or computer, every successful programming step will be made visible by
the decoder. The same acknowledgment method is used when reading the configuration variables.
The acknowledgment is based on short power pulses that the decoder generates by briefly turning the motor and
headlights on, which the command station recognizes at the programming track. It follows that the acknowledg-
ment and read out of a decoder is only successful if the current consumption is high enough, which means that
the motor and headlights have to be connected or at least one of the two.
The decoder won’t use the headlights for acknowledgment if CV #60 is set to a value of 40 or less. This is to prevent dam-
age to bulbs since this setting is often used in conjunction with low voltage bulbs. The motor is then the only load used for
acknowledgments!
The following pages show the tables for configuration variables (CV’s).
Table
of configuration variables
CV’s #1 to #255
followed by (chapter 4, 5):
SUPPLEMENTAL NOTES
(“Add. Notes”) and Function mapping.
followed by (chapter 6):
ZIMO SOUND selection and programming
; description of basic functionality and operat-
ing procedures, and
Table
of configuration variables
CV’s # 256 to #511.
HELPFUL HINTS FOR CV PROGRAMMING:
If you are familiar with CV programming please skip this section and go directly to the CV table below!
CV programming is not the same for all CV’s. While the programming procedure is the same for all
CV’s, the calculation of the individual CV values varies.
For some CV’s it is obvious what the value is supposed to be and can easily be derived from the
“Range” and/or “Description” column in the CV table. This kind of CV acts similar to a volume con-
trol.
For instance, CV#2 determines the minimum speed applied at the cab’s first speed step:
CV
Designation
Range
Default Description
Vstart
1 – 252
(See add.
notes)
2
Entered value = internal speed step assigned to
lowest cab speed step.
Bit 4 in CV # 29 has to be 0; otherwise individual
speed table is active.
The “range” column clearly suggests any value from 1 to 252. The higher the value the faster the
engine runs at speed step 1 and vice versa.
Another similar CV is the “dimming” CV #60:
CV
Designation
Range
Default Description
#60
Reduced function
output voltage
(Dimming)
0 - 255
0
The actual function output voltage can be re-
duced by PWM. Useful to dim headlights, for ex-
ample.
Example values:
# 60 = 0 or 255: full voltage
# 60 = 170: 2/3 of full voltage.
# 60 = 204: 80% of full voltage.
Again, the range column suggests using a value between 1 and 255 and in the “description” column
it is explained that the brightness of the light increases with the value.
Other CV’s are easier to understand if you think of them as a small switch board, where you can
turn individual switches ON or OFF. Such a CV is made up of 8 “individual switches” called Bits and
the group of Bits is known as a Byte (which is the CV itself or the switch board, if you will). The de-
veloper determines how many bits of a CV can be altered. On some CV’s you can change the set-
ting of all 8 Bits (switches) and on others only a select few. The Bits (switches) are numbered from
0 to 7 and each has a specific value (
see the chapter “Converting binary to decimal”
for more
on binary calculations). Each Bit is turned ON by adding its value to the CV and turned OFF by sub-
tracting its value. Add the value of each Bit you want to turn ON and enter the total to the CV.
One such CV is CV #29 (next page):
