SoundTraxx LC Series Owners Manual - Manual (Page 17)

LC SERIES DIGITAL SOUND DECODER OWNER’S MANUAL 17
Reading CVs
Certain command stations also allow you to read a CV during Service Mode Programming,
which is useful to verify its current setting. If you have trouble reading or verifying CVs, the
problem may be due to the design of your command station and not the DSD-LC itself. The
DSD-LC and all other decoders communicate back to the command station using what’s called
an acknowledgment pulse, which is defined in NMRA RP-9.2.3 as “an increased load on the pro-
gramming track of at least 60mA for at least 5ms.” Like most decoders, the DSD-LC generates
the acknowledgment pulse by momentarily applying power to the motor. You can often visually
verify that the DSD-LC is properly responding to your programmer by observing a slight twitch in
the motor shaft when a read or write command is given.
If your DSD-LC is otherwise working properly (i.e., responds properly on the mainline to speed
and direction commands) but your command station is having troubles reading CV data from the
DSD-LC, it may be due to incompatibilities between the electrical requirements of the DSD-LC
(which are different from conventional decoders due to the added audio circuitry) and the electri-
cal characteristics of your programming track. In such an event, we suggest you simply go ahead
and program the data into the CVs anyway. Usually the DSD-LC will accept the data and function
properly when placed back on the main track. You can also try a different programming mode. If
your system supports it, the best way to program the CVs is Operations Mode, as it allows you to
immediately see or hear the results of your changes.
It is important to realize that not all programming modes will program all CVs. Additionally, the
specific programming mode you use will depend upon the type of DCC system you are using.
Some of the newer DCC systems can automatically select the proper programming mode so all
you need to do is specify the CV number and its new value. On the other hand, some systems
support only a few of the programming modes and may restrict which CVs you can program. If
in doubt, refer to your DCC system’s manual or contact the manufacturer to determine which
methods they support.
Programming Procedure
As each DCC system is different, the procedure for programming a CV will vary depending upon
the system. Unfortunately, we cannot provide detailed instructions to cover every command
station and have to assume that you have some level of understanding regarding it’s capabili-
ties and operating procedures. For specific programming procedures, please consult your DCC
system manual.
Step 1: Configuring the Address
The first group of CVs you will want to change are those that set the DSD-LC’s address:
CV 1, Primary Address
CV 17:18, Extended Address
The DSD-LC may be set up to recognize either the primary address (also called the short ad-
dress), which provides a range of 1 to 127 or the extended (long) address, which has a range
of 1 to 9999! Whether you use the primary or extended address will first depend on whether or
not your DCC system uses extended addressing (not all of them do - if in doubt, see your com-
mand station owner’s manual.) Second, it will depend on your preferences and the numbering
scheme you use for setting your decoder addresses. The extended address has the advantage
that you can use all four digits of a locomotive’s road number for the decoder address making it
easy to remember. Be aware that some DCC systems do not support the full range of available
addresses.
Primary Address
To use the primary address, simply set CV 1 to the desired address between 1 and 127. Note:
The primary address can only be set in service mode.
Extended Address
The extended address is actually made up of two CVs, 17 and 18. Unless you are an experi-
enced user, you should not try to program these CVs individually as a specific protocol is