SoundTraxx LC Series Owners Manual - Manual (Page 29)

LC SERIES DIGITAL SOUND DECODER OWNER’S MANUAL 29
CV 122, Exhaust Chuff Volume
CV 122 can be set to any value between 0 and 255, with the minimum volume being 0 (sound is
off) and the maximum is 255. The default is 128 or 50% volume.
Hints for Setting Engine Exhaust Chuff Rate
Because most locomotives do not respond linearly (i.e., straight line) to the throttle settings, it
can sometimes be difficult finding the magic auto-exhaust chuff rate setting that works across
the locomotive’s full speed range. We have two procedures for setting the chuff rate that have
worked well. The first method is easy to implement and produces good results that should satisfy
all but the stodgiest of nitpickers. The second method takes more effort but produces more ac-
curate results.
Method 1
Begin by setting the starting voltage (CV 2) such that the engine begins to barely move at speed step
1. Then increase the throttle setting until the engine is moving at 10-15 scale MPH. Then adjust CV
116 up or down until the chuff rate corresponds to approximately four chuffs per wheel revolution.
Method 2
This procedure uses the loadable speed curve to compensate for the locomotive’s non-lineari-
ties. Begin by setting CV 25 = 16, CV 29 = 18 (50 if you are using a long address- see Table A)
and CV 116 to the value calculated from the formula above. Set your command station to use 28
speed step mode. Set the throttle to speed step 1 and adjust the first entry in the speed table,
CV 67 until the locomotive speed matches the chuff rate. Increase the throttle to speed step 2
and adjust the second entry in the speed table, CV 68 until the locomotive speed once again
matches the chuff rate. Repeat this process until you have adjusted the locomotive speed across
all 28 speed steps using CVs 67-94.
Diesel Exhaust Settings
The DSD-LC provides two CVs for setting the Diesel Exhaust sound effect:
CV116, Engine Exhaust Control
CV 116 is used to select between manual or automatic engine notching and in the case of the
latter, the number of speed steps needed to advance the engine rpm notches.
Manual Notching
Manual notching allows the engineer to use the function keys to step the engine rpms up or
down independent of the locomotive speed and is more prototypical than automatic notching.
With manual notching you can for example, simulate the sound of a train crawling up a hill with
diesels running at full power!
Manual notching is selected by setting CV 116 to 0. Additionally, you will have to remap two
function keys to the RPM(+) and RPM(-) functions (see
Function Mapping, page 24). We sug-
gest using the F5 key for RPM(+) and the F6 key for RPM(-) which is accomplished by program-
ming CV 39 to 32 and CV 40 to 64. Of course, you can use other function keys as your needs
dictate as well.
Manual Notching with Interlock
This mode interlocks the engine rpms and the throttle setting such that
· Locomotive cannot be moved unless the diesel engine has been started.
· Engine cannot be shut off unless locomotive speed is zero.
Besides the fun of forcing the engineer to follow an operating protocol, this mode is also useful in
preventing inadvertent engine shutoff while the engine is moving. Interlocked Manual notching is
selected by setting CV 116 to 16.
Automatic Notching
When automatic notching is enabled, the engine will startup when the throttle is first increased.