SoundTraxx Tsunami Steam Users Guide - Manual (Page 49)

Tsunami Steam Sound User’s Guide Page 46
be loaded with any value between 0 and 255. Higher values will yield higher
chuff rates for a given throttle setting. A typical synchronization rate may be
computed as:
SPD
CV Value = 115.9 X ——— X Gear Ratio
DIA
where SPD is the locomotive’s top speed in scale miles-per-hour at full
throttle and DIA is the locomotive’s driver wheel diameter in scale inches,
and Gear Ratio is the gear ratio for shays and other geared engines. For
conventional steam engines, use a Gear Ratio = 1. The driver diameter
can be easily measured with a scale ruler but remember to convert the
measurement to scale inches.
If you don’t know your locomotive’s top speed, you can also estimate it and
still get pretty good results. A good rule of thumb is to use 45 MPH for freight
locomotives and 70 MPH for passenger engines.
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 accurate 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-linearities. 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.
Exhaust and Rod Clank Volume Control
CV 131 controls the exhaust chuff volume while CV 135 controls the side rod
Sound Programming