Step 2: Configuring the Decoder
The next CV you will want to change is CV 29, Decoder Configuration Byte. CV 29 is one of those complicated bit variables mentioned earlier and is used in conjunction with other CVs to set a multitude of decoder characteristics including Locomotive Direction, Speed Step Mode Selection, Speed Table Enable and Alternate Power Mode Enable.
Locomotive Direction - Causes the decoder to invert direction commands so that the locomotive runs in reverse when it receives a command to move forward and vice-versa. This operating mode is most useful for setting up diesel engines that ran with the long hood section forward. However, it is also useful for electronically correcting installations where the motor wires were accidentally reversed and avoids tearing apart the locomotive a second time.
Speed Step Mode Selection - As it is a digital system, Tsunami splits the throttle voltage over its minimum and maximum range into discrete speed steps. Tsunami can be configured so there are 14, 28 or 128 individual speed steps. The largest number of steps will give the smoothest throttle response. Since not all DCC systems have the ability to control 28 or 128 speed steps, your choice will depend upon the technical capabilities of your command station.
Speed Table - Sets the decoder to use the speed table specified by CV 25 (see “Configuring the Throttle”, page 17).
Primary or Extended Address - Sets the decoder to recognize its primary address in CV 1 or extended address in CV 17:18 (see “Configuring the Address”, page 13).
Alternate (Analog) Power Mode - Enables the decoder to work with an alternate power mode (such as DC operation) as set by CV 12 when a DCC signal is not present.
To assist the novice user, we have created Table A on the next page that lists the correct value for CV 29 to get the desired operating modes.
To use the table, simply find the row that has the modes you want and program CV 29 with the listed value.
The advanced user should refer to the Technical Reference for more details. Remember, table values are in decimal. If your command station uses Hex (Hexadecimal), you will need to convert the value shown using Appendix A.
Tsunami Steam Sound User’s Guide