What are decoders

The basics of decoder programming

In this article we would like to introduce you to the basic aspects of decoder programming. We will briefly show how settings are made on the decoder and how programming can be carried out. Then we will show you the most important CVs and what effects the settings have on your locomotive. At the end of this article there is a preview of future articles on the topic of decoder programming.

If you deal with the topic of decoder programming, you will quickly come across the term CV stumble. The term is hidden behind the abbreviation Configuration variable. In these variables, data is stored that is used to make settings on the decoder. The term CV is the most important term in decoder programming.

So-called Bits written with information. 1 bit is the smallest unit and can only have the states 0 and 1. A byte again consists of 8 bits and results in a CV. This gives the value range for a CV from 0-255. Depending on the decoder, you can access several hundred CVs and thus influence the behavior of the decoder and thus the locomotive.

The CVs of a decoder can be checked with the help of a Digital center or a programming device. Even if the surfaces of the control panels look different, the technology in the background is always the same. Detailed information on programming decoders can also be found in the instructions for your central unit.

Decoder manufacturer

The large decoder manufacturers offer suitable programming devices for their own decoders. The devices are usually connected to a computer via USB. The changes are then made on the computer in software and then uploaded via the programming box. This technology makes it possible to easily make a large number of changes and to record sound decoders with corresponding files. It is even possible to transfer your own sounds to the locomotives.

The available devices are listed below. It should be noted that only the manufacturer's own devices are able to play sound on their own decoders. For example, it is not possible to play a Märklin sound decoder with an ESU LokProgrammer. However, general programming changes at CV level are possible as at any other control center.

Decoder manufacturer

The following table is extremely important for the basics of decoder programming. Even if the programming interface looks different depending on the control center, the Assignment of basic CVs for certain functions the same for every decoder:

CVSurnamedescriptionRange of values
1Locomotive addressDefines the address at which the locomotive can be reached1 – 127
(3 ex works)
2Starting voltageControls the speed in speed step 11 – 255
3Acceleration timeTime that is required to accelerate from the state to VMax0 – 255
4Braking timeTime that is required for VMax to come to a standstill0 – 255
5Top speedSpecifies the maximum speed0 – 255
6Mid-speedControls the speed that the locomotive should run when the controller is only turned halfway.
Here it is advisable to set half of the VMax.
0 – 255
7Version numberDisplays the installed software version
8factory settingsThis CV is especially important if you want to reset the decoder to factory settings.
In this case CV 8 must be set to 8. There are exceptions!

With the mentioned CVs you can make the most important settings on a locomotive decoder. The fear of doing something wrong is in any case unjustified because the factory settings have it restored at any time.

In addition to influencing the driving behavior, modern locomotive decoders also offer extensive control options for the Function outputs. Other functions are, for example, driving in double traction, assigning light functions to function outputs, setting sound volumes, etc. The topics mentioned and other options will be explained in more detail in this blog over time.