This article is from before 2012
DCC - 1 - Digital Command Control
I surprised myself in 2004 by changing to digital command control to operate my layout. On eBay I was able to buy an MRC commander 2000 for a nice little price. However, compared to other dcc systems the capabilities with the commander 2000 are limited. But experimenting with this MRC dcc system and two dcc equipped locomotives, changed my mind quickly.
The biggest part of my layout is going to be digital controlled. After research on the internet as to what all the possibilities are and still owning a few old computers, I decided to use a software system that allows a computer to generate the required digital signals. The software I have running is available as a free download, thanks to their designers, on the internet, at the following websites: MRDirect and Koploper. The websites and software are in the Dutch language, but this kind of software should be available in other languages, like English and German. (Note: as of 2025 I have noticed the MRDirect website and software download are offline. I will keep the download available on my website)
My track switches decoders and signals decoders are from the Motorola system and the train decoders are from the DCC format. (MRC and Lenz) Track occupancy works with the S88 system, all self-made except for the DCC locomotive decoders.
I have made a few circuit boards and each one with its own function. I found the schematics in books and on the internet. Some are a combination of circuits and may have small modifications. The signal decoders are modified track switch decoders, and I have the schematic from Mr. A. de Heer. I have also found a lot of information on the website from Mr. R. Evers. I am thankful to these two persons for the help in making these decoders. (Note: as of 2025 I have noticed their websites are offline.)
Digital command control, both Motorola and DCC protocols.
I have painted the circuit boards in various colors for ease of identification. I had plenty of spray cans of paint left over anyway. So are the switch decoders red, high power switch decoders yellow, signal decoders orange, and the S88 feedback circuits blue. And finally, the occupancy detectors are painted green.
The control center
My layout is operated with two computers, and the system is almost like a Intelibox. It handles both the Marklin Motorola format and the NMRA DCC format. These different formats can be interchanged simultaneously.
The first computer controls the decoders, both train and track switch / signals. He is also responsible for the track occupancy. This computer runs MRDirect.
The second computer controls the first computer, allowing for a fully automatic timetable operation as well as manual controlled by mouse and keyboard operation of the layout. This computer runs on Koploper.
It takes a little while to learn to program the software, but after a little while it all works perfect. This test layout is already disassembled and in its place is the staging yard build.
Here the monitor from the first computer with MRDirect software.
Here the monitor from the second computer with Koploper software.
Both computers working together.
I am using an MRC power station to provide the required DCC power to the tracks.
Five brand new transformers, purchased before I converted to digital control, are still being used on the layout.
This is a test layout to get to know the software Koploper. With this layout I also tested the various circuit boards I made, as well as the hard and software on the computer itself.
MRC decoders as used on my layout; I got them cheap from a co-worker.
I also have two Lenz decoders with functions.
The occupancy detection from the TRACK to the PC
Here we take look underneath the staging yard with 10 tracks. The wires hanging down are for the track occupancy, which has to be hooked up still.
The red circuit board is a double track switch decoder which operates the 8 track switches in the staging yard.
The S88 circuits chain linked together. The small circuit at the beginning is the interface. All those circuit boards are used for occupancy detection. At this time, I have a total of 9 circuits with 16 detectors each, so that totals 144 detectors.
The computer is capable of keeping track of 31 S88 circuits totaling 496 detectors! I have plenty space for expansion, but at this time I am not in the mood to solder another circuit board.
Ready to be put in service: six freshly soldered S88 circuit board
The result of a few months soldering circuit boards in the evening.
Testing the circuit boards before I insert the IC’s. Only one from the six circuit boards had a minor error.
Once they pass the test the IC’s get inserted.
Once connected to the computer, the inputs can be checked for functionality.
The interface which connects all the S88 circuit boards to the printer port of the computer.
The monitor of the first computer, with MRdirect software. The S88 test screen is used to test the circuit boards.
The occupancy detection signal from the TRAIN to the PC
A section of track with detection. A car with a build in resistor over the wheels will cause a flow of current to pass through the opto-coupler from the detector.
Each cable is numbered with a unique number, which is followed throughout the layout and into the computer’s software.
The current from the sections of track which are occupied, enter the occupation detectors. The signal is now continuing to the corresponding S88 circuit board.
Diodes are in place to provide a voltage drop on the tracks which are not connected to a detector, to keep the digital signal going on the entire layout.
The signal from the occupancy detectors enters the S88 and via the interface head over to the computer.
Finally, the signal “track is occupied” enters the computer. The 5-volt needed to power the S88 circuit boards, is coming from the computer. (red connector)