The XbusTCO board

The XbusTCO board can control up to 105 turnouts (or other accessories)! If the needs are even greater, a second board, with a different Xpressnet address, configurable by dipswitch, almost doubles this number. In other words, unless your name is Miniatur Wunderland Hamburg, you have a lot to look forward to! As I mentioned earlier, this board comes from Paco Cañada’s website, which was inspired itself by a realization of the MERG (Model Electronic Railway Group).

I could not help but modify this board (not the diagram, only the printed circuit), for the purpose of simplifying it: no RJ11 plug on the board, fewer straps, all the components (diodes, resistors, straps) to be bent at the same length (useful if you have this clever bending gauge), and connectors to let reprogram the PIC microcontroller in situ, ie without being obliged to extract it from its support. But I did not need this, the board having worked fine the first time!

The PCB

The original PCB is available at Paco’s website. Mine is available here (800 KB). There is no change of components, except the absence of an RJ11 plug.

Programming

The .HEX file containing the required compiled program is located here, in a zipped file. Obviously, to program the PIC, you need a programmer, and one that can connect to USB port, because serial ports are becoming more and more rare on PCs.

In my case, I found this one, quite cheap, on Ebay. For less than 40 €, it offers zero insertion force support (more expensive, but much more convenient than multiple tulip supports!), a cable for in situ programming, and a USB cable. And, of course, the driving software.

PIC programmer

The produced board

XbusTCO board

The XpressNet terminals (1) are connected to an RJ11 jack (2) retrieved from a phone plug adapter. Besides, these terminals are not really useful; I could have soldered the wires directly on the board. The cable (3) connected to the RJ11 is a phone cable, cut in half, and connected to the screw terminals LMAB of the command station. This cable is very useful as it also allows me to connect the Lenz LiUSB interface, to drive the layout from a computer.

The board inputs (4) are connected to the Zelio outputs (5). If you swotted up the original diagram, you surely noticed that it is necessary to insert diodes in series with the switches. I could do without it because I only use the first seven addresses.

Wiring diodes “in the air” is neither very aesthetic nor very safe, so I studied a small board that allows to extend the number of switches in groups of seven (three groups in the picture, with two “daughter” boards overlapped and the “mother” board disconnected on left). Overlapping saves terminals, and therefore wiring, thanks to direct inter-board connectors. See the PDF file.

Diode board

It wasn’t necessary to edit the Zelio program, except that I had to swap the outputs to get a geographical proximity between the servos connected to the same decoder.

Bending gauge
1,00 € — price 2014
Micromodele ref. DO-AB5
Gabarit de pliage

PIC Programmer
$35 + $14 shipping — price 2014
Kee Electronics USB Pic Programmer