Block Occupancy Detection

A key part of the infrastructure on the planned railway is 'block occupancy detection' - a set of circuitry that allows you to know if part of the track is occupied.

For this I am using the BDL 168 from Digitrax. It is suitable for the other loconet devices that I am running For example it tells the DTM30 that a section of track is occupied via loconet avoiding lots of long wires for LED displays, it also interacts with SIGM20 signal controller to automatically control signals, and finally it provides vital information to the computer to allow it to automagically run trains, and hopefully avoid crashes.

It took me sometime to understand the wiring diagrams, they are highly ambiguous - but for my simple test setup you just connect Zone Common wire to the main Rail A feed. then for the section to be detected remove the Rail A wire from wherever it was previously connected and join to any of the 16 detection section pins on the DBL connector. And that is it.

Learning points - I will need to plan lots of rail gaps and feeds into the layout before construction to allow sectioning.

Here is the board and connector mounted on a scrap piece of hardboard :-

And here is it working for the first time, the top LED indicates that the class 25 at the back of the shot is 'in section'.

And finally here is the full array of electronics I am currently using -

From the left we have a Team Digital SMD 82 static controller that is operating the one point motor, then the Digitrax controller and PSU and then comes the box containing the CML DTM 30 and finally the DBDL168. I still have to add a SIGM20 and replace the SMD82 with a CML DAC 10.