Gert van Loo wrote:I understand the problem and the solution.
What you say is that it first needs to switch the power ON and later it has to reverse it.
The article I found had a number of track situations which need the circuit.
On the board I have a CPU, 4 H-bridges and a A/D converter. So I could build a program option for that.
But it is not a trivial program to write. (What if the operator reverses the train???)
1/ I have no DCC rail track. I did the development on a track which was lend to my by Hornby. (Again: Thank you Hornby!).
2/ I think the system gets very complicated.
3/ I am short of time at the moment.
4/ The short circuit protection of the Gertbot is extreemly fast.
Gert, if you find time I'm willing to help out with this and I do have model trains, both DCC and DC but no auto reverse unit.
An auto-reverser doesn't switch power on or of. It takes power from the DCC bus (or main track) and connects it to the loop. Then switching the connection from straight through to cross over, or back when a short is detected. As I understand it, but bear in mind that I don't use them, an auto reverser can be thought of as a very fast automatic change over relay.
For this to work the track section controlled by the reverser must be electrically isolated from the rest of the line.
On DCC the polarity/phase of the signal doesn't matter to the train. The decoder chip inside it handles signal processing, conversion from AC to DC and motor control.
Reverse loops on DC are a whole different kettle of fish though.