I like many others have been attempting to install a Block Occupation system within my model railway. But as yet I have not been able to form a satisfactory method that does not have one short coming or the other.
I have found that the most satisfactory method is to employ Optocouplers in the feed to track circuit from my (Gaugemaster 100 series) controller. This provides for any interference with the power circuit to be minimal but subject to a power loss of some 1.3 vF consumed by the Opto's. It works fantastically well, but wait for it, there is one downside to it and that is: The Opto's do not commence working until they receive some 1.3v's, which means with the controller turned off there is no output at all from the Block Occupation circuit. I can always leave the controler set at the 10% position but then I can't always hope that I will remember to do so and as for visitors using the system then it is very likely that they would fall if not at the first fence then almost definately at the second fence.
So you guys out there with super intelligent electronics know how do I induce enough power to switch on the optocouplers when the controller (or controllers are) is at "OFF" when the controller leakage current equals just+195mV's.
Controller: Gaugemaster 100 series Controller output: 0.195v to 14.5v-DC. Controller auxiliary output 16v~AC Auxiliary circuit used on the Transistor side of the Optocouplers is +13.75v-DC Optocouplers are: 4N35's Track feed utilised is: controller positive with the optocouplers wired in series with the return wire being the continuation of +v controller back to the
- rail. Twin optocouplers are utilsed to determine the direction of track current.
Any help would very gratefully received.
Cheers, H Chris Spreckley