[Accrs-o] Signaling - Anodes and Cathodes

[ACCRS O Scale list]

The issue of Common Cathode wiring that emerged last night is potentially significant to how we structure the overall installation.  After some research, as far as I can tell, everyone else in the industry (NJI and Details West) manufactures common anode signals. I assume this is to be compatible with the Chubb C/MRI output cards as that is probably at least 50% of total signal output drivers installed. Most other circuits also seem to lean to Common Anode. It sounds like Custom Signals based their whole O scale line on a controller design by Atlas that was a current source and therefore needed common cathode signals. So all of the Custom Signal targets require 3 current sourcing output pins to work as built. None of the available C/MRI output cards do current sourcing as stock. All 10 of our current output cards are wired for current sinking. If we go all current sourcing, signals from other manufacturers will not work. So if we use some Custom Signals and some NJI signals we must have a mix of output types for both. Deciding on this mix and allocation seems to be required.

Anyway, I wrote a long "Current State - what we know", a few questions, and three potential solution options in the signaling topic in groups.io.

I think this just became the critical path for the project as it impacts almost every other design and implementation decision going forward. Our choices of C/MRI, types and C/MRI locations where individual devices are supported are all dependent on these choices.

Phil Edholm
Mobile 408-832-5618

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