3rd pair of Circuitron opto-sensors...?

Model Railroader Layouts and layout building
1

Hi

I want to use a 3rd pair of opto-sensors with a some of my of BD-1s. I know they should be wired in series, but want to confoirm that means that one sensor of the pair is wired between SRa and SRb and the other goes between SSa and SSb.

Is this correct?

thanks

craig

2

Circutron has a book “Circutron Electronics for Model Railroads” that gives alternatives on wiring their products, maybe that will have the answer.