Electrical systems on a model railroad consist of numerous wires, switches, motors, electronic controls, lamps, and more. But rather than dealing with circuitry at a low level, S³ works with "devices".
A device in S³ is a specific model railroad object, such as a …

Control logic consists of a sequence of one or more “Logic Lines”, each of which contains a set of conditions that affect the state of a device. For example, a logic line may state Signal 3 is Red when Block 1 is Occupied and Turnout 7 is Reversed. Any number of …

When a device has multiple "lines" of logic controlling it, they are processed in sequence from first to last (top of the list to bottom). As soon as a condition is found to be true, the state of the device is set and the remainder of the lines are ignored. In …

To trigger any action on your layout, you generally need various types of inputs. For signal operations, the basic items are a block detector, showing the existence of a train in a specific section of track, a turnout position detector, or a sensor showing that a …

In S³ Logic, any device may be controlled based on the state of any other device. So a signal may be controlled based on the state of some other signal(s). Why would we want to do this?

Take a look at the diagram. Signal 2 will have some fairly complex logic …

Although S³ does not currently support a real-time clock, it does allow the timing of dozens of events simultaneously. Five different types of timers are available, and a timer can be triggered by various devices and events and may be used to control the …

Why analog in a digital system? For some applications, it is necessary to provide adjustable outputs to control the brightness of lamps or the speed of motors.

Analog outputs aren't truly variable voltage, but instead are rapidly pulsed on and off to give the …

The careful observer may have noted that the S³ and I/O boards are built around standard Arduino modules, specifically the Raspberry Pi Pico and Teensy 4.0 processors. These high-performance, low-cost modules offer an incredible value and greatly simplify our …

I frequently get the question "is S³ a DCC system?" The short answer is No, and it's not trying to be. S³ fits into another category that is sometimes referred to as a "Layout Control Buss".  

S³ functions in areas of control other than operating trains, which is …