Devices in S³

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 signal, turnout, sensor, or indicator light. S³ implements more than a dozen unique devices, with built-in functional support for each of them. 

The user assigns a unique number to each device, between 1 and 255. This means a layout configuration may have up to 255 signals, 255 turnouts, 255 blocks, 255 indicator lights, etc. In 20 years of layout automation, we have yet to approach these limits.

For many devices, there are specific types that may be selected. For example, a signal may be a typical 3 aspect, a 2-position semaphore, or a PRR position light display. Turnouts may be controlled via various types of motors having unique characteristics. Some devices may have few, if any, options.

A device may be set to any of its possible "states", depending on the device type. For example, a 3-light signal may be set to green, yellow, red, dark, or a flashing aspect of any color. The user-defined logic only has to deal with devices and states, while the built-in device drivers control the electronics to achieve the desired result. All the details of the operation are carried out by the S³ controller and I/O boards, and all devices may be operating simultaneously, without any special considerations on the part of the user.