Ladder logic

Ladder logic was originally a written method to document the design and construction of relay racks as used in manufacturing and process control. Each device in the relay rack would be represented by a symbol on the ladder diagram with connections between those devices shown. In addition, other items external to the relay rack such as pumps, heaters, and so forth would also be shown on the ladder diagram. See relay logic.

Ladder logic has evolved into a programming language that represents a program by a graphical diagram based on the circuit diagrams of relay logic hardware. Ladder logic is used to develop software for programmable logic controllers (PLCs) used in industrial control applications. The name is based on the observation that programs in this language resemble ladders, with two vertical rails and a series of horizontal rungs between them. While ladder diagrams were once the only available notation for recording programmable controller programs, today other forms are standardized in IEC 61131-3 ( For example, as an alternative to the graphical ladder logic form, there is also a more assembly language like format called Instruction list within the IEC 61131-3 standard. ).

Ladder Logic

Ladder Logic was the game for the 1998 FIRST Robotics Competition.

Field

The playing field is a carpeted, hexagon-shaped area with an 8 ft (2 m) tall central goal. Three horizontal rail goals extend outward from the center. Each ball placed on the rail goals scores points and each ball in the center doubles the team's score. Around the perimeter of the field are three stations for human players, who work with remote controlled robots on the field to score points. At the start of each match, each team has 3 colored ball at their player station and three balls on the field, and three balls on the rails.

Robots

Each robot can weigh up to 130 lb (59 kg), and must start each match small enough to fit inside a 30" x 36" x 48" space. The robots are powered by two Skil 12 volt rechargeable batteries and use motors from Skil, Delco, and Delphi Interior and Lighting, speed controllers from Tekin, pumps from McCord Winn Textron, air cylinders and valves from Numatics, Inc., and a programmable control system supplied by FIRST. Drivers use joysticks from CH Products and switches from Honeywell to remotely control the robots via a radio link which uses RNet wireless modems from Motorola.