Step 7 Lite is an IDE (integrated development environment) for use by automation specialists to engineer and program solutions to automation problems. Some basic aspects of the processes by which automation systems are programmed need to be grasped in order to understand the design of the Step 7 Lite system and the significance of its performance-centered features. They offer the following brief background to set the stage.
Most equipment of modern automation is controlled by software running on specialized computers called PLCs (Programmable Logic Controllers). The systems controlled by PLCs vary tremendously, with applications in chemical process control, manufacturing, machining, power distribution, transit, and many other fields. Automation applications can range in complexity from a motorized window shades and simple panel to operate the lights in a conference room to a completely automated brewery in which the machinery for everything—from mixing ingredients and dispensing to controlling the brewing process and even filling and sealing of bottles is under programmed control.
Companies such as Siemens AG produce lines of modular computer components that can be combined and configured in many different ways to monitor and operate various equipment to support such highly varied needs. In a representative system, a Central Processor Unit (CPU) is combined with a number of input/output (I/O) modules that connect with actuators and sensors in the automation equipment itself. The programs that run on the PLC are planned, written, and debugged by automation programmers using running development software on conventional laptop computers or desktop or workstations. The programs produced by the development software must be downloaded to the PLC itself to operate the equipment.
Automation programming is an exacting profession engineering requiring great attention to detail, mastery of specialized concepts and terminology, and systematic discipline to avoid or eliminate errors. The associated risks with undiscovered errors in PLC code can be enormous. A bug lurking in a PLC program could destroy an expensive piece of material being machined, require the repair of costly equipment, or even lead to injury of personnel.