外文翻译--plc技术讨论与未来发展-plc设计(编辑修改稿)

外文翻译--plc技术讨论与未来发展-plc设计(编辑修改稿)内容摘要：

ould electronics, and later by the German pany AEG, then France39。 s Schneider electric, the current owner. A 084 model is now on display at Modicon headquarters in Brian Dover, Massachusetts. It is posed of General Motors is proposed for Modicon, when the unit is after nearly twenty years of uninterrupted service retirement. The end of Modicon using 84 name in its product range, until 984 appeared. The automotive industry is still one of the biggest users of the development. Early programmable controller is designed to replace relay logic system. These panies in the ladder program, schematic diagram of relay logic is very similar. The plan selection of a symbol, in order to reduce the existing technical staff training needs. Other early programmable controller using instruction list program, logic solver based on the stack. Modern PLC can be programmed in a variety of ways, from the ladder logic more traditional programming language, another method such as the basic and C is the country39。 s logic, a highlevel programming language design program based on PLC state transition diagram. Many of the early PLC no programming terminal incidental, logical graphics capability, this 第 4 页 共 5 页 logic is it right? In a series of logical expression some version of Boolean format, similar to the Boolean algebra. As the programming terminal evolution, it is the ladder logic could bee more widespread, because the above reason. The new format, such as the state of the logic and function block (this is similar to the way of description logic is integrated circuit used in digital logic) exist, but they are still not popular ladder logic. This is mainly due to the programmable controller to solve in predictable and repetitive sequence logic ladder logic, and allows the programmer (writing logic) to see and logic time sequence is easier to any other format possible. The early PLC, to 80 time metaphase, using a proprietary programming team or special programming terminal program, often have logic elements dedicated function keys represent different PLC program. The program is stored in a cassette tape box. Printing devices used to very small due to the lack of memory capacity. Used nonvolatile magic core memory of the oldest programmable controller. Recently, PLC application software on personal puter. The puter is connected to the PLC through the Ether, RS232, RS485 or RS422 cable. Programming software allows the ladder logic input edit. In general, software。