IS200SCTLG1A
IS200SCTLG1A
IS200SCTLG1AE
lectrotechnical Commission (IEC) issued the first draft of the PLC standard in November 1982, the second in January 1985, and the third in February 1987. The definition of a programmable controller in the draft reads: “A programmable controller is an electronic system for numerical arithmetic operations, designed for applications in industrial environments. It uses programmable memory to store user-oriented 
instructions such as logical operations, sequential control, timing, counting and arithmetic operations, and controls various types of machinery or production processes through digital or analog input/output. The programmable controller and its related peripherals are designed in accordance with the principle of
easy integration of industrial systems and easy expansion of their functions. This definition emphasizes that a programmable controller is an “electronic system for the operation of numerical arithmetic”, that is, it is also a computer. It is a computer “designed for use in industrial environments”. This industrial computer uses “user-oriented instructions” and is therefore easy to program. It can complete logical operations, sequential control, timing, counting and arithmetic operations, it also has the ability of “digital or analog input/output control”, and is very easy to “industrial control systems into one”, easy to “expand”. The definition also emphasizes
