Programmable controller is a member of computer family, which is designed and manufactured for industrial control applications. The early programmable controller is called programmable logic controller, or PLC for short. It is mainly used to replace relay to realize logic control. With the development of technology, the function of this device has greatly exceeded the scope of logical control, so today this device is called programmable controller, or PC for short. But in order to avoid confusion with the abbreviation of personal computer, programmable controller is called PLC for short.
The definition of invention in the second paragraph of Article 2 of China's Patent Law is: "Invention refers to a new technical scheme proposed for a product, method or its improvement." The so-called products in invention patents refer to all kinds of new products that can be manufactured in industry, including solids, liquids and gases with certain shapes and structures. The so-called method refers to the method of processing raw materials and making various products.
Invention refers to a new technical scheme for a product, method or its improvement, which mainly embodies novelty, creativity and practicality. Patent inventions are divided into product inventions (such as machines, instruments and equipment, appliances) and method inventions (manufacturing methods).