What are the performance indicators of PLC?

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1． Storage capacity Storage capacity refers to the capacity of user program memory. The user program memory has a large capacity and complex programs can be programmed. Generally speaking, the user memory capacity of a small PLC is several thousand words, while the user memory capacity of a mainframe is tens of thousands of words. 2． Number of I/O points The number of input/output (I/O) points is the sum of input signals and output signals that the PLC can accept, and is an important indicator of PLC performance. The more I/O points, the more external input devices and output devices that can be connected, and the larger the control scale. 3． Scanning speed Scanning speed refers to the speed at which the PLC executes user programs and is an important indicator of PLC performance. Scanning speed is generally measured by the time required to scan 1K words of user program, usually in ms/K words. PLC user manuals generally give the time it takes to execute each instruction. The speed of scanning can be measured by comparing the time it takes for various PLCs to perform the same operation. 4． Function and quantity of instructions The strength and quantity of instruction functions are also important indicators for measuring PLC performance. The stronger the function and the greater the number of programming instructions, the stronger the processing and control capabilities of the PLC, the simpler and more convenient user programming will be, and the easier it will be to complete complex control tasks. 5. Types and Quantities of Internal Components When compiling PLC programs, a large number of internal components are needed to store information such as variables, intermediate results, retained data, timing counts, module settings, and various flag bits. The greater the types and quantity of these components, the stronger the PLC's ability to store and process various information. 6． Special Function Units The number of types of special function units and the strength of their functions is an important indicator for measuring PLC products. In recent years, various PLC manufacturers have attached great importance to the development of special function units. The types of special function units are increasing day by day, and their functions are getting stronger and stronger, which makes the control functions of PLC increasingly expanded. 7. Scalability The scalability of PLC includes the expansion of I/O points, expansion of storage capacity, expansion of networking functions, expansion of various functional modules, etc. When selecting a PLC, it is often necessary to consider the scalability of the PLC.