LOGO! series products are an innovative universal logic control module developed by Siemens in 1996. It fills the technical gap between traditional relays and PLCs, and has now developed into a modular standard component products. The module itself integrates 8 basic functions such as "AND", "OR" and "NOT" as well as 28 proprietary functions such as time timing, counter and analog processing. LOGO! replaces traditional functions by using internal function block programming. The external wiring scheme of the relay switch is in a small module. Users can arbitrarily call the various function blocks needed to edit their own applications, thereby realizing the combination of many timers, relays, clocks and contactors. control tasks can be achieved.
Precisely because LOGO! covers some functions of traditional relays, to a certain extent, users can understand LOGO! products as "intelligent relays". Since the module itself has a variety of timer and counter function blocks, it can save a variety of low-voltage electrical components in the control cabinet of system equipment. At the same time, since the relay output point of the LOGO! control module has a maximum current carrying capacity of 10A, it can also be directly connected to various actuators, such as small motors, lighting equipment, etc. Compared with traditional relay solutions, LOGO!'s solution has the advantages of reducing connection wiring, shortening equipment wiring time, saving control cabinet space, and facilitating maintenance.
For PLC, take Siemens’ S7-200 as an example.
The S7-200 series is a programmable logic controller (MicroPLC). It can control various equipment to meet automation control needs. The user program of S7-200 includes instructions such as bit logic, counters, complex data operations, and communication with other intelligent modules, so that it can monitor input status and change output status to achieve control purposes. Compact structure, flexible configuration and powerful instruction set make S7-200 an ideal solution for various control applications.
The S7-200 CN series gives full play to its powerful functions in distributed automation systems. Use can range from simple controls replacing relays to more complex automation controls. The application fields are extremely wide, covering all industrial and civil fields related to automatic detection and automatic control, including various machine tools, machinery, power facilities, civil facilities, environmental protection equipment, etc.
To summarize: logo! It cannot replace plc, but plc can replace LOGO!