Characteristics Comparison of PLC and relay

In terms of application, plc uses microprocessor technology and communication technology, so it can be widely used in sequential control, motion control, communication, data management and other fields, and has extremely strong flexibility.

However, the application scope of relays is limited, and the solution to small problems is often complicated, which makes the control cabinet large, the reliability is reduced, and it is not flexible.

In terms of speed control, PLC is implemented by program instructions controlling the semiconductor circuit, so it is much faster than the relay circuit that uses the mechanical action of the contacts to achieve control, and there will be no jitter problems.

In terms of maintainability and reliability, the relay control logic circuit uses a large number of mechanical contacts and has too many connections, which deteriorates the maintainability and reliability of the system, while PLC uses microelectronic technology. A large number of switching actions are completed by an auxiliary relay software and non-contact switch, so the reliability is high. At the same time, because some PLCs are also equipped with self-checking and monitoring functions, it provides great convenience for on-site debugging and maintenance, saving Cost.

In addition, during construction and design, PLC is more convenient and time-saving than relays.