Design And Research Of Embedded PLC

Programmable Logic Controller (PLC) has been widely used, because of its simply programming, high reliability adaptability, etc., But with the development of technology, its limitations are also highlighted: poor compatibility and computing capability. So, as the hardware support platform of PC-used, Soft PLC has been invented, which using software technology to achieve the basic functions of the standard PLC. Soft PLC not only provides the same functionality as PLC, but also has an open architecture, more rich instruction and control module, more strong data processing ability and a strong network of communications. However, PC is lack of the ability of real-time and consistency,reliability. Designing a new type of PLC is the issue of the research now, which not only has conventional and real-time, but also has an open soft PLC and powerful function.Embedded PLC use embedded technology as its platform,and strengthen the computing capability of process control, offer an open extended structure.It has been integrated the chartacteristics of embedded platform and carry forward the advantages of PLC ladder language and the advantages of PC-open, Embedded PLC provides a common development platform for the solution of object control.Through the analysis of the PLC technology in the home and abroad, a solution scheme of Embedded PLC bases on embedded technology was proposed. The Emdedded PLC's hardware platform adoptes modular design of ARM chip, then the system will have good scalability. The user can select specific modules freely. By designing a rich communication interface, it can be able to in communicate with others by RS232, RS485, CAN bus and Ethernet. It can complete the underlying data transfer between PLC and PLC or devices to make the user build up the network conveniently. The design of embedded PLC usesμCLinux embedded operating system, and designed by the virtual machine (that is, embedded systems and user programs by adding a layer of abstraction between the virtual PLC) to achieve the implementation of the user program compiled to enhance the system's portability and versatility. INSPEC is used for monitoring platform of Emdedded PLC, the communication between Embedded PLC and INSPEC with internet. The driver is designed that bases on the Ethernet, to achieve the communication between Embedded PLC and INSPEC. Users can also remotely access Embedded PLC by embedded web server, which is established in the Embedded PLC, It can achieve real-time monitoring of field device.In this paper, A Frequency Control System was designed based on the Embedded PLC,and implemented the control of Embedded PLC on the Inverter,and carried out the upper monitoring and remote monitoring.The system is running well, and achieved the desired objectives. The experiment proves that the design is reasonable, and has a high value of application.