Design And Implementation Of Embedded Security PLC Based On ARM+FPGA

Traditional PLC system is easily interfered in the process of performing industrial control and the execution errors cannot be dealt with by better mechanism owing to its own limitations in system structure and processor performance,which prevents the industrial production.However,security PLC system has become the most vital part of the current industrial control field,directing the future development of PLC system.The embedded security PLC system based on the high performance dual processor of ARM + FPGA proposed in this paper can greatly reduce the probability of system failure and improve the reliability of industrial control.Security PLC system is divided into hardware system and software system.The hardware system adopts a heterogeneous dual-channel security architecture based on a 1oo2 D redundant architecture,including the embedded ARM processors,FPGA-based RISC processors,watchdog circuits,security diagnostic circuits,dual-port buffer memory and redundant I/O channel circuits.When the PLC system is running,the ARM processor and the RISC processor are redundant to each other to execute the logic instructions to verify the output through the built-in judgment logic of the security diagnostic circuit.When the ARM processor fails,the RISC processor will take place of the PLC system to execute the real-time cycle logic,while the watchdog circuit will reset the ARM processor to ensure that the control program is performed reliably.PLC software system consists of two parts: the compilation system and the execution system.The compilation system is to compile the user-written ladder logic instruction and logic instruction into the machine executable code which matches the hardware system.At the same time,the compilation also provides lexical analysis,syntactic analysis,and so on.The execution system outputs the correct processing output signals to the control device in order to complete the security control of the corresponding external machinery and equipments by implementing the generated machine executable codes of the compiler system.After systematic performance test,it is proved that the security PLC system can correctly execute the logic program and complete the control of the external device,which is very suitable for the numerical control system.