High-integrity PLC controller based on function safety

The invention relates to a system structure of a high-integrity PLC controller based on function safety and a realization method thereof, and particularly discloses a high-integrity controller of which safety integrity level is SIL3. A controller module supports redundancy, and supports various low-requirement, high-requirement and continuous operation modes. The controller supports two types of deciding structures of 1001D and 1002D, the controller is realized by adopting dual CPUs on the whole, and the dual CPUs are approved by SIL3 safety integrity level. In 1001D decision, SIL3 level can be achieved by the controller by adopting single CPU, the other CPU is used for realizing safety communication between the controllers, and redundancy decision can be realized by the controller with two 1001D. On the aspect of hardware, a combination structure of the SIL3 level dual CPUs and programmable logic devices is mainly adopted. Communication of the dual CPUs in the controller and communication of the controller and external modules can be realized via the programmable logic devices. According to the controller meeting the requirements of SIL3 function safety integrity level, high requirements for function safety integrity level in a critical control system and a high safety requirement system can be met.