Safety Controller Design

In recent years, accidents of oil and gas pipeline occur frequently, causing serious loss of life and property and environmental pollution with very serious consequences. In the oil and gas pipeline monitoring system, the safety controller can effectively ensure safety and reduce losses caused by the accident.This article in accordance with the electrical/electronic/programmable electronic safety related systems functional safety standards IEC61508, makes hazard and risk analysis of oil and gas pipelines, and completes the design and development of the safety controller of the oil and gas pipeline monitoring system.Firstly, it introduces the basic concepts of functional safety and the application status of functional safety standards at home and abroad.Secondly, it gives an introduction of classification of source of hazard, the method of hazard and risk analysis and how to determine the safety integrity level.Thirdly, the paper introduces hardware design and software programming of a system based on AT89s52. The controller's structure is 1 out of 2. The hardware collects the 4-20mA current signal of the sensor, monitoring the temperature and the pressure of the oil and gas pipelines. The output of the safety controller once is 8-bit digital signal. Through RS-232, it can make communication with the upper computer.Finally, in accordance with the IEC61508 standards, it estimates the failure rate of the safety controller to verify the required safety integrity level.The paper summarizes the main job in the last part, and introduces the deficiencies and the improvement rooms in the continued work.