This paper gives the detail description of the safe system structure and its function in the oil field automation. Also, it gives the basic steps for safety system design by using PLC.

这篇文章对安全保护系统在油田自动化中的作用及组成给予了详细的描述，也给出了用PLC设计安全保护系统的基本步骤。

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This system of policy-making plays safe, keeping everything well within the boundaries of the official party structure.

ECONOMIST: Conservative Party: Six brains | The