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Safety Design Method of PLC Control System

Although the operation of PLC is safe and reliable,as a system,stability and reliability is still a problem that cannot be ignored.The system safety design should make full use of the characteristics of PLC,so that the operation of PLC can be truly safe and reliable.

(1)Hardware protection.Mainly include:interlock protection,limit protection and emergency stop protection.

(2)Software protection.Mainly include:interlock protection,limit protection,time limit protection and self-check protection.PLC is controlled by the stored program,and the stored program is used for installation protection,and it can also make it only perform the correct operation and reject the wrong command.Software protection mainly uses self-check information to find hidden dangers and clear faults in time;it can also compile diagnostic programs to eliminate faults according to the characteristics of the project to ensure reliable,stable and safe operation of PLC.

PLC控制系统的安全设计方法

尽管PLC的运行是安全、可靠的，作为一个系统来说，稳定可靠仍然是不可忽视的问题.系统安全设计要充分利用PLC的特点，使PLC的运行能真正达到安全、可靠。

(1)硬件保护。主要包括：联锁保护、限位保护和急停保护等。

(2)软件保护。主要包括：联锁保护、限位保护、限时保护和自检保护等。PLC是利用存储程序进行控制，用存储的程序进行安装保护，也可以使其只执行正确的操作，而拒绝错误的命令。软件保护主要利用自检信息及时发现隐患，清除故障;也可针对工程的特点，自编诊断程序而排除故障，以确保PLC可靠、稳定、安全运行。