Description
ESD也不单是实现联锁关系，它应该凌驾于生产过程控制之上，具有独立性，这样降低了两者同时失效的概率，ESD的安全等级要高于DCS。DCS主要是：动态控制，故障自动显示，维修时间不太关键，可以进行自动/手动切换；ESD主要是：静态监测、保护，必须测试潜在故障，维修时间非常关键，必须始终在线，不允许离线。
Used: Sihi Vacuum pump, size 3×2, carbon steel, 6 stage
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