Description
PLC的程序一般不能按事先设定的循环周期运行。PLC程序是从头到尾执行一次后又从头开始执行。（现在一些新型PLC有所改进，不过对任务周期的数量还是有限制）而DCS可以设定任务周期。比如，快速任务等。同样是传感器的采样，压力传感器的变化时间很短，我们可以用200ms的任务周期采样，而温度传感器的滞后时间很大，我们可以用2s的任务周期采样。这样，DCS可以合理的调度控制器的资源。
Alcatel OS7700-CMM OmniSwitch 7700 Chassis Mgmt Module
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Lucent Avaya P334T-ML 700228125 Stackable Switch 334T
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Alcatel OS7-ENI-FM12 OmniSwitch 7000 12-Port 100BaseFX
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Cisco PWR-GSR10-AC 34-1645-01 2400W AC C12000 12410
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