另外想问一下看到有些手册上说PV的值得采集频率最好是PID的5~10倍，有必要吗？
只要PV的采集周期高于PID的周期不就可以了吗？这样pid能够采集到不同的值。为什么要求这么高呢？
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问题补充：
连接怎么无法打开
最佳答案
提供了资料应该能有所帮助，
htTP://www.bgu.ac.il/chem_eng/pages/Courses/oren%20courses/Chapter_10.pdf
Cascadecontrolcanimprovecontrolsystemperformanceoversingle-loOPControlwhenever
either:(1)Disturbancesaffectameasurableintermediateorsecondaryprocessoutputthat
directlyaffectstheprimaryprocessoutputthatwewishtocontrol;or(2)thegainofthe
secondaryprocess,includingtheactuator,isnonlinear.Inthefirstcase,acascadecontrol
systemcanlimittheeffectofthedisturbancesenteringthesecondaryvariableonthe
primaryoutput.Inthesecondcase,acascadecontrolsystemcanlimittheeffectofactuator
orsecondaryprocessgainvariationsonthecontrolsystemperformance.Suchgain
variationsusuallyarisefromchangesinoperatingpointduetosetpointchangesorsustained
disturbances.
串级PID百度搜搜，资料蛮多的
提问者对于答案的评价：
thankyou
