[求助-西门子PLC300/400] PID级联一般在什么情况下，考虑用到

amy328

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？</p>
        问题补充：
连接怎么无法打开

毕村内富

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
Cascade control can improve control system performance over single-loop control whenever
either: (1) Disturbances affect a measurable intermediate or secondary process output that
directly affects the primary process output that we wish to control; or (2) the gain of the
secondary process, including the actuator, is nonlinear. In the first case, a cascade control
system can limit the effect of the disturbances entering the secondary variable on the
primary output. In the second case, a cascade control system can limit the effect of actuator
or secondary process gain variations on the control system performance. Such gain
variations usually arise from changes in operating point due to setpoint changes or sustained
disturbances.
串级PID百度搜搜，资料蛮多的