PID control of PLC
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How to implement PID control using Siemens’ 300 PLC? Please give me some advice! ! ! !
Using the built-in FB41 module in the library, it is also necessary to create a corresponding background DB
The PID control provided by PLCs is generally a relatively basic function. For problems related to setpoint tracking similar to disturbance-free switching, such as stopping calculations when the 4-20mA signal for PV or OUT is short-circuited or open-circuited, it is generally necessary to write programs oneself (using ladder diagrams, STL, etc.). It is recommended to learn more about the functions available in the PID modules of DCS, before attempting to implement similar functions in a PLC (the core PID algorithm can make use of the system’s built-in function blocks).
If that really isn’t possible, you can also write it yourself; after all, everyone understands the principles behind PID numerical algorithms. Using SCL means there aren’t many lines of code required, and it’s also possible to add or remove functions as needed. I used to write such code myself when working on projects. . . .
Could someone provide some examples for everyone to learn from and discuss?