共享一个西门子PLC上所使用的软件PID程序（FB58），我已将其改为C语言代码，
并已在关键地方附有中文注释，带自整定功能。
经测试，自整定后的PID参数非常好用，这就解决了繁琐的参数整定问题了。(Sharing a software PID program (FB58) used on Siemens PLC, I have changed it to C language code.
Chinese annotations have been attached to key places with self-tuning function.
After testing, the self-tuning PID parameters are very useful, which solves the tedious problem of parameter tuning.)