The basic building blocks a feedback control system and its operating principle as applied in process measurement and control.
![The difference between G(z)H(z) and GH(z) G(z)H(z)=Z[G(s)]Z[H(s)] GH(z)=Z[G(s)H(s)]](https://i.pinimg.com/originals/cf/0f/f3/cf0ff34b44a25b2db3bbdae1ebdf3775.jpg)
