All controllers must can be used as shown in the figure below. The upper part shows a continuous time controller and the bottom part shows a discrete time controller.
1. | An error signal is generated with a plus minus element. Its serves as an input of the controller. |
2. | The controller output is connected with the process input. |
As shown in the figure, analog to digital convertors and digital to analog convertors should be used, when connecting a discrete-time controller to a continuous-time process.
1. | A setpoint signal is connected with the SP port of the controller. |
2. | The process output is connected with the PV port of the controller. |
The controller output is connected with the process input.
As shown in the figure, analog to digital convertors and digital to analog convertors should be used, when connecting a discrete-time controller to a continuous-time process.