Single Pid Controller; Reverse Acting Single Pid Control; Appendix B - ABB AX410 User Manual

Single and Dual Input Analyzers for Low Level Conductivity
AX410, AX411, AX413, AX416, AX418, AX450, AX455 & AX456

Appendix B

B.1 Single PID Controller
The single PID controller is a basic feedback control system using three-term PID control with a local set point.
Control Set Point
Process Variable
Fig. B.1 Single PID Controller
B.1.1 Reverse Acting Single PID Control
Reverse acting control is used when the process conductivity is less than the required output conductivity.
100%
Control
Output
0%
0%
Fig. B.2 Reverse Acting Single PID Control
78
PID Control Loop
Reverse
Acting
Process Variable Range
Manual Output
PID Output
50%
Appendix B
Output 1
100%
IM/AX4CO Issue 11