Cascade control with bumpless mode transfer

CASCADE CONTROL with bumpless mode transfer

Cascade control is used when there is some secondary variable (pv S) available together with primary process variable (pv = pv P). The secondary variable has lower dead-time than the primary one with respect to manipulated value (mv = mv S). The cascade control consists of inner/secondary controller (PIDU S) and the outer/primary controller (PIDU P). If the CAS constant is set to 1, the primary controller controls the process output using secondary controller. The primary controller output is the setpoint for secondary controller which controls the process variable. For proper performance, the primary controller integrator wind-up must be handled.


How to start the simulator?

Before starting the simulator (applet) by START start.gif, 648B button, the sampling period can be set in the field Sampling time. The continous applet running can be stopped by STOP stop.gif, 666B button or paused by PAUSE pause.gif, 1,1kB button. The simulation speed can be adjusted by the slider. The re-init button reinit.png, 858B reset all parameters to initial state.

All parameters of active blocks (non-shadow) can be changed in the dialog which is invoked by cliking at the block. Detailed description of block parameters is available in Function blocks reference manual.