Control Loop Foundation

Batch and Continuous Processes -
Interactive Source for Process Control

Ratio Control

This workshop is designed to allow the operation of ratio control to be explored. The process stream concentration is maintained at setpoint through the regulation of the blended streams ratio setpoint.

Step 1. In the ratio control workspace, change the mode of the Ratio block to Auto.

Step 2. Change the Ratio SP (setpoint) over the following range: 0.3, 0.5, and 0.8. Observe the change in the blend flow and the process outlet concentration. Then set the Ratio SP to 0.5 and wait for the concentration to settle to a steady value.

Step 3. Make a step change in the FEED and observe the way the ratio changes the dependent loop. Did the concentration change?

Step 4. Change the ratio block to cascade mode. Change the setpoint of the analytical loop to 40% and observe the impact on the ratio setpoint. Does the measured concentration reach setpoint?