Expert ForumsInstrumentation and Control

Topic: Re: Can you explain a split range controller?

posed by 
Split range is a control configuration where a single PID controller outputs to two control valves that are usually not the same size, but could be.  In most split range applications, the controller is adjusting the opening of one of the valves when its output is in the range of 0 to 50% and the other valve when its output is in the range of 50% to 100%.   For a detailed discussion of split range, refer to Advanced Process Control:  Beyond Single-Loop Control by Cecil L. Smith, published by John Wiley & Sons, 2010.  Chapter 3 is dedicated to split range control. An example of a split range application is controlling the temperature of a vessel with both a heating mode and a cooling mode.  One control valve adjusts the rate of heating; the other control valve adjusts the rate of cooling. The description of your application is rather sketchy, but I doubt that split range is appropriate.