Split range control system or Duplex Control
Split range controller has one input and two output.
Split control divides the controller output in to two distinct functions.
Heat/Cool controllers are one example of split control.
When PV is equal to SP and error is zero,the H/C signal is at 50%.
If the value of the PV decreases below SP,the H/C signal increases proportionally.
If the value of the PV increases above SP,the H/C signal decreases proportionally.