The appropriate product category
- An action that changes the manipulated variable in proportion to the rate of the deviation (i.e., the slope with time as the horizontal axis) to prevent the deviation from increasing excessively. The proportional action and integral action correct the result of control. Therefore, proportional action and integral action respond slowly to temperature change. This is why derivative control is required. The derivative control action corrects the result of control by adding the control manipulated variable in proportion to the slope of temperature change. A large control manipulated variable is applied to radical external disturbances to get the temperature quickly back under control.