Modulate

To adjust by small increments and decrements.

Modulating Control

A step modulating control that is capable of controlling flow rate between the maximum and the minimum adjustable input rate in response to varying heating or cooling load.

Method of control in which the output of the controller may vary infinitely over its range.

Modulating Control Valve

A valve capable of increasing or decreasing by increments the fluid flow according to deviation from the set control value.