Automatic level control system and method

摘要

An automatic level control system and method provide continuous proportional control of an inlet valve when the level of material in a storage container is between low and high limits. The system includes a main feedback loop and a nested feedback loop to insure proper control of the inlet valve through which material is added to the storage container. The main feedback loop provides a control signal indicating the desired setting of the inlet valve, and the nested feedback loop provides a control signal indicating the actual position of the inlet valve so that the two control signals can be compared for use in accurately moving the inlet valve to the desired position. The main feedback loop includes a computer into which different density values can be input for accurately determining the amount of material in the container as indicated by a weight sensor.