This module specifies the damper position in flow control modules and applications. This module accepts the following modes: close, open, hold, control, box flow test, and failsoft, and adjusts the output accordingly. If control is requested and the flow is unreliable, the module sets the damper position to a value proportional to the PD Max Position. Unreliable flow results in operation as a pressure dependent controller. Attempts to control near zero results in the damper being closed. The adjustable parameters provide a way for the user to configure the module to operate in the correct manner for control of any size damper.
This module also includes a Near Zero Flow feature. When commanded to Control and the Flow Setpoint is a value relatively close to zero, the module detects this and goes to a close mode rather than attempt to control near zero.
This module is implemented as a standard Control Activity with a nested Hybrid Activity.