With the MNL VAV controllers, does the integral damper motor perform a self calibration during which it cycles fully closed or fully open?

Issue

With the MNL VAV controllers, does the integral damper motor perform a self calibration during which it cycles fully closed or fully open?

Product Line

TAC I/A Series

Environment

MNL VAV controllers

Cause

When main power is applied to the MNL VAV controller, the damper motor will cycle to a full closed position.

Resolution

Automatic Calibration: An internal calibration feature automatically synchronizes the actuator position whenever the actuator is commanded to the full closed (0.0%) or full open (100.0%) position by continuing to drive the actuator in the requested direction for a time period of at least one additional complete full stroke drive time. If during this “end of stroke” drive period the Input value changes to a value within the control range, the output drive to locate the true end of stroke operation is terminated.

Drift Compensation Enable: Setting the Drift Compensation Enable configuration property to On (1) compensates for floating actuator mechanical drift whenever the actuator remains at the full open or full closed position for extended periods of time. Drift compensation is done by periodically driving the actuator in the commanded direction for a time period derived from the Drive Time assigned. Drift compensation does not occur whenever the actuator is within the actual control range between full open and full closed.

Refer to the Floating Actuator Object in F-27254 for additional information.