Information on how the MNB-Vx determines damper position after a power cycle.

Issue

Information on how the MNB-Vx determines damper position after a power cycle.

Product Line

TAC I/A Series

Environment

MNB-V1 and MNB-V2

Cause

Understanding damper behavior after a power cycle

Resolution

After a power cycle, the damper does not know exactly where it is and it is NOT stored in non-volatile memory. So, it must drive open or drive closed to re-synch the hall effect sensors embedded in one of the gears that provides positional feedback.

There are two Hall-Effect sensors that detect a magnet, embedded in one of the drive gears, as it spins.
Each sensor sends a pulse to an internal counter each time it detects the passing magnet.
The two Hall-Effect sensors help with identifying clockwise and counter-clockwise rotation. The accumulated pulse count and the gear ratio help in calculating the damper position.

Right-click the VAV Actuator object in WorkPlace Tech and go to its Properties, there is a setting called 'Position Initialization Mode'. Select open or closed as the choice when initializing after a power cycle.