Patent ID: 7529459

Claim:
A method for enforcing a reset in a non-mechanical spring-based actuator used in an optical attenuation system, the method comprising: detecting if a power supply is being cut off accidentally or intentionally; turning on an auxiliary power supply to continue energizing other components in the actuator; and sending a control command to instruct the actuator to be tuned to a reset position or a docking location, wherein the auxiliary power supply is a battery, electrical energy discharged from a circuit, or a separate power line that guarantees a power backup all the times, said detecting is performed by a power failure detection circuit, in an event of the power supply being lost, the power failure detection circuit first detects the event and sends a signal to a device driver that triggers the auxiliary power supply to energize other components in the actuator that needs to be powered, and at the same, the device driver is configured to send a control command to instruct the actuator to be tuned to a reset position or a docking location.