Electrified exit device

A method for adjusting input to a latch actuator by a controller in order to fully retract a door latch, wherein said latch actuator is a stepper motor, said method comprising the steps of:

• a) energizing said stepper motor at a predetermined input frequency, wherein said predetermined frequency corresponds to a predetermined motor indexing rate;
• b) measuring an actual motor indexing rate;
• c) comparing said actual motor indexing rate to said predetermined motor indexing rate;
• and
• d) reducing an input frequency if said actual motor indexing rate is less than said predetermined motor indexing rate to fully retract the door latch.

A method for adjusting input to a door latch actuator by a controller in order to fully retract a door latch, wherein said door latch actuator is a stepper motor and includes a sensor for detecting door latch binding, said method comprising the steps of:

• a) actuating said door latch actuator;
• b) determining by said sensor whether said door latch has retracted within a predetermined time limit after actuating said door latch actuator;
• wherein, if said door latch has not retracted within said predetermined time limit,
• c) changing actuating input to said door latch actuator without deactivating the door latch actuator to cause full retraction of said door latch.

A method for adjusting input to a door latch actuator by a controller in order to fully retract a door latch, wherein said door latch actuator is a stepper motor and includes a sensor for detecting door latch binding, said method comprising the steps of:

• a) placing said door latch actuator in an actuating mode;
• b) determining by said sensor whether said door latch has retracted within a predetermined time limit while said door latch actuator is in said actuation mode;
• wherein, if said door latch has not retracted within said predetermined time limit,
• c) decreasing signal input frequency to said door latch actuator and maintaining said door latch actuator in said actuation mode;
• d) increasing an output torque of said door latch actuator by said decreased signal input frequency;
• and
• e) causing full retraction of said door latch by said increased output torque.

A method for adjusting input to a door latch actuator by a controller in order to fully retract a door latch, wherein said door latch actuator is a stepper motor and includes a sensor for detecting door latch binding, said method comprising the steps of:

• a) actuating said door latch actuator to impart a first output torque to retract said door latch;
• b) determining by said sensor whether said door latch has retracted within a predetermined time limit after actuating said door latch actuator;
• wherein, if said door latch has not retracted within said predetermined time limit,
• c) decreasing signal input frequency to said door latch actuator so that door latch actuator imparts a second output torque causing full retraction of said door latch, wherein said second output torque is greater than said first output torque.