Sort gap control

1. A method of calibrating the control system of a sortation conveyor, the control system having control logic for the operation of the sortation conveyor, the sortation conveyor having a plurality of shoes and a conveying surface, a sort induct sensor and a first shoe sensor, the control logic including a representation of spacial correlation between the sort induct sensor and the first shoe sensor, the method comprising the step of:

a. placing the control system in calibration mode wherein calibration logic is executed;

b. introducing a plurality of articles on the conveying surface upstream of the sort induct sensor and the first shoe sensor, each article of said plurality of articles having a respective leading edge;

c. advancing the conveying surface so that the respective leading edge of each article is detected by said induct sensor;

d. assigning one or more respective pushers to each article, having a respective first pusher;

e. determining the respective distances between the respective leading edges of each article and that article's first pusher; and

f. calculating a calibration value based on the respective distances which is indicative of spacial correlation between the sort induct sensor and the first shoe sensor.

2. The method of claim 1 , comprising the step of stopping the conveyor prior to determining the distance between the respective leading edge of each article and that article's first pusher.

3. The method of claim 2 , wherein the step of determining the respective distances comprises the step of physically measuring the respective distances.

4. The method of claim 1 , wherein the step of determining the respective distances comprises the step of physically measuring the respective distances.

5. The method of claim 1 , wherein the step of assigning one or more respective pushers comprises the steps of diverting only pushers which are not assigned.

6. The method of claim 1 , comprising the step of adjusting the representation of spacial correlation of the control logic based upon the calibration value.

7. The method of claim 6 , comprising the steps of generating for each article a respective calculated distance between the respective leading edges of each article and that article's first pusher.

8. A method of calibrating the control system of a sortation conveyor, the control system having control logic for the operation of the sortation conveyor, the sortation conveyor having a plurality of shoes and a conveying surface, a sort induct sensor and a first shoe sensor, the control logic including a representation of spacial correlation between the sort induct sensor and the first shoe sensor, the method comprising the step of:

a. placing the control system in calibration mode wherein calibration logic is executed;

b. introducing a plurality of articles on the conveying surface upstream of the sort induct sensor and the first shoe sensor, each article of said plurality of articles having a respective leading edge;

c. advancing the conveying surface so that the respective leading edge of each article is detected by said induct sensor;

d. assigning one or more respective pushers to each article, having a respective first pusher;

e. generating for each article a respective calculated distance between the respective leading edges of each article and that article's first pusher;

f. determining for each article respective actual distances between the respective leading edges and that article's first pusher;

g. calculating a calibration value based on the respective distances which is indicative of spacial correlation between the sort induct sensor and the first shoe sensor;

h. adjusting the representation of spacial correlation of the control logic based upon the calibration value; and

i. repeating steps b through f.