Method and system for determining an offset between a detector and a point on a motor

A method for determining an offset between a detector and a point on a motor, the movement of the point on the motor being impeded in at least one direction, the method comprising performing the steps of:

• a) setting a test value for the offset to a first value;
• b) based on the test value, causing a displacement of the detector and measuring that displacement;
• c) performing one of the steps of:
• i) repeatedly increasing the test value and performing step b) for each so increased test value until it is determined that the displacement of the detector measured for that test value has crossed a threshold from a given direction, wherein the given direction is either from above or below the threshold, and determining a first crossing value indicative of the test value at which it was determined, in step i), that the displacement of the detector had crossed the threshold;
• and
• ii) repeatedly decreasing the test value and performing step b) for each so decreased test value until it is determined that the displacement of the detector measured for that test value has crossed the threshold from the given direction, and determining a second crossing value indicative of the test value at which it was determined, in step ii), that the displacement of the detector had crossed the threshold;
• d) performing the other of the steps of i) and ii);
• and
• e) determining the offset based on the first and second crossing values.