| 摘要 |
Elevator load is computed from sensors. These sensors provide load signals. The load, defined by a stored load equation, is the product of those signals with a gain signal, summed with an offset signal (S20). Load computation using those signals is improved by a recalibration routine. The routine to adjust the offset (S2-S10) is initiated when the car transits floors in an empty car condition (S2). Current equation offset and the latest empty car signal levels are compared (S6). If the difference is less than a reference (STEP) the last levels become the offset (S9); if not, the equation offset is changed (S7). Load computation is further improved by sensing car rollback, to correct the gain signal. Rollback may occur after the brake holding the car in position is released but before a speed dictation signal is given to the motor, causing the car to move if motor torque is not matched to the load as computed from the load equation. Depending on the magnitude of the rollback, the gain is increased or decreased in increments (S23-S41) through successive elevator stops at floors provided there is sufficient passenger (cab) load. Rollback not caused by incorrect motor pretorquing when the brake is released is discarded (S21) by comparing the actual change in position of the car with the change in motor shaft or sheave position. |
