摘要 |
A woodworking apparatus includes a computer based control unit for absolute positioning of tool units located in longitudinally spaced relationship to one or both sides of a conveyor. Absolute position sensors are connected to each axis of tool movement. Each axis has a separate permanent magnetic motor to position the tool on the corresponding axis. A multiplexing board selectively connects each sensor to the computer and a multiplexing position motor drive board selectively connects the corresponding motor in a closed loop absolute position control. Each position sensor includes spaced Hall cells secured to a movable sensor head, with limit signals hardwired via the multiplexing board directly to the control system. The PM motor is a low cost motor which rapidly drives the tool unit in accordance with the output of the sensor. The motor drive system includes a fast drive mode in an open loop for rapidly moving the several tool units and sequentially to slowly move the tools to the final position. Thus, the computer based control unit is provided with individual input commands for each axis of the tool unit and positions all the tool units in a matter of 3 to 8 minutes.
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