Pen turret control system
AssigneeSanders Associates, Inc.
InventorsCharles Gunderson, Aftab H. Kapadya
Life of this patent
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Abstract
A control system for controlling a turret head in a pen plotter wherein the turret head and pen holder move in combination with the pen carriage to provide turret selectability at the writing site. Sensors and associated logic are provided for detecting the presence of a turret on the pen carriage, for sensing the presence and absence of pens in the turret and in the pen holder, for detecting the type of pen or other writing device being used and taking appropriate action responsive thereto, and for applying varible damping constants to the movement of the turret head. Control logic is disclosed for assuring reliable and optimum operation.
Claims7
In a graphics plotter having a turret for releasably holding a plurality of writing devices and a pen holder for exchangeably obtaining writing devices from the turret where the turret and holder are moved in combination on a pen carriage, said turret is rotated by a logic controlled stepping motor, the pen holder is raised and lowered by a logic controlled electromagnetic coil, and the pen carriage is moved by a logic controlled drive motor, the improvement comprising:
- (a) first sensor means for detecting the presence and absence of a turret on the pen carriage and for producing a signal indicating same;
- (b) second sensor means for detecting when the turret is in a home position and for producing a signal indicating same;
- (c) third sensor means for detecting the degree of proximity of the pen holder to raised and lowered positions and for producing a signal indicating same;
- (d) fourth sensor means for detecting the presence or absence of writing means at addressable positions of the turret relative to said home position, for detecting the presence or absence of writing means in the pen holder, for determining the type of writing device in the pen holder, and for producing signals indicating same;
- and,
- (e) variable current source means connected between the logic and the electromagnetic coil for controlling the position of the pen holder and the downward pressure on a writing device in the holder.
Dependencies are inferred from the claim text.