Position controller for glass sheet processing system

In a glass sheet processing system, a position controller for positioning a movable component driven by a variable speed drive, the position controller being adapted for use with a central control system which monitors and controls the processing of the glass sheets, the central control system including a master computer having means for providing command signals and data signals relating to preselected end points, the position controller including a position encoder connected to the movable component, and a slave computer, the slave computer comprising:

• a first input connected to the master computer for receiving digital signals corresponding to positioning commands, position data and velocity profile data from the master computer;
• a second input connected to the position encoder for receiving digital signals corresponding to current position information from the position encoder;
• a first output connected to the variable speed drive for providing control signals to the variable speed drive;
• a second output connected to the master computer for transmitting digital signals corresponding to command acknowledgement, error, position data, and velocity profile data to the master computer;
• and
• logic means for calculating the distance required to position the movable component from the component's current position to a preselected point, calculating the desired current velocity according to position and velocity profile data for that preselected point, and calculating a digital control signal necessary to drive the variable speed drive to move the movable component to the preselected point at the desired current velocity in response to a positioning command received from the master computer, and transmitting an acknowledge signal to the master computer when the movable component has reached the preselected point.