Abstract: A printer control system uses two microprocessors and a print control for operating a plurality of print hammers in synchronism with a revolving type carrier. One microprocessor is a mechanical control processor, the print hammers are operated by a self timed print control system and the other microprocessor is a print control processor that communicates with a host system for receiving print and control data used by the print control and the mechanical control processor for operating the printer. The mechanical control processor monitors a speed selection device such as an operator panel with speed control keys and operates controls for operating drive means for moving the type carrier at selected speeds. The print control processor supplies speed control data from a diskette to the mechanical control processor for control the type carrier speed.

Abstract: A positioning system for a line printer uses dc servomotors for driving a forms feed mechanism in increments of one or more line spaces at a time. The system includes a microprocessor and a position counter that counts either 1/4 or 1 degree displacement pulses generated by a motion indicating means including optical transducers and an emitter disk coupled to the motors. The motion indicating means includes an error hold and compensation counter that counts and stores 1/4 degree pulses generated during error movement of the motors relative to a stop position during the uncontrolled state and supplies a corrected 1 degree pulse to the position counter upon start up.

Abstract: Servo control circuit for a DC motor having programmable timers to control the motor energizing period independently for each unit of shaft displacement. The circuit includes timer-gated latches to signal below-speed and above speed conditions and override the timer control period to reestablish the desired velocity.