Arrangement for monitoring and controlling the extent and direction of movement of a forms feed assembly in a printer sub-system cooperating with a data processing system.

摘要

The arrangement according to the invention is provided with facilities for detecting emitter changes that have occurred during operating intervals. in a typical operation, a microprocessor (210) initiates a command to a moving assembly (170), such as a forms feed assembly, then once the operation is initiated the microprocessor transfers to other responsibilities, meanwhile periodically checking the status of the forms feed assembly. The forms feed assembly supplies emitter signals to the processor which are utilized by the microprocessor to determine whether or not any emitter changes have occurred during the intervals between the checking operations. The microprocessor has a stored data table and logic responsive to emitter signal conditions that had previously occurred (WAS) and that is further responsive to emitter signals that are presently occurring (IS) to supply an output in numbers of emitters indicative of both the extent and direction of movement of the assembly during the intervening interval.