Adaptive doubles and length measurement techniques and apparatus

Abstract

Sheet handling and counting apparatus includes a control system having master and slave processors. The slave processor continuously examining passing sheets to measure sheet length and look for doubles. The slave processor generates outputs representative of jam, doubles error, length error and diagnostics as well as detecting the presence of a check separator for stopping the sheet handling and counting apparatus. The master processor controls the sheet apparatus in accordance with the status signals developed by the slave processor, as well as other data derived from sensors interfaced with the master processor. The master processor transmits a control word to the slave processor to control operation of the length measurement according to one of a plurality of selectable tolerances and to select one of a plurality of operating modes for detecting doubles. The slave processor transmits a multibit code word representing the result of the length, doubles and other evaluations for each sheet, the master processor controlling the apparatus in accordance with the evaluation data received from the slave processor. Adaptive techniques are utilized for both length measurement and doubles detection. The length measurement technique permits the accurate counting of sheets, even though they are skewed as they are fed through the apparatus.