Browse Prior Art Database

Count Up Count Down Error Detect Circuit

IP.com Disclosure Number: IPCOM000087029D
Original Publication Date: 1976-Dec-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 32K

Publishing Venue

IBM

Related People

Brown, ET: AUTHOR

Abstract

This circuit detects missing emitter pulses, extra emitter pulses, and a print head running into the side plates due to electrical or mechanical failures. It makes use of the linear emitter outputs on the printer. The ANDing of expected motor control direction and the opposite actual sequence results is a characteristic of the operation. The control unit determines, from the linear emitter sequence, which direction the print head is traveling and this information is used to create a count up/count down error check.

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Count Up Count Down Error Detect Circuit

This circuit detects missing emitter pulses, extra emitter pulses, and a print head running into the side plates due to electrical or mechanical failures. It makes use of the linear emitter outputs on the printer. The ANDing of expected motor control direction and the opposite actual sequence results is a characteristic of the operation. The control unit determines, from the linear emitter sequence, which direction the print head is traveling and this information is used to create a count up/count down error check.

A count up sequence, when the head moves from left to right, involves signals representative of emitter 1, emitter 2, emitter 3, then emitter 1, etc., on lines 1-3. A count down sequence, when the head moves from right to left, involves emitter 1, emitter 3, emitter 2, then emitter 1, etc.

If the control unit is stepping the print head motor in a left-to-right direction, evidenced by a signal on line 4, and a count down sequence (line 5) occurs, then the circuit activates the Count Down Error line 6. If the control unit is stepping the print head motor in a right-to-left direction, indicated by a signal on line 7, and a count up sequence (line 8) occurs, then the circuit activates the Count Up Error line 9.

The control unit and programs use the outputs of this error circuit to start an error recovery routine.

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