Browse Prior Art Database

Document Sensor Diagnostic

IP.com Disclosure Number: IPCOM000078862D
Original Publication Date: 1973-Mar-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 38K

Publishing Venue

IBM

Related People

Johnston, DL: AUTHOR

Abstract

A control processor is used to check the operation of document sensors in a transport, without using conventional test instruments. This technique tests the path to the light source and the return path from the light sensor under logical control.

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Document Sensor Diagnostic

A control processor is used to check the operation of document sensors in a transport, without using conventional test instruments. This technique tests the path to the light source and the return path from the light sensor under logical control.

A diagnostic program is entered into control processor 1. External registers 2 provide an interface between the control processor and the hardware. Initially the program turns on driver 3, which turns on all of the light-emitting diodes (LED's). Sensors S view the light energy from their respective LED's, emitting a signal when light is present. This signal is amplified and fed into analog-to-digital converters (A/D) which in turn feed logical signals back to an external register 2. The program sequentially tests all units for an output. The absence of an output stops the program and displays the location of the faulty unit on display 4. If all outputs are valid, the program moves on to the next phase of the test.

Next the program turns off driver 3 which turns off all LED's. The units are sequentially tested for absence of output. If an output occurs, a faulted-on sensing unit is indicated and the location displayed on display 4. Under normal operating conditions, the diagnostic system is disabled. The machine controls are monitored directly from the operating program in the control processor.

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