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Marginal Device Performance Check for Pulse-Width Modulation Control Systems

IP.com Disclosure Number: IPCOM000052579D
Original Publication Date: 1981-Jun-01
Included in the Prior Art Database: 2005-Feb-11
Document File: 2 page(s) / 58K

Publishing Venue

IBM

Related People

Bailey, SE: AUTHOR [+4]

Abstract

Because of the availability of low-cost digital logic, pulse-width modulation (PWM) has been increasingly utilized to control power input to electromechanical devices. The failure mode in most such devices causes more and more power to be required to maintain some nominal condition or performance. Specifications for a device may include valid ranges for PWM. Devices approaching range limits over a period of time may be flagged as failing by software, whereas no visible indication of error is possible (i.e., the device still performs adequately but requires more power, thus a greater width on the pulses which are used to modulate the device).

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Marginal Device Performance Check for Pulse-Width Modulation Control Systems

Because of the availability of low-cost digital logic, pulse-width modulation (PWM) has been increasingly utilized to control power input to electromechanical devices. The failure mode in most such devices causes more and more power to be required to maintain some nominal condition or performance. Specifications for a device may include valid ranges for PWM. Devices approaching range limits over a period of time may be flagged as failing by software, whereas no visible indication of error is possible (i.e., the device still performs adequately but requires more power, thus a greater width on the pulses which are used to modulate the device).

After completing a service call, the serviceman may execute a hardware verification routine using software, as illustrated in the sketch. The pulse-width modulation for some nominal condition may be displayed. This value, when compared against its previous value or range limits, may indicate a potential failure of the device which will allow the serviceman to either replace it at that time or recognize that, at the next service call, the device should be replaced to bring it back within the service limits.

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