Data processing: measuring – calibrating – or testing – Measurement system – Performance or efficiency evaluation
Reexamination Certificate
2002-06-21
2004-10-05
Wachsman, Hal D (Department: 2857)
Data processing: measuring, calibrating, or testing
Measurement system
Performance or efficiency evaluation
C702S183000, C702S056000
Reexamination Certificate
active
06801877
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to predictive maintenance systems and methods, and more particularly to computer-based data collection systems and methods for measuring and collecting vibration data from machines.
BACKGROUND OF THE INVENTION
Data collection systems and methods are now widely used for measuring and collecting vibration data from machines, for predictive maintenance purposes. Data collection systems typically include two major components: a portable data collector and a host computer. The portable data collector is typically a dedicated instrument to which accelerometers can be coupled, and which stores accelerometer-based vibration data for a machine. An example of a state-of-the-art data collector is the EMONITOR® dataline™ data collector marketed by Entek Scientific Corporation, assignee of the present application. The EMONITOR® dataline™ data collector is described in a manual entitled “
EMONITOR® for Windows EMONITOR® dataline
™ (
U.S.
)
Data Collector User's Guide, First Edition
1995”, Manual No. EEW2501A, published by Entek Scientific Corporation, the disclosure of which is incorporated herein by reference.
The host computer is typically a standard PC-based computer which runs predictive maintenance data management and analysis software thereon. The host software allows a user to set up a database to model the machinery for which vibration data is to be obtained. The software allows lists of machines to be set up for data collection. Each list includes a set of measurement parameters that control where and how to take and store a measurement. The host software allows one or more lists to be loaded into the data collector for collection. The user then takes the data collector to a machine to be measured, accesses the measurement parameters for that machine, and collects and stores vibration and other information. After collection, the data is unloaded from the data collector to the host. The host software then allows the data to be analyzed. Reports can be generated, including reports of measurements that exceed alarms. Graphical displays of the data can be produced, including trend, spectrum, frequency trend, time waveform and spectrum map plots.
An example of data management and analysis host software is EMONITOR® for Windows, which is marketed by Entek Scientific Corporation, the assignee of the present invention. The EMONITOR® for Windows software is described in a manual entitled “
EMONITOR® for Windows User's Guide, Second Edition
1994”, Manual No. EEW0002B, published by Entek Scientific Corporation, the disclosure of which is incorporated herein by reference.
In state-of-the-art manufacturing environments, the capital investment in machinery can be staggering. Accordingly, there is a great need for predictive maintenance to prevent machine breakdowns and increase reliability. Moreover, with “just in time” manufacturing requirements, predictive maintenance becomes even more critical to eliminate machine down time. Accordingly, there is a great need for data collection systems and methods.
Unfortunately, the high cost of data collection systems is often a barrier to their widespread use. The high cost is in part related to the use of special purpose hardware and software in the data collector. In addition to high cost, the use of special purpose hardware and software limits the flexibility of the data collector and makes it difficult to update and improve the data collector. Although portable computers, laptop computers, pen-based computers, palmtop computers and Personal Digital Assistants (PDA) have become widely available, they have not yet made a significant impact on data collectors. See for example, the publication in Automatic ID News, April 1995, entitled “
Be Ready for Technology Leap at the End of the Century: Three Non
-
ADC Developments to Springboard Automatic Data Capture Growth”
. See also the publication in Maintenance, January/February 1995, by Billson et al. entitled “
Portable Pen Computers—An Essential Tool for the Mobile Maintenance Engineer”.
SUMMARY OF THE INVENTION
The present invention is a portable, self-contained data collection system for measuring and collecting vibration data from machines. The system includes an accelerometer including a motion sensitive transducer and an accelerometer output. The accelerometer is coupled to a machine to produce an analog signal at the accelerometer output. The system also includes a data acquisition card having an analog input and a digital output. The accelerometer output is electrically coupled to the analog input. As used herein, electrical coupling includes wireless, optical or conventional wire coupling. The data acquisition card samples and digitizes the analog signal to produce a time domain digital signal, i.e. a sampled and digitized series of voltage versus time points, at the digital output. The system also includes a battery-powered portable computer such as a pen-based computer, which includes an expansion slot. The data acquisition card digital output is electrically and mechanically connected to the expansion slot.
The battery-powered portable computer also includes a database having machine identifications and associated measurement parameters. User input means such as a pen allows user selection of a machine identification for measurement. The portable computer also includes signal processing means for processing the time domain digital signal according to the measurement parameters associated with the selected machine identification. Preferably, the signal processing means processes the time domain digital signal to produce a frequency domain digital signal by performing a Fast Fourier Transform (FFT), wavelet or other digital signal processing operations. Finally, the battery-powered portable computer also preferably includes signal analyzing means for analyzing the frequency domain digital signal to produce predictive maintenance information such as spectral distribution. The time domain digital signal can also be analyzed to produce crest factor and other predictive maintenance information.
A data collection system according to the present invention uses a standard portable computer such as a pen-based computer and a standard data acquisition card such as a PCMCIA sound card, to provide portable self-contained hardware for data collection and analysis. The machine database, signal processing means and signal analyzing means are preferably implemented using software modules which execute on the portable computer. The machine database and the signal analyzing software may be provided using EMONITOR® for Windows or other predictive maintenance software on the portable computer. Signal processing software may be provided by conventional digital signal processing software which provides digital filtering, integration from acceleration to velocity or displacement units, Fast Fourier Transform or other mathematical functions, and averaging. Accordingly, a low cost self-contained data collection system is provided.
It will be understood that since the portable data collection system includes a database, signal processing software and signal analyzing software therein, a host computer connection is not required for operation. Rather, all predictive maintenance operations may be performed using only the portable self-contained data collection system. However, it will also be understood by those having skill in the art that the portable self-contained data collection system can be used as part of a networked data collection system wherein the portable computer includes transmitting means for transmitting at least one of the machine identifications, the measurement parameters, the time domain digital signal, the frequency domain digital signal or the predictive maintenance information to a second computer. The second computer may store this data for distribution to other users and the second computer or other users may also perform one or more of the processing functions of the portable data collector. The transmitting means is preferably wireless,
Bates Andrew J.
Schiltz Richard L.
Watkins Jeffery P.
Entek IRD International Corporation
Wachsman Hal D
Wood Herron & Evans LLP
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