Data processing: measuring – calibrating – or testing – Measurement system – Performance or efficiency evaluation
Reexamination Certificate
2000-02-14
2003-01-14
Wachsman, Hal (Department: 2857)
Data processing: measuring, calibrating, or testing
Measurement system
Performance or efficiency evaluation
C702S189000, C702S183000, C702S056000, C073S660000
Reexamination Certificate
active
06507804
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to a method and apparatus for compressing measurement data correlative to machine status, and in particular, to a method and apparatus for compressing machine vibration data to allow significant compression of the original data for storage and transmission wherein the compressed data can be retrieved and reconstructed to provide a complete continuous waveshape history of machine performance.
BACKGROUND OF THE INVENTION
Machinery monitoring systems have been permanently installed in, inter alia, today's large process plants, power generation stations and pipelines in an attempt to provide machinery protection by continuously monitoring the behavior and performance characteristics of machinery at a multiplicity of points and possibly acquiring data from these points simultaneously. More recently, the trend has been to enhance the monitoring systems by directly interfacing computers to the systems for periodically collecting data from these systems for historical trend, machinery diagnostics and predictive maintenance purposes. However, these current systems use methods which only retain a small history of machine performance at best.
For example, current systems periodically collect, store, display and print machinery data in a variety of formats using a variety of schemes. One such scheme is to continuously sample and store data at a high sample rate to obtain data with relatively high data time resolution, and as storage space fills, to replace the stored data with a new data set. This scheme does not automatically store the historical information necessary to analyze one or more problems, may not represent a long enough period of time to represent the on-set of one or more problems and does not readily identify the occurrence of one or more problems.
Another scheme is to intermittently capture data “snapshots” of the machine performance. A small set of “snapshots” are maintained in memory and saved in the event of a machine problem. However, the time represented by the “snapshots” may not be adequate to represent historical machine performance or may not represent a continuous set of data with the machine fault occurring between data sets previously stored in memory.
A common scheme is to represent the machine performance with an overall magnitude, eliminating all of the details that are contained to generate the magnitude. Although the magnitude can be used for protection, it does little to identify the causes of the problem.
The disadvantage of these schemes is they either consume too much memory, may not provide a rapid method to identify when one or more problems commence and to describe its progress or may lose the ability to diagnose one or more problems after the fact by either destroying the data with replacement information, or by taking data samples with the data of interest falling between the samples.
Therefore, if one were to continuously capture the machine data using current techniques, the memory requirements of such data storage can be enormous considering that the data is preferably collected over a period of months or years. In addition, long transmission times are required for transmitting large quantities of continuous machine data to a remote data base for permanent storage and with enough detail and history to perform fault analysis and diagnosis.
In addition, with current systems it is a challenge to capture and store infrequently occurring machine anomalies and to ensure that these anomalous events get managed using past learning experiences and procedures according to historical data. For example, the cause of and the procedures needed to deal with these machine anomalies may not be repetitive enough to stay within peoples' memory. Further, to make matters worse, many anomalous events occur so infrequently that people who managed and learned from previous situations have either changed jobs or are not available by the time a similar anomalous event occurs again. These anomalous events can have a profound impact if not managed correctly. For example, improper management of one of these anomalous events may cause loss of life, loss of property, fugitive emissions and other undesirable consequences.
Therefore, what is needed is a system which, inter alia, allows machine data to be compressed and stored in a reduced form which represents a continuous set of data correlative to a continuous history of machine performance without allowing machine faults between data sets to go undetected and thus unrepresentable. In addition, a need exists for a system which reduces data volume sufficiently to allow transmission using commonly available transmission media. Furthermore, a need exists for a system which allows stored compressed data to be retrieved and reconstructed to provide a complete continuous waveshape history of machine performance. Moreover, a system is needed which provides continuous data acquisition for diagnostic and predictive maintenance purposes for maximizing the machine's life while minimizing its cost and averting any catastrophic events when in operation.
U.S. Pat. No. 4,908,785 issued Mar. 13, 1990, to Cubbins, et al., teaches the use of a data compression method for telemetry of vibration data. The method achieves compression by filtering the incoming signal to extract a low frequency band. This low frequency band is sent to a multiplexed system without encryption or compression but can be sampled at a lower frequency since the upper frequency has been significantly reduced. The total range of frequencies is then divided, either by fractional octave filters, DFT or FFT to amplitude detect bands of frequencies and then the magnitude of the signals in this band or bands are extracted. These magnitudes are multiplexed with the lower frequency signals to give an overall or specific distribution of energy. Once processed, the low frequency data can be extracted but a waveshape can not be generated from the information present.
SUMMARY OF THE INVENTION
The present invention is distinguished over the known prior art in a multiplicity of ways. For one thing, the present invention provides a system for compressing, storing and transmitting raw dynamic machine data in a reduced form which can be retrieved and reconstructed into a continuous set of data correlative to a continuous waveshape history of machine performance without allowing machine faults between data sets to go undetected and thus unrepresentable. In addition, the present invention reduces data volume sufficiently to allow transmission using commonly available transmission media by, inter alia, retaining only significant data and by eliminating data created from noise sources. Furthermore, the present invention provides a system which continuously collects and stores information on machine performance to generate a historical data base which captures, inter alia, infrequently occurring machine anomalies and allows historical dynamic machine performance data to be retrieved and reconstructed including machine phase information. The system also allows a rule set to be generated from the historical data which is an accurate assessment of these anomalous events. The present invention further provides a system which allows access to the data base at any time so that past learned machine performance can be used. Moreover, the present invention provides a system which, inter alia, provides continuous life time data acquisition for diagnostic and predictive maintenance purposes for maximizing the machines life while minimizing its cost and averting any catastrophic events when in operation.
In one preferred form, the system of the present invention includes a computational means operatively coupled to a sampling means and to at least one machine, for example, to at least one bearing or measurement point to be monitored. The system is adapted to receive signals from a plurality of sensors operatively coupled to the machine. Preferably, the sampling means is operatively coupled to and receives data from at least one
Hala Roger A.
Miguel Joseph D.
Tart Michael Alan
Bently Nevada Corporation
DeBoo Dennis
Wachsman Hal
LandOfFree
Apparatus and method for compressing measurement data... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Apparatus and method for compressing measurement data..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus and method for compressing measurement data... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3026885