Portable, self-contained data collection systems and methods
A portable self-contained data collection system for measuring and collecting vibration data from machines includes an accelerometer which is coupled to the analog input of a data acquisition card. The data acquisition card samples and digitizes the analog signal to produce a time domain digital signal. The data acquisition card output is coupled to a battery-powered portable computer. The battery-powered portable computer includes a database having machine identifications and associated measurement parameters. The portable computer processes the time domain digital signal according to the measurement parameters associated with a selected machine identification, and produces a frequency domain digital signal by performing a Fast Fourier Transform and other digital signal processing operations. The frequency domain signal is also analyzed in the portable computer to produce predictive maintenance information. A power supply for supplying power to the accelerometer is also included. The accelerometer power supply electrically and mechanically couples the accelerometer to the data acquisition card. It supplies power to the accelerometer when the data acquisition card is activated. The portable self-contained data collection system can be used to measure and collect vibration data from machines and to analyze this data to produce predictive maintenance information.
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This application is a continuation of U.S. application Ser. No. 08/526,981, filed Sep. 12, 1995.
FIELD OF THE INVENTIONThis 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 INVENTIONData 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 INVENTIONThe 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, such as a radio frequency (RF) transmitter. However, transmission may also be accomplished by uploading information to another computer using conventional wire communications.
According to another aspect of the present invention, the portable self-contained data collection system also includes a power supply for supplying power to the accelerometer. In particular, conventional portable computers do not provide sufficient power for an accelerometer, which typically requires 24V at 2 mA. According to the invention, an accelerometer power supply electrically and mechanically couples the accelerometer output to the data acquisition card analog input. The accelerometer power supply is preferably responsive to the data acquisition card for supplying power to the accelerometer when the data acquisition card is activated, and for deactivating when the data acquisition card is deactivated.
In particular, the accelerometer power supply includes a power supply housing and an accelerometer battery power supply in the power supply housing which provides sufficient power for an accelerometer. Output means including an output connector electrically and mechanically connects the accelerometer battery power supply to an accelerometer and receives accelerometer signals from the accelerometer. Input means including an input connector electrically and mechanically connects the accelerometer battery power supply to an external device, preferably the analog input of a data acquisition card. The input means receives a control signal from the external device, and also passes the accelerometer signals to the external device. The accelerometer battery power supply is responsive to the control signal, to activate the accelerometer battery power supply to supply battery power for an accelerometer to the output connector. In the absence of the control signal, the accelerometer battery power supply is deactivated. Preferably, the accelerometer battery power supply will pass signals from the output means to the external device in the absence of the control signal, so that non-powered transducers can be used.
When the accelerometer power supply is included, the portable self-contained data collection system includes three hardware components: a portable computer, a data acquisition card and an accelerometer power supply. The portable computer includes a portable computer housing, a portable computer battery power supply within the portable computer housing to supply power to the portable computer, and an expansion slot in the portable computer housing. The data acquisition card is mechanically and electrically coupled to the expansion slot. The accelerometer power supply includes a power supply housing, and an accelerometer battery power supply within the power supply housing which provides sufficient power for an accelerometer. The accelerometer power supply is electrically and mechanically coupled to the data acquisition card and the accelerometer is electrically and mechanically coupled to the accelerometer power supply. The portable computer, data acquisition card and accelerometer power supply may be packaged in a ruggedized carrying case. The portable computer executes software including a database including machine identifications and measurement parameters, signal processing software for processing accelerometer signals and signal analyzing software for analyzing the processed signal to produce predictive maintenance information.
Data collection methods according to the present invention are used for measuring and collecting vibration data from machines, wherein the following steps are all performed in a portable battery-powered computer: A machine identification for measurement is selected. A time domain accelerometer signal is processed according to measurement parameters associated with the selected machine identification to produce a digital signal. The digital signal is analyzed to produce predictive maintenance information. If necessary, the processing step is preceded by the step of sampling and digitizing an analog accelerometer signal to produce the time domain accelerometer signal. The machine identifications, measurements, time domain signal, digital signal and/or predictive maintenance information can be displayed on the portable battery-powered computer. Portable self-contained data collection systems and methods are thereby provided. In addition, this information can be transferred to another computer.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout.
Referring now to
The construction of battery powered portable computer 110 is well-known to those skilled in the art. Battery operated portable computers typically include a microprocessor, associated random access memory (RAM) nonvolatile data storage such as a hard disk drive, a battery power source and expansion slots designed to accommodate circuit boards electrically coupling the computer components to external devices such as keyboards, pens, mouses, transducers and displays. These expansion slots typically accommodate standard form factor circuit cards, such as the industry-standard PCMCIA form factor cards used in notebook and laptop computers. For field uses, such as monitoring of machinery for predictive maintenance purposes, battery operated portable computer 110 may be mounted in a lightweight, rugged hand-held case 101, and user input means 140 may include a magnetic pen designed to operate with a magnetically sensitive screen matrix. An example of a typical battery operated portable computer designed especially for field use is the Fujitsu Stylistic 500, as described in Fujitsu brochure 58-0349-00B, the disclosure of which is incorporated herein by reference. This computer is referred to for purposes of explanation only, and it will be understood by those skilled in the art that the present invention may be used with other portable computers.
Data acquisition card 120 is an analog to digital (A/D) converter card that mechanically and electrically couples data acquisition card 120 to an expansion slot in battery powered portable computer 110, electrically connecting digital output 122 to battery operated portable computer 110. Data acquisition card 120 is electrically coupled to accelerometer 160 at analog input 121. Typically, data acquisition card 120 is a low-cost standard form factor sound card designed to receive audio frequency analog signals at analog input 121. An example of such a sound card is the Magic Ram PCMCIA 16-bit audio adapter, which is described in a manufacturer's data sheet entitled “PCMCIA 16-bit Audio Adapter,” the disclosure of which is incorporated herein by reference. This device is a standard PCMCIA form factor card that mates with a PCMCIA expansion slot. It will be understood by those skilled in the art that a data acquisition card according to the present invention includes any A/D converter card capable of receiving analog inputs and transmitting corresponding digital signals to a battery operated portable computer through a digital communications port, such as an expansion slot. It will also be understood by those skilled in the art that the present invention may be used with a battery operated portable computer 110 which includes an analog input and associated internal A/D.
Accelerometer 160 produces an analog signal corresponding to the accelerations experienced by a motion sensitive transducer included therein, and is electrically coupled to data acquisition card 120 by analog input 121. The motion-sensitive transducer is typically piezoelectric and produces a voltage proportional to the acceleration of the transducer. The accelerometer includes means for coupling the motion sensitive transducer to a machine from which the user desires vibration data, such as a probe extension, screw or magnet attached to the accelerometer structure. Examples of piezoelectric accelerometers may be found in Catalog QSG-200, published by Industrial Monitoring Instrumentation Division of PCB Piezotronics, Inc., the disclosure of which is incorporated herein by reference. It will be understood by those skilled in the art that the present invention may be used with other measurement devices producing analog output signals corresponding to accelerations, such as piezotransistor or variable resistance accelerometers.
Power supply 150 supplies electrical power to accelerometer 160, receives output signals from accelerometer 160, receives control signals from data acquisition card 120, and conveys output signals from accelerometer 160 to data acquisition card 120. Power supply 150 is mechanically and electrically coupled to both accelerometer 160 and data acquisition card 120.
Referring now to
Database 220 comprises a plurality of machine identifications and associated measurement parameters. Database 220 may have a hierarchical, relational or other structure and is typically organized according to logical relationships between particular machines. An example of a hierarchical database structure is incorporated in Entek Scientific Corporation's EMONITOR® for Windows, as described in Chapters 4 and 5 of “EMONITOR® for Windows User's Guide, Second Edition 1994,” Manual No. EEW0002B. This database is a SQL database that organizes machine identifications, and associates parameters such as machine location, signal processing parameters and previously measured data values with these machine identifications. This database is referred to for purposes of explanation, and it will be understood by those skilled in the art that the present invention may be used with other hierarchical or non-hierarchical database structures, and may include various combinations of machine parameters.
Data collection interface 210 is preferably a software module that controls the operation of data acquisition card 120 and signal processing means 230 through operating system 200, although hardware or software/hardware combinations may be employed. Upon commands from data collection interface 210, data acquisition card 120 samples and digitizes an analog signal 115 received from a accelerometer 160 and provides a corresponding time domain digital signal 125, which is conveyed to signal processing means 230. In the embodiment of the present invention shown in
Although the combination of elements described in
Signal processing means 230 performs digital signal processing of time domain digital signal 125 received from data acquisition card 120. Typically, signal processing means 230 is implemented in conventional modular software blocks, which may be selected and combined to perform various processing functions, as further illustrated in
Signal analyzing means 240 typically is software that examines processed digital signals received from signal processing means 230 and produces predictive maintenance information. Upon commands received through operating system 200, signal analyzing means 240 conducts analyses such as trend analysis, alarm detection, spectral analysis, data plotting or report generation. An example of signal analyzing means 240 is the analysis software incorporated in Entek Scientific Corporation's EMONITOR® for Windows, as described in Chapters 7, 9, 10 and 11 of “EMONITOR® for Windows User's Guide, Second Edition 1994,” Manual No. EEW0002B.
Referring now to
Referring now to
Input means 440 electrically and mechanically couples accelerometer battery power supply 420 to an external device, such as an A/D converter, and receives control signal 450 from the external device. Accelerometer battery power supply 420 may be responsive to control signal 450, deactivating power output to the external accelerometer in the absence of control signal 450, thus offering the capability to minimize power consumption during non-measurement periods and extending battery life or time between recharges.
The parameters associated with a particular machine identification typically have been previously entered into a database. This may be done manually, as shown in
In the drawings and specification, there have been disclosed typical preferred embodiments of the invention and, although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention being set forth in the following claims.
Claims
1-17. cancelled
18. A method of collecting machinery maintenance data from machines, comprising:
- providing a portable computer comprising a processor, memory, battery, external interface, and user interface,
- providing an analog machine activity sensor for collecting machinery maintenance data from one or more machines,
- during battery-powered operation of said portable computer, interacting with said processor using said user interface to catalog a machine into said memory by identifying said machine, and identifying machinery measurement parameters to be used with said machine, and
- during battery-powered operation of said portable computer, interacting with said processor using said user interface to select said catalogued machine, and collect data relating to operation of said selected, catalogued machine from said analog machine activity sensor, via said external interface, into said memory of said portable computer, using said machinery measurement parameters.
19. The method of claim 18 wherein said memory comprises dynamic random access memory (DRAM).
20. The method of claim 18 wherein said memory comprises magnetic storage.
21. The method of claim 18 wherein said memory is removable.
22. The method of claim 18 wherein said external interface is a card slot, and an interface card inserted therein, both compatible with a personal computer interface standard permitting removal and replacement of said interface card without restarting operation of said processor.
23. The method of claim 18 further comprising analyzing said data by operating said processor to perform a frequency transformation of said data.
24. The method of claim 18 further comprising providing a sensor power supply for supplying power to said analog machine activity sensor.
25. The method of claim 18 wherein said portable computer further comprises a connector for transmitting information between said memory and a host computer.
26. The method of claim 18 wherein said portable computer further comprises a display.
27. The method of claim 18 wherein said portable computer has less than a full set of alphanumeric keys.
28. The method of claim 18 wherein said analog machine activity sensor is an accelerometer.
29. The method of claim 22 wherein said interface card comprises an analog to digital converter.
30. The method of claim 24 wherein said sensor power supply is responsive to a control signal from said portable computer to activate or deactivate said analog machine activity sensor, and further comprising operating said portable computer to produce a control signal to activate said sensor power supply prior to collecting data from said analog machine activity sensor.
31. The method of claim 24 further comprising providing an interface cord connecting said sensor power supply and said analog machine activity sensor to said portable computer.
32. The method of claim 24 wherein said sensor power supply comprises a sensor power supply battery, and further comprising providing a battery charger and connecting said battery charger to said sensor power supply battery to charge said sensor power supply battery.
33. The method of claim 25 further comprising transmitting at least one of
- data collected from said selected, catalogued machine via said analog machine activity sensor,
- an identification of said selected, catalogued machine, and
- measurement parameters to be used with said selected, catalogued machine
- between said memory and said host computer via said connector.
34. The method of claim 26 further comprising operating said processor to display data collected from said analog machine activity sensor on said display.
35. The method of claim 26 further comprising operating said processor to perform a frequency transformation of data collected from said analog machine activity sensor and display said frequency transformation on said display.
36. The method of claim 27 wherein said portable computer is a pen-based palmtop computer.
37. A computer system for collecting machinery maintenance data from machines, comprising:
- a portable computer comprising a processor, memory, battery, and external interface,
- software in said memory for operating said processor to collect data from an analog machine activity sensor connected to said external interface, and store said data into said memory of said portable computer, and
- sensor power supply circuitry for generating a supply of electrical power for said analog machine activity sensor that is different from that available from said battery.
38. The computer system of claim 37 wherein said memory comprises dynamic random access memory (DRAM).
39. The computer system of claim 37 wherein said memory comprises magnetic storage.
40. The computer system of claim 37 wherein said memory is removable.
41. The computer system of claim 37 wherein said external interface is a card slot, and an interface card inserted therein, both compatible with a personal computer interface standard permitting removal and replacement of said interface card without restarting operation of said processor.
42. The computer system of claim 37 further comprising software in said memory for operating said processor to analyze data collected from said analog machine activity sensor.
43. The computer system of claim 37 further comprising a sensor power supply for supplying power to said analog machine activity sensor.
44. The computer system of claim 37 wherein said sensor power supply is responsive to a control signal from said portable computer to activate or deactivate said analog machine activity sensor, and further comprising software in said memory for operating said portable computer to produce a control signal to activate said sensor power supply prior to collecting data from said analog machine activity sensor.
45. The computer system of claim 37 further comprising an interface cord connecting said sensor power supply and said analog machine activity sensor to said portable computer.
46. The computer system of claim 37 wherein said sensor power supply comprises a sensor power supply battery, and further comprising a battery charger connectable to said sensor power supply battery to charge said sensor power supply battery.
47. The computer system of claim 37 further comprising machine identifications and associated measurement parameters for a plurality of machines stored in said memory.
48. The computer system of claim 37 wherein said portable computer further comprises a display.
49. The computer system of claim 37 wherein said portable computer has less than a full set of alphanumeric keys.
50. The computer system of claim 41 wherein said interface card comprises an analog to digital converter.
51. The computer system of claim 42 wherein said software operates said processor to perform a frequency transformation of said data.
52. The computer system of claim 47 further comprising a connector for transmitting information between said memory and a host computer, including at least one of
- data collected from said analog machine activity sensor,
- an identification of a machine, and
- measurement parameters.
53. The computer system of claim 47 wherein said portable computer further comprises a user interface, and further comprising software in said memory for operating said processor to interact with a user to select a machine identification, and then process data collected from said analog machine activity sensor in accordance with measurement parameters associated with said selected machine identification.
54. The computer system of claim 48 further comprising software in said memory for operating said processor to display data collected from said analog machine activity sensor on said display.
55. The computer system of claim 48 further comprising software in said memory for operating said processor to perform a frequency transformation of data collected from said analog machine activity sensor and display said frequency transformation on said display.
56. The computer system of claim 49 wherein said portable computer is a pen-based palmtop computer.
57. A computer system for collecting machinery maintenance data from machines, comprising:
- a portable computer comprising a processor, memory, battery, external interface, and user interface, said user interface having less than a full set of alphanumeric keys,
- software in said memory for interacting with a user via said user interface to catalog a machine into said memory by identifying said machine, and identifying machinery measurement parameters to be used with said machine,
- software in said memory for operating said processor to collect data from an analog machine activity sensor connected to said external interface, and store said data into said memory of said portable computer.
58. The computer system of claim 57 wherein said memory comprises dynamic random access memory (DRAM).
59. The computer system of claim 57 wherein said memory comprises magnetic storage.
60. The computer system of claim 57 wherein said memory is removable.
61. The computer system of claim 57 wherein said external interface is a card slot, and an interface card inserted therein, both compatible with a personal computer interface standard permitting removal and replacement of said interface card without restarting operation of said processor.
62. The computer system of claim 57 further comprising software in said memory for operating said processor to analyze data collected from said analog machine activity sensor.
63. The computer system of claim 57 further comprising a sensor power supply for supplying power to said analog machine activity sensor.
64. The computer system of claim 57 further comprising machine identifications and associated measurement parameters for a plurality of machines stored in said memory.
65. The computer system of claim 57 wherein said portable computer further comprises a display.
66. The computer system of claim 57 wherein said portable computer is a pen-based palmtop computer.
67. The computer system of claim 61 wherein said interface card comprises an analog to digital converter.
68. The computer system of claim 62 wherein said software operates said processor to perform a frequency transformation of said data.
69. The computer system of claim 63 wherein said sensor power supply is responsive to a control signal from said portable computer to activate or deactivate said analog machine activity sensor, and further comprising software in said memory for operating said portable computer to produce a control signal to activate said sensor power supply prior to collecting data from said analog machine activity sensor.
70. The computer system of claim 63 further comprising an interface cord connecting said sensor power supply and said analog machine activity sensor to said portable computer.
71. The computer system of claim 63 wherein said sensor power supply comprises a sensor power supply battery, and further comprising a battery charger connectable to said sensor power supply battery to charge said sensor power supply battery.
72. The computer system of claim 64 further comprising a connector for transmitting information between said memory and a host computer, including at least one of
- data collected from said analog machine activity sensor,
- an identification of a machine, and
- measurement parameters.
73. The computer system of claim 64 further comprising software in said memory for operating said processor to interact with a user to select a machine identification, and then process data collected from said analog machine activity sensor in accordance with measurement parameters associated with said selected machine identification.
74. The computer system of claim 65 further comprising software in said memory for operating said processor to display data collected from said analog machine activity sensor on said display.
75. The computer system of claim 65 further comprising software in said memory for operating said processor to perform a frequency transformation of data collected from said analog machine activity sensor and display said frequency transformation on said display.
Type: Application
Filed: Oct 1, 2004
Publication Date: Mar 17, 2005
Applicant: Entek IRD International Corporation (Milford, OH)
Inventors: Richard Schiltz (Hamilton, OH), Andrew Bates (Somerset), Jeffery Watkins (Cincinnati, OH)
Application Number: 10/957,245