Hand held data collector and analyzer system

• US 5,870,699 A
• Filed: 02/25/1997
• Issued: 02/09/1999
• Est. Priority Date: 12/09/1994
• Status: Expired due to Term

• Current Assignee: Computational Systems Incorporated (Emerson Electric Company)
• Original Assignee: CSI Technology Incorporated (Emerson Electric Company)
• Inventors: Nelson, Thomas E., Simpson, Danny, Czyzewski, Zbigniew, Canada, Ronald G.
• Primary Examiner(s): Barlow, John
• Assistant Examiner(s): ASSOUAD, PATRICK J
• Application Number:
  US08/810,132
• Time in Patent Office: 714 Days
• Field of Search: 364/576, 364/484-487, 364/508, 364/572, 364/574, 324/76.19, 324/76.21, 324/76.28, 702/190, 702/189, 702/113, 702/141, 702/179, 702/187, 702/182
• US Class Current: 702/190
• CPC Class Codes: G01H 1/00 Measuring characteristics of vibrations in solids by using direct conduction to the detector G01H9/00, G01H11/00 take precedence
• CPC Class Codes: G01H 1/14 Frequency

Abstract

A hand held data collector and analyzer achieves superior stability, accuracy and reliability through the use of a fixed frequency anti-aliasing filter and two analog to digital converters, one for high frequency signals and one for low frequency signals. Efficient digital filtering and decimation is achieved by providing specialized hardware filters and decimators and implementing software filters and decimators in a data processor. A true zoom method is employed to take advantage of the filtering and decimation capabilities, and independent digital signal processors operate serially on incoming signals to further reduce demands on the central processing unit. In addition, the RAM system memory is formatted as a pseudo-card to facilitate use of a PCMCIA memory card or the RAM system memory.

Claims

1. A data collector and analyzer system comprising:

a vibration transducer for sensing vibration and for producing an analog vibration signal corresponding to the vibration;

a conditioning circuit for receiving and conditioning the analog vibration signal from the vibration transducer to produce a conditioned analog signal, and having;

(a) a filter for producing the conditioned analog signal having a desired frequency range;

(b) an amplifier for producing the conditioned analog signal at a desired amplitude;

(c) an analog to digital converter (ADC) for receiving and sampling the conditioned analog signal to produce a digital signal;

a data processor for processing the digital signal to produce desired digital data, the data processor including;

a transformer for selectively operating on the digital signal, performing a Fast Fourier Transform, and producing frequency spectrum data from the digital signal;

a digital signal processor (DSP) connected to receive and for operating on the digital signal and independently performing Fast Fourier Transforms on the digital signal to produce a frequency spectrum; and

a central processing unit (CPU) for controlling the operation of the system including the operation of the DSP, the DSP performing the Fast Fourier Transform independently of the CPU;

memory interfaced with the data processor for storing at least some of the digital data;

the DSP for generating a graphical representation of the frequency spectrum, and transferring the graphical representation to the memory; and

a direct memory access (DMA) for transferring data directly to the memory without interrupting the CPU, the DMA transferring data including the frequency spectrum and the graphical representation from the DSP to the memory.

2. The system of claim 1 wherein the DSP performs a true zoom operation on the digital signal to produce a zoom digital signal representative of a selected frequency band in the digital signal.

3. The system of claim 1 wherein the DSP in response to commands from the CPU performs a low-pass filtering and decimation operation on the digital signal independently of the CPU to produce a filtered digital signal having a reduced sample rate as compared to the digital signal and being representative of a portion of the digital signal having a frequency below a selected upper frequency.

4. The system of claim 1 wherein the DSP in response to commands from the CPU performs:

a low-pass filtering and decimation operation on the digital signal independently of the CPU to produce a filtered digital signal having a reduced sample rate as compared to the digital signal and being representative of a portion of the digital signal having a frequency below a selected upper frequency;

a zoom operation independently of the CPU signal to produce a zoom digital signal representative of a selected frequency band in the digital signal; and

a Fast Fourier Transform independently of the CPU to produce a frequency spectrum representative of a frequency content of the digital signal.

5. A data collector and analyzer system comprising:

a vibration transducer for sensing vibration and for producing an analog vibration signal corresponding to the vibration;

a conditioning circuit for receiving and conditioning the analog vibration signal from the vibration transducer to produce a conditioned analog signal, and having;

(a) a filter for producing the conditioned analog signal having a desired frequency range;

(b) an amplifier for producing the conditioned analog signal at a desired amplitude;

(c) an analog to digital converter (ADC) for receiving and sampling the conditioned analog signal to produce a digital signal;

a data processor for processing the digital signal to produce desired digital data, the data processor including;

a transformer for selectively operating on the digital signal, performing a Fast Fourier Transform, and producing frequency spectrum data from the digital signal;

a digital signal processor (DSP) connected to receive and for operating on the digital signal and independently performing Fast Fourier Transforms on the digital signal to produce a frequency spectrum; and

a central processing unit (CPU) for controlling the operation of the system including the operation of the DSP, the DSP performing the Fast Fourier Transform independently of the CPU;

memory interfaced with the data processor for storing at least some of the digital data;

a memory card for storing data in a card format;

a plug system for connecting and disconnecting the memory card to and from the system;

a random access memory (RAM) interfaced with the data processor for storing data; and

a RAM formatter for controlling the flow of data to and from the RAM and configuring the RAM as a pseudo-card so that the RAM in conjunction with the RAM formatter functions substantially identically as the memory card, receiving and transmitting data in card format.

6. The system of claim 5 wherein the data processor further comprises a digital filter for optionally digitally filtering the digital signal to produce a modified digital signal.

7. The system of claim 5 wherein the data processor further comprises a digital filter and decimator for optionally reducing the sample rate and frequency content of the digital signal to produce a modified digital signal.

8. A data collector and analyzer system comprising:

a vibration transducer for sensing vibration and for producing an analog vibration signal corresponding to the vibration;

a conditioning circuit for receiving and conditioning the analog vibration signal from the vibration transducer to produce a conditioned analog signal, and having;

(a) a filter for producing the conditioned analog signal having a desired frequency range;

(b) an amplifier for producing the conditioned analog signal at a desired amplitude; and

(c) an analog to digital converter (ADC) for receiving and sampling the conditioned analog signal to produce a digital signal, and having;

(1) a sigma-delta modulator having a number of cascaded sigma-delta loops and having a transfer function substantially of;

space="preserve" listing-type="equation">(z)=X(z)+(1-Z.sup.-1).sup.-n Q.sup.n (Z)

where Qⁿ is the quantization noise from the sigma-delta modulator and n is the number of cascaded sigma-delta loops, the modulator receiving the conditioned analog signal and producing a digital modulator signal;

(2) a filter for digitally low-pass filtering and decimating the digital modulator signal to produce the digital signal for the data processor;

a data processor for processing the digital signal to produce desired digital data, the data processor including;

a transformer for selectively operating on the digital signal, performing a Fast Fourier Transform, and producing frequency spectrum data from the digital signal; and

memory interfaced with the data processor for storing at least some of the digital data.

9. A data collector and analyzer system comprising:

a vibration transducer for sensing vibration and for producing an analog vibration signal corresponding to the vibration;

a conditioning circuit for receiving and conditioning the analog vibration signal from the vibration transducer, and having;

a main conditioning circuit for receiving and conditioning the analog signal from the transducer to produce a conditioned main analog signal, and having;

(a) a filter having an upper cutoff frequency for producing the conditioned main analog signal having a desired frequency range;

(b) an amplifier for producing the conditioned main analog signal at a desired amplitude;

(c) a main analog to digital converter (ADC) for receiving and sampling the conditioned main analog signal to produce a main digital signal; and

(d) a main microprocessor controller for controlling the main conditioning circuit; and

an optional conditioning circuit for receiving and conditioning the analog signal from the transducer to produce a conditioned optional analog signal, and having;

(a) a filter having an upper cutoff frequency for producing the conditioned optional analog signal having a desired frequency range;

(b) an amplifier for producing the conditioned optional analog signal at a desired amplitude; and

(c) an optional ADC for receiving and sampling the conditioned optional analog signal to produce an optional digital signal;

a data processor for processing the main and optional digital signals to produce desired digital data, the data processor including;

a main transformer for selectively operating on the main digital signal, performing a Fourier Transform, and producing frequency spectrum data from the main digital signal; and

an optional transformer for selectively operating on the optional digital signal simultaneously with the main transformer operation, performing a Fourier Transform, and producing frequency spectrum data from the optional digital signal; and

memory interfaced with the data processor for storing at least some of the digital data.

10. The system of claim 9 wherein the main and optional conditioning circuits further comprise main and optional hardware for receiving and sampling the conditioned main analog signal and the conditioned optional analog signal, respectively, at sample frequencies that are substantially greater than maximum frequencies of interest to produce main and optional digital signals, and further for digitally low-pass filtering and digitally decimating the main and optional digital signals, respectively, to produce main and optional conditioned digital signals having reduced sample rates as compared to the main and optional digital signals, respectively, and having predetermined upper cutoff frequencies.

17. The system of claim 9 further comprising:

a main circuit board for mounting the main conditioning circuit and the main transformer and being electrically connected to the system;

an optional circuit board for mounting the optional conditioning circuit and the optional transformer;

plug means for selectively connecting and disconnecting the optional circuit board to and from the system.

11. A hand held data collector and analyzer system comprising:

a main transducer for sensing analog data and for producing a main analog signal corresponding to the analog data;

an optional transducer for sensing analog data and for producing an optional analog signal corresponding to the analog data;

a main conditioning circuit for receiving and conditioning the main analog signal from the main transducer to produce a conditioned main analog signal, and having;

(a) a filter having an upper cutoff frequency for producing the conditioned main analog signal having a desired frequency range;

(b) an amplifier for producing the conditioned main analog signal at a desired amplitude;

(c) a main analog to digital converter (ADC) for receiving and sampling the conditioned main analog signal to produce a main digital signal; and

(d) a main microprocessor controller for controlling the main conditioning circuit;

an optional conditioning circuit for receiving and conditioning the optional analog signal from the optional transducer to produce a conditioned optional analog signal, and having;

(a) a filter having an upper cutoff frequency for producing the conditioned optional analog signal having a desired frequency range;

(b) an amplifier for producing the conditioned optional analog signal at a desired amplitude; and

(c) an optional ADC for receiving and sampling the conditioned optional analog signal to produce an optional digital signal;

a main digital signal processor (DSP) for receiving and selectively operating on the main digital signal, performing a Fast Fourier Transform, and producing a main frequency spectrum;

an optional DSP for receiving and selectively operating on the optional digital signal, performing a Fast Fourier Transform, and producing an optional frequency spectrum;

a central processing unit (CPU) for controlling the operation of the system, including issuing commands to the optional DSP and the main microprocessor controller;

a main interface for connecting the CPU to the main DSP and the main microprocessor controller;

an optional interface for connecting the CPU to the optional DSP;

the main microprocessor controller for controlling the main conditioning circuit in response to commands from the CPU;

the optional DSP for controlling the optional conditioning circuit in response to commands from the CPU; and

memory interfaced with the CPU and the main and optional DSP'"'"'s for storing information.

12. The system of claim 11 wherein:

the main and optional conditioning circuits further comprise main and optional hardware for receiving and sampling the conditioned main analog signal and the conditioned optional analog signal, respectively, at sample frequencies that are substantially greater than maximum frequencies of interest to produce main and optional digital signals, and further for digitally low-pass filtering and digitally decimating the main and optional digital signals, respectively, to produce main and optional conditioned digital signals having reduced sample rates as compared to the main and optional digital signals, respectively, and having predetermined upper cutoff frequencies; and

the main and optional DSP'"'"'s further comprising main and optional digital low-pass filters and decimators, respectively, for optionally and selectively reducing the sample rates and frequency content of the main and optional conditioned digital signals to produce main and optional modified conditioned digital signals.

13. The system of claim 11 wherein the main DSP and the optional DSP, in response to commands from the CPU, perform:

a low-pass filtering and decimation operation independently of the CPU to produce main and optional filtered digital signals, respectively, having reduced sample rates as compared to the main and optional digital signals, respectively, and being representative of a portion of the main and optional digital signals;

a zoom operation independently of the CPU to produce main and optional zoom digital signals, respectively, representative of selected frequency bands in the main and optional digital signals; and

a Fast Fourier Transform independently of the CPU to produce frequency spectrums representative of a frequency content of the main and optional digital signals.

14. The system of claim 11 wherein the optional conditioning circuit further comprises:

a separate optional circuit board; and

plug means for selectively connecting and disconnecting the optional circuit board to and from the system.

15. The system of claim 11 wherein:

the main and optional DSP'"'"'s operate on and analyze the main and optional digital signals independently of the CPU to produce main and optional analyzed digital signals representing selected properties of the main and optional digital signals, and transmit the analyzed digital signals to the memory independently of the CPU; and

the CPU includes a direct memory access (DMA) interconnected with the main and optional DSP'"'"'s and with the memory for transferring data from the main and optional DSP'"'"'s to the memory without interrupting the CPU.

16. The system of claim 11 wherein the filter further comprises a fixed-frequency analog anti-aliasing filter.

18. A multichannel data collector and analyzer system capable of receiving and analyzing signals from transducers including vibration transducers comprising:

multichannel conditioning circuitry for receiving and conditioning the analog vibration signals from the transducers to produce conditioned analog signals, and having;

(a) filters for producing the conditioned analog signals having desired frequency ranges;

(b) an amplifier for operating on an analog signal at a desired gain for producing a conditioned analog signal at a desired amplitude;

(c) analog to digital converter means for receiving and sampling the conditioned analog signals to produce digital signals;

first and second digital signal processors (DSPs) connected to receive the digital signals for independently and simultaneously operating on the digital signals and analyzing the digital signals to produce digital data based on the digital signals, and

memory interfaced with the data processor for storing the digital data.

19. The system of claim 18 wherein said analog to digital converter means further comprise:

a first ADC for receiving and sampling a conditioned analog signal at a relatively high sample rate to produce a first digital signal;

a second ADC for receiving and sampling a conditioned analog signal at a relatively low sample rate to produce a second digital signal; and

said data processor selectively receiving at least one of said first and second digital signals.

20. A hand held vibration monitoring system for collecting, analyzing, and storing vibration data, comprising:

transducer means for sensing vibration and for producing at least one analog vibration signal corresponding to the vibration;

conditioning circuit means;

(a) for receiving and conditioning the analog vibration signal from the vibration transducer to produce at least one conditioned analog signal;

(b) including at least one amplifier and at least one anti-aliasing filter having an upper cutoff frequency set at a desired frequency for operating on the analog vibration signal and for producing at least one conditioned analog signal having a desired frequency content;

(c) including a first analog to digital converter (ADC) for receiving and sampling at least one conditioned analog signal at a relatively high sample rate to produce a first digital signal; and

(d) a second ADC for receiving and sampling at least one conditioned analog signal at a relatively low sample rate to produce a second digital signal;

a data processor for receiving and digitally processing the first and second digital signals to produce desired digital data and for storing data based on the desired digital data;

a user input interfaced with said data processor for inputting commands and data to said data processor;

a display interfaced with said data processor for displaying information to the user;

memory interfaced with the data processor for storing information including the data; and

means for transferring information that is stored in said memory to the computer.

21. The system of claim 20 wherein said data processor performs a true zoom operation on at least one of the digital signals to produce a zoom digital signal representative of a related frequency band in at least one of the digital signals.

22. The system of claim 20 wherein said data processor performs a true zoom operation on at least one of the digital signals to produce a zoom frequency spectrum representative of a selected frequency band in at least one of the digital signals.

23. The system of claim 20 wherein said data processor further comprises at least two microprocessors, each microprocessor being connected to receive a digital signal corresponding to the vibration and being configured to operate on the digital signal independently of and simultaneously with operation of the other processor on a digital signal corresponding to vibration.