Portable data collector and analyzer: apparatus and method

• US 6,789,030 B1
• Filed: 06/23/2000
• Issued: 09/07/2004
• Est. Priority Date: 06/23/2000
• Status: Expired due to Fees

• Current Assignee: BN Corporation LLC
• Original Assignee: Bently Nevada Incorporated (General Electric Company)
• Inventors: Barnes, Andrew, Coyle, Sean, Doggett, Anthony, Wood, Dean, Dagnall, Christopher
• Primary Examiner(s): Hoff, Marc S.
• Assistant Examiner(s): Raymond, Edward
• Application Number:
  US09/603,659
• Time in Patent Office: 1,537 Days
• Field of Search: 702/77, 702/190, 702/189, 702/113, 702/141, 702/179, 702/182, 702/76
• US Class Current: 702/77
• CPC Class Codes: G01D 9/005 Solid-state data loggers

Abstract

A portable data collector and analyzer apparatus and method provides predictive and preventative maintenance of a multiplicity of assets through the use of a unique architecture that allows a variety of different application programs to be downloaded to the apparatus for providing a single multi-purpose portable data collector and analyzer apparatus that can employ the variety of different application programs for configuring, inter alia, different measurements types, different transducers types and different signal processing types for collecting and analyzing sensed physical data from a variety of different assets found in industrial plants. A unique frequency shifting and decimation method is employed for spectrum calculation that, inter alia, retains DSP addressing efficiency and increases signal processing speed. Additionally, a unique synchronous sampling method is employed that generates synchronous sample waveforms from asynchronous sample waveforms. Furthermore, a unique clear touch screen overlying a quarter VGA display, an ergonomically designed keypad, and an intuitive user interface allow quick and easy setup and operation for in-field data acquisition, analysis and display.

Claims

1. A portable data collector and analyzer apparatus, comprising in combination:

a transducer for sensing dynamic data and producing analog signals correlative to said sensed data;

signal conditioning circuitry operatively coupled to said transducer for receiving and conditioning said analog signals from said transducer to produce conditioned analog signals;

a filter circuit operatively coupled to said signal conditioning circuitry for receiving and filtering said conditioned analog signals to produce filtered analog signals;

an analog to digital converter circuit operatively coupled to said filter circuit for receiving and sampling said filtered analog signals to produce digital data samples;

a digital signal processor operatively coupled to said analog to digital converter circuit for receiving and operating on said digital data samples for selecting N samples wherein N is an integer power of two,

said digital signal processor operating on said N samples by frequency shifting said N samples a predetermined amount to produce a set of N complex samples,

said digital signal processor performing at least one decimation on said N complex samples for defining X number of packets of complex samples each comprised of N/X number of complex samples wherein X has an initial value of two for said at least one decimation and wherein X increases thereafter by a multiple of two for each subsequent decimation until a final predetermined number of decimations of said N complex samples is performed for defining a final number of packets of complex samples;

said digital signal processor performing a Fast Fourier Transform on said final number of packets of complex samples for producing frequency spectrum data;

a microprocessor device and;

an external shared memory device interfaced between and shared by both said digital signal processor device and said microprocessor device for receiving and storing said frequency spectrum data from said digital signal processor and transferring said stored frequency spectrum data to said microprocessor device.

2. The apparatus of claim 1 wherein said digital signal processor repeatedly performs said decimation on said N complex samples until a final number of 1024 packets of complex samples is obtained wherein each of said 1024 packets include two complex samples.

3. The apparatus of claim 2 wherein said digital signal processor performs a radix two complex Fast Fourier Transform on said final number of 1024 packets.

4. The apparatus of claim 3 wherein said digital signal processor frequency shifts said N samples by said predetermined amount being determined by the formula:

5. A method for processing data with a portable data collector and analyzer apparatus, said method including the steps of:

(a) sensing dynamic data and producing analog signals correlative to said sensed data;

(b) converting said signals into digital data samples;

(c) defining a resolution of lines of a final output line spectrum;

(d) selecting N digital data samples wherein N is an integer power of two,

(e) frequency shifting said N digital data samples by a predetermined frequency amount to produce a set of N point complex data,

(f) decimating said N point complex data for defining X number of decimated points wherein X is an integer,

(g) performing a Fast Fourier Transform on said X number of decimated points for producing a line spectrum;

(g) storing said line spectrum into a memory device, and

(h) iteratively repeating steps (e) through (g) for a predetermined integer number of times until said defined resolution of lines of said final output line spectrum is obtained.

6. The method of claim 5 wherein said frequency shifting step includes frequency shifting said N digital data samples by a predetermined frequency amount determined by the formula:

7. The method of claim 6 wherein said decimation step includes decimating said N point complex data for defining 1024 decimated points.

8. The method of claim 7 wherein said step of performing said Fast Fourier Transform on said X number of decimated points for producing said line spectrum includes performing a radix two complex Fast Fourier Transform on said 1024 decimated points for producing said line spectrum.

9. A method for processing data with a portable data collector and analyzer apparatus, said method including the steps of:

(a) determining a start time of a packet of data having a predetermined number of asynchronous samples contained therein;

(b) determining a first trigger time which is later than the determined start time of the packet;

(c) determining a subsequent trigger time which is consecutive to the first trigger time and which is earlier than the determined end time of the packet;

(d) calculating a synchronous sample period by dividing the time between the consecutive trigger pulses by a predetermined synchronous sample rate;

(e) determining a first asynchronous sample that is prior to and closest the first trigger pulse and determining a second asynchronous sample consecutive to the first determined asynchronous sample;

(f) interpolating between the first and the second asynchronous samples for generating a value of a first synchronous sample at the first trigger pulse time,

(g) determining a subsequent synchronous sample time by adding the synchronous sample period to the first trigger pulse time,

(h) determining two asynchronous samples, one sample just before and one sample just after the subsequent synchronous sample time;

(i) interpolating between the two asynchronous samples for generating and storing a value of a subsequent synchronous sample at the subsequent synchronous sample time,

(j) determining a next subsequent synchronous sample time by adding the synchronous sample period to the last subsequent synchronous sample time,

(k) skipping to step (o) if the next subsequent synchronous sample time is after the time of the next trigger pulse;

(l) determining two asynchronous samples, one sample just before and one sample just after the next subsequent synchronous sample time;

(m) interpolating between the two asynchronous samples for generating a value for a next subsequent synchronous sample at the next subsequent synchronous sample time;

(n) iteratively repeating steps (j) through (m);

(o) iteratively repeating steps (j) through (m) if the time of the next trigger pulse is before the end of the asynchronous buffer and replacing the step (k) next trigger pulse value with a next trigger pulse value consecutive to the next trigger pulse value in step (k);

(p) storing the generated synchronous samples as a synchronous sample waveform if the next trigger pulse value in step (k) is after the end of the asynchronous buffer.

10. The method of claim 9 further including the step of processing subsequent buffers of asynchronous samples by iteratively repeating steps (a) through (p) above and by replacing the buffer start time with a next subsequent synchronous sample time that is after the last subsequent synchronous sample time used to generate the last synchronous sample of the last synchronous sample waveform generated from the last buffer.