Data encodement and reading method and apparatus

• US 5,202,682 A
• Filed: 10/18/1991
• Issued: 04/13/1993
• Est. Priority Date: 07/13/1989
• Status: Expired due to Fees

• Current Assignee: Curtis Instruments Incorporated
• Original Assignee: Curtis Instruments Incorporated
• Inventors: Finger, Eugene P.
• Primary Examiner(s): Yusko, Donald J.
• Assistant Examiner(s): Horabik, Michael
• Application Number:
  US07/780,409
• Time in Patent Office: 543 Days
• Field of Search: 340/870.04, 340/870.09, 340/870.19, 340/870.24, 340/870.25, 340/870.27, 340/825.63, 340/825.57, 341/178, 341/180, 341/182, 370/41, 375/22, 375/23, 375/24, 377/16, 377/20, 377/25, 324/77 R, 324/99 D, 324/118
• US Class Current: 340/870.19
• CPC Class Codes: G01R 15/125 for digital multimeters
• CPC Class Codes: G01R 19/25 using digital measurement techniques
• CPC Class Codes: G07C 3/04 using counting means or digital clocks

Abstract

A method and apparatus for measuring operations data which uses a commercially available digital multimeter (DMM) as the data receiving and display device. In one preferred embodiment, for example, basic operations data is transduced to digital form and then coded with a width modulator. The width modulated data may represent, for example, total elapsed time or total counts of a measured operation. The full-scale range of the data is encoded as frequency. A technician reads the frequency of the data signal with the DMM to determine the full-scale range of the data and then reads percent-of-range with the DMM as duty cycle. For multiple operations data, peak voltage is used as a parameter identifier. Alternatively, the value of the parameter being measured, the full-scale range, and the parameter identifier may be encoded as any combination of frequency, peak voltage, or duty cycle. In a further aspect, one parameter, preferably frequency, may be encoded with additional information, such as data site and data channel. In another aspect, the data stream is amplitude modulated to indicate selected alarm levels.

Claims

1. A method of processing and reading a single data signal having a value and representing a parameter, comprising:

(a) electronically encoding said single data signal with a first variable indicating full-scale range of said value;

(b) electronically encoding said single data signal with a second variable indicating the magnitude of said value;

(c) reading said first variable in said single data signal to determine said full-scale range; and

(d) reading said second variable in said single data signal to determine said value.

2. A method, as defined in claim 1, further including the steps of:

(e) electronically encoding said single data signal with a third variable indicating said parameter said data represents; and

(f) reading said third variable in said single data signal to determine said parameter said data represents.

3. A method, as defined in claim 1, wherein said first and second variables are selected from the group consisting of frequency, peak voltage, and duty cycle.

4. A method, as defined in claim 2, wherein said variables are two or more variables selected from the group consisting of frequency, peak voltage, and duty cycle.

5. A method, as defined in claim 1, wherein said variables are read with a digital multimeter.

6. A method, as defined in claim 3, further comprising means to encode said single data signal with a variable indicating an alarm level.

7. An apparatus for processing and reading a single data signal having a value and representing a parameter, comprising:

(a) means for electronically encoding said single data signal with a first variable indicating full-scale range of said value;

(b) means for electronically encoding said single data signal with a second variable indicating the magnitude of said value;

(c) means for reading said first variable in said single data signal to determine said full-scale range; and

(d) means for reading said second variable in said single data signal to determine said value of said data.

8. An apparatus, as defined in claim 7, further comprising:

(e) means for electronically encoding said single data signal with a third variable indicating said parameter said data represents; and

(f) means for reading said third variable in said single data signal to determine said parameter said data represents.

9. An apparatus, as defined in claim 7, wherein said first and second variables are selected from the group consisting of frequency, peak voltage, and duty cycle.

10. An apparatus, as defined in claim 8, wherein said variables are two or more variables selected from the group consisting of frequency, peak voltage, and duty cycle.

11. An apparatus, as defined in claim 7, wherein said means for reading comprises a digital multimeter.

12. An apparatus, as defined in claim 10, further comprising:

(a) means for electronically encoding said single data signal with a variable selected from said group indicating an alarm condition; and

(b) means for reading said variable in said single data signal to determine if said alarm condition exists.

13. An apparatus for processing and reading single data signals indicating values of a plurality of parameters, comprising:

(a) a plurality of encoding means each one for connection to one of a plurality of devices each one containing one of said single data signals indicating the value of one of said parameters, each of said encoding means to receive and encode one of said single data signals with a first variable uniquely indicating the full-scale range of said value, to encode said single data signal with a second variable uniquely indicating the parameter represented by said first variable, and to encode said single data signal with a third variable the magnitude of which indicates the magnitude of said value of said parameter;

(b) connection means to connect said apparatus to the inputs of a digital multimeter;

(c) means to short-circuit said connection means a selected length of time during which no signal can be detected across said connection means;

(d) counter and decoder means to sequentially select one of said encoding means to provide one of said single data signals to said connection means;

(e) missing pulse means to detect when said connection means is shorted; and

(f) single shot circuit means responsive to said missing pulse means to cause said counter and decoder means to increment when said connection means is short-circuited.

14. An apparatus, as defined in claim 13, wherein said variables are two or more variables selected from the group consisting of frequency, peak voltage, and duty cycle.

15. An apparatus, as defined in claim 14, further comprising means to encode said single data signal with a variable indicating an alarm level.

16. An apparatus, as defined in claim 13, further comprising:

(a) reset circuit means connected to at least one of said plurality of devices for resetting thereof, said circuit means having input means to selectively provide logical "1" or logical "0" inputs, a selected output from which reset circuit means causes said at least one of said plurality of devices to rest; and

(b) said input means to selectively provide either a logical "1" input or a logical "0" input for a first selected period of time, at the end of which said first selected period of time, said reset circuit means provides said selected output.

17. An apparatus, as defined in claim 16, wherein said reset circuit means provides said selected output only after termination of the other of said logical "1" or "0" inputs for a second selected period of time following said first selected period of time.

18. An apparatus for processing and reading single data signals indicating values of a plurality of parameters, comprising:

(a) a plurality of encoding means each one for connection to one of a plurality of devices each one containing one of said single data signals indicating the value of one of said parameters, each of said encoding means to encode each one of said single data signals with a first variable uniquely indicating the full-scale range of said value and to encode said single data signal with a second variable the magnitude of which said second variable indicates the magnitude of said value of said parameter;

(b) means to provide for each parameter an identifying third variable indicating the identity of said parameter;

(c) connection means to connect said apparatus to the inputs of a digital multimeter;

(d) means to short-circuit said connection means a selected length of time during which no signal can be detected across said connection means;

(e) counter and decoder means to sequentially select one of said encoding means to provide one of said single data signals to said connection means;

(f) switch means to selectively provide to said connection means either one of said single data signals or the said identifying variable unique to said one of said single data signals;

(g) missing pulse means to detect when said connection means is shorted; and

(h) single shot circuit means responsive to said missing pulse means to cause said counter and decoder means to increment when said connection means is shorted, to cause said switch means to provide to said connection means said identifying third variable unique to said one of said single data signals for a selected interval of time, then to cause said switch means to provide to said connection means said first variable indicating the full-scale range of said value.

19. An apparatus, as defined in claim 18, wherein said variables are two or more variables selected from the group consisting of frequency, peak voltage, and duty cycle.

20. An apparatus, as defined in claim 19, further comprising means to encode said single data signal with a variable indicating an alarm level.

21. An apparatus, as defined in claim 18, further comprising:

(a) reset circuit means connected to at least one of said plurality of devices for resetting thereof, said circuit means having input means to selectively provide logical "1" or logical "0" inputs, a selected output from which reset circuit means causes said at least one of said plurality of devices to reset; and

(b) said input means to selectively provide either a logical "1" input or a logical "0" input for a first selected period of time, at the end of which said first selected period of time, said reset circuit means provides said selected output.

22. An apparatus, as defined in claim 21, wherein said reset circuit means provides said selected output only after termination of the other of said logical "1" or "0" inputs for a second selected period of time following said first selected period of time.

23. A method of processing and reading single data signals indicating values of a plurality of parameters, comprising:

(a) encoding each one of said single data signals with a first variable uniquely indicating the full-scale range of said value, encoding each of said single data signals with a second variable uniquely indicating the parameter represented by said first variable, and encoding each of said single data signals with a third variable the magnitude of which said third variable indicates the magnitude of said value of said parameter;

(b) sequentially selecting one of said encoded single data signals;

(c) using a digital multimeter to read said second variable indicating said parameter;

(d) using said digital multimeter to read said first variable indicating said full-scale range; and

(e) using said digital multimeter to read said third variable indicating the magnitude of said value of said parameter.

24. A method, as defined in claim 23, wherein said variables are two or more variables selected from the group consisting of frequency, peak voltage, and duty cycle.

25. A method, as defined in claim 24, further comprising means to encode said single data signal with a variable indicating an alarm level.

26. A method of processing and reading single data signals indicating values of a plurality of parameters, comprising:

(a) encoding each one of said signal data signals with a first variable uniquely indicating the full-scale range of said value, encoding each one of said single data signals with a second variable the magnitude of which said second variable indicates the magnitude of said value;

(b) providing for each parameter an identifying third variable indicating the identity of said parameter;

(c) sequentially selecting one of said encoded single data signals;

(d) using a digital multimeter to read said third variable indicating the identity of said parameter;

(e) using said digital multimeter to read said first variable to indicate the full-scale range of said value; and

(f) using said digital multimeter to read said second variable to indicate the magnitude of said value.

27. A method, as defined in claim 26, wherein said variables are two or more variables selected from the group consisting of frequency, peak voltage, and duty cycle.

28. A method, as defined in claim 27, further comprising means to encode said single data signal with a variable indicating an alarm level.