CN1052951A - The automatic range selector of digital multimeter measuring instrument - Google Patents
The automatic range selector of digital multimeter measuring instrument Download PDFInfo
- Publication number
- CN1052951A CN1052951A CN90108459A CN90108459A CN1052951A CN 1052951 A CN1052951 A CN 1052951A CN 90108459 A CN90108459 A CN 90108459A CN 90108459 A CN90108459 A CN 90108459A CN 1052951 A CN1052951 A CN 1052951A
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- China
- Prior art keywords
- converter
- attenuator
- voltage
- range
- digital
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R15/00—Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00, G01R33/00 - G01R33/26 or G01R35/00
- G01R15/08—Circuits for altering the measuring range
- G01R15/09—Autoranging circuits
Abstract
The range autoselector of digital multimeter measuring instrument comprises the damping characteristic device of the tested voltage of decaying; The output signal of attenuator is converted to the A/D converter of digital signal; The counter that the output signal of A/D converter is counted; Produce the parallel A/D converter of Parallel Digital output, it comprises the resistance that produces reference voltage, comparer that the attenuator output voltage is compared with reference voltage and the scrambler of linking comparer, and according to the steering logic and the range selector of the output voltage of the output signal control attenuator of parallel A/D converter.Measured value required for the present invention once just can directly be produced by the A/D converter conversion, so Measuring Time is extremely short.
Description
The present invention relates to be used for the digital multimeter measuring instrument of measuring resistance, electric current and magnitude of voltage, be particularly related to the autoselector of the range of digital multimeter measuring instrument, when measuring a certain object, after the range of this kind universal measuring instrument in having selected a certain measurement automatically, by modulus (A/D) conversion, be converted into the reading of measured value.
Traditional measurement instrument such as universal measuring instrument all just obtains measured value after choosing range.So also just exist the trouble that manually to select range to each measurement.
Therefore, the digital multimeter measuring instrument only needs along with the automatic selection of range just can be carried out this measurement after improving, thereby has avoided this class trouble.With regard to the method for this automatic selection range, a kind of is that range is selected with a digital value that converts, and another kind is that range is selected by the separate counts of high-speed counter and low speed counter.
In the previous case, the tested analogue value is to count after A/D conversion, if count value is transformed into next range when exceeding the full scale numerical value of existing range again, thereby feasible conversion from minimum range to the maximum amount journey will expend the plenty of time.
Under latter event, the demonstration of measured value is needed high precision, thus adopt the low speed counter, and the not high function resemble the range of other accuracy requirement is then used high-speed counter, thus make it can select range rapidly.Yet range should be changed once at least, and be limited by the time constant of A/D converter its switching time.
The objective of the invention is for a kind of automatic range selector being provided for the digital multimeter measuring instrument, this selector switch makes can obtain quickly when measuring certain research object to require once above automatic range to select.
This purpose of the present invention can be by selecting range to realize with digital signal form, and this digital signal is to compare the back with the internal reference level that utilizes a parallel A/D converter by scrambler generation at the measured value of an attenuator.
Automatic range selector according to digital multimeter measuring instrument provided by the present invention comprises: one is used for the attenuator of the tested magnitude of voltage of Research on attenuation object; One is used for the analog output signal of described attenuator is converted to the A/D converter of digital signal; The counter that the digital output signal of described A/D converter is counted; One parallel A/D converter is in order to provide the Parallel Digital output signal by the output signal of attenuator is compared with internal reference voltage; With a steering logic and measurement range selector, in order to control the output voltage of attenuator according to the digital output signal of described parallel A/D converter.
Above and other objects of the present invention, feature and advantage will from the reference accompanying drawing to the following explanation of its most preferred embodiment solve clearer, in the accompanying drawing:
Fig. 1 is a conventional digital formula universal measuring instrument circuit diagram;
Fig. 2 is the operational flowchart of explanation conventional digital formula universal measuring instrument;
Fig. 3 is another embodiment of conventional digital formula universal measuring instrument shown in Figure 2;
Fig. 4 is the block scheme according to digital multimeter measuring instrument of the present invention; With
Fig. 5 is the circuit diagram that is used for selecting automatically a parallel A/D converter of range according to the present invention.
Refer now to all accompanying drawings, describe the present invention in more detail.
Fig. 1 illustrates the circuit diagram of a traditional digital multimeter measuring instrument, and this universal measuring instrument is by selecting range once the digital value that converts.This traditional digital universal measuring instrument comprises an attenuator 1, in order to the tested magnitude of voltage Vin that decays, one A/D converter 2, convert digital signal in order to output with attenuator 1, one counter 3, be used for to the digital signal of A/D converter 2 count and a steering logic with measure range selector 4, thereby go to control the attenuation ratio of attenuator 1 with the output signal of A/D converter 2 sum counters 3 control signal is added to A/D converter 2 sum counters 3.
When the tested input voltage vin of research object was added to A/D converter 2 by attenuator 1, A/D converter 2 was digital signal, is counted by the digital signal after 3 pairs of conversions of counter this analog signal conversion.
When being counted the full scale value that exceeds existing range, steering logic and range selector 4 are just controlled attenuator 1 range are transformed into the next one.At this moment, the output of attenuator 1 just is reduced to 1/10 of tested voltage.Therefore, if institute adds tested voltage when very big, then owing to will be converted to the highlyest from minimum range, this selection course just need expend the considerable time.For example, concerning input voltage vin was the situation of 30V, selection operation through the range that 2V and 20V are converted to 200V, just showed that measured value is " 30.0V " from minimum 200.0mv range.When the time of a range of conversion needed 400ms, this selection operation time must be changed 1.6 seconds.
Fig. 2 is depicted as the process flow diagram of the sequence of operation of explanation traditional digital multimeter measuring instrument shown in Figure 1.
In the operation,, calculate the output voltage V x of the attenuator 1 that will be added to A/D converter 2 according to tested input voltage vin at step S3 to N=0.At step S4 and S5, judge that voltage Vx is whether in the set-point scope, if voltage Vx illustrates then that in this set-point scope this value is in showing range, so show this voltage Vx at step S8.But,, then increase range and repeat same operation at step S11 if voltage Vx value exceeds existing range.When measured value greatly when exceeding the maximum range of permission, then show that by step S10 quantity to be measured transships.
Fig. 3 is another embodiment of this traditional digital multimeter measuring instrument.In Fig. 3, range is by at a high speed and low speed counter separate counts and selecting, this universal measuring instrument comprises an attenuator, the tested voltage Vin that is used for the Research on attenuation object, each low speed and high-speed a/d converter 5 and 6 are converted to digital signal in order to the output voltage V x with attenuator 1, each low speed and high- speed counter 7 and 8 are received low speed and high-speed a/d converter 5 and 6 respectively, in order to each numeral output is counted, change device device 5 with a steering logic and range selector 4 in order to give low speed and high-speed a/d, 6 sum counters 7,8 provide control signal and control the attenuation ratio of attenuator 1 by the output of A/D converter 5 and 6.
The tested input voltage vin of research object is added to low speed and high-speed a/d converter 5 and 6 by attenuator 1, respectively is converted into digital signal so be added to each simulating signal of A/D converter 5 and 6.The numeral output of low-speed a/d converter 5 is by low speed counter 7 countings, the numeral output of high-speed a/d converter 6 is then by high-speed counter 8 countings, in the case, low speed counter 7 counts 1,2 successively, 3 ... and high-speed counter 8 counts 10 successively, 20,30 ..., like this, fast 5 to 10 times than the counting of low speed counter 7 of high-speed counters 8, the count value of high-speed counter 8 are added to steering logic and measure range selector 4 to remove to select required range by control attenuator 1.
Yet,, spend in the gate time measured on the range still with millisecond meter, and limited by the time constant of high-speed a/d converter 6 even use this method.Required area is just very big if A/D converter 6 also comprises the then many chips of resistance and capacitor and additional external element.
Fig. 4 is the calcspar of the digital multimeter measuring instrument of explanation one embodiment of the present of invention.Among Fig. 4, this digital multimeter measuring instrument comprises: attenuator 1 is used for the tested input voltage vin of predetermined unit decay from research object; An A/D converter 2 is used to change the output voltage V x of attenuator 1; One counter 3 is used for counting and give latch and display that one counting output is provided to an output of A/D converter 2; One three bit parallel A/D converter 10 is used for providing Parallel Digital output by the output Vx of receiving attenuation device 1; With a steering logic and range selector 4, in order to select range by 3 bit parallel A/D converters 10.Steering logic and range selector 4 control attenuators 1 are with the predetermined unit tested voltage of decaying.Its steering logic produces logical signal with control A/D converter 2 sum counters 3, meanwhile controls the driving of 3 bit parallel A/D converters 10.Though this embodiment of the present invention is described as 3 bit parallel A/D converters particularly, the present invention is not limited thereto.
Fig. 5 is the circuit diagram in order to the 3 bit parallel A/D converters 10 of selecting range, with explanation one embodiment of the invention.Among Fig. 5, comparing unit 12 is used for the output voltage V x of attenuator 1 is compared with reference voltage, and these parts 12 comprise: the divider resistance R1～R6 and the comparator C P1～CP5 that are used to distribute voltage.By reference voltage+a that resistance R 1～R6 sets up ,+b, 0 ,-b and-a is added to the in-phase input end (+) of comparator C P1～CP5 respectively.The output voltage V x of attenuator 1 is added to the inverting input (-) of comparator C P1 to be compared～CP5 jointly, and the output of comparator C P1～CP5 is added to a scrambler EN, so that 3 position digital signals to be provided.
In the present invention, thus the tested input voltage vin of research object is added to voltage Vx after attenuator 1 produces decay.The output voltage V x that attenuator 1 produces is distributed by the resistance R 1～R6 according to switch (conversion) control.
Tested output voltage V x both had been added to 3 bit parallel A/D converters 10 and also had been added to A/D converter 2.3 bit parallel A/D converters 10 are compared voltage Vx with internal reference voltage, thereby provide 3 position digital signals with control attenuator 1 for steering logic and range selector 4.Output voltage V x with the corresponding attenuator 1 of range like this, just is provided.In the case, with the same reference voltage ± aV of voltage Vx, ± bV and OV compare 3 bit parallel A/D converters 10 by comparator C P1～CP5, and produce 3 bit parallel digital signals.
Next step, if confirm tested input voltage vin really greater than the permission voltage of existing range in the control logic unit, then measurement range selection unit control attenuator 1 is so that input voltage vin is reduced to 1/10 and to make output voltage V x be 1/10 of input voltage vin.
Repeat these steps and just can select a correct range.For example, though from minimum range to the maximum amount journey, these steps will repeat 4 or 5 times, but since parallel switching time very short, so can avoid the too much time consumption that causes by " overload ".Measurement range selection is to finish under the automatic zero set (AZS) state of A/D converter 2 simultaneously.
In operation with reference to the 3 bit parallel A/D converters of figure 5, the output voltage V x of attenuator 1 is added to the inverting input (-) of comparator C P1～CP5, and is the reference voltage+a of resistor R 1～R6 institute dividing potential drop ,+b, 0 ,-b and-a then is added to its in-phase input end (+).
Like this, the output voltage V x of attenuator 1 just compares with reference voltage, and the output of comparator C P1～CP5 is added to scrambler EN, thereby produces the output of 3 bit parallels numeral.In the case, promptly corresponding if voltage Vx surpasses reference voltage+a with outrange, and if voltage Vx does not arrive reference voltage-b, then corresponding to " owing range " (under-range).
Scrambler EN can finish the coding of 6 kinds of situations by 5 comparator C P1～CP5, and the output of 3 bit parallels numeral is provided for steering logic and range selector 4, so that attenuator 1 is subjected to control to be converted, thus selected suitable range.The final range of output voltage V x is selected in an extremely short time, and range is in case selected, and the value of output voltage V x to be converted then is under the automatic zero set (AZS) cycle status of A/D converter 2.A/D converter 2 will be converted to digital signal at the voltage Vx in the final selected range, and the digital output signal of 3 pairs of A/D converters 2 of counter is counted then.Like this, but use just certain desired value of energy measurement of very short time, promptly directly produced because only changed once from this class measured value of A/D converter 2.
Mentioned as top, in automatic range selection course according to the present invention, a certain measurement range is discerned and is provided parallel digital signal to go to control the switch transition of attenuator and will be converted to digital signal to be shown corresponding to the measured value of last range by a scrambler by a certain parallel A/D converter.Therefore, the present invention can shorten Measuring Time under the several times change over condition in not delaying the selected automatically process of range.
The present invention is in no way limited to the foregoing description situation.For a person skilled in the art, the various remodeling of disclosed embodiment of this invention and other embodiment may be conspicuous under reference instructions situation of the present invention.Therefore, appended claims covers attempt all remodeling or other embodiment that falls in the essential scope of the present invention.
Claims (2)
1, a kind of automatic range selecting arrangement of digital multimeter measuring instrument comprises:
Attenuator is used for the tested magnitude of voltage of Research on attenuation object;
A/D converter is used for the analog output signal of described attenuator is converted to digital signal;
Counter is used for the digital output signal of described A/D converter is counted;
Parallel A/D converter is used for comparing fast with internal reference voltage by the output signal with described attenuator, so that the Parallel Digital output signal to be provided; With
Steering logic and range selector are used for the output voltage according to the digital output signal control attenuator of parallel A/D converter.
2, according to the automatic range selecting arrangement of the digital multimeter measuring instrument of claim 1, wherein said parallel A/D converter comprises:
Resistor provides reference voltage by supply voltage is carried out dividing potential drop;
Comparer compares the output voltage of described attenuator with reference voltage; With
Scrambler is linked described comparer, is used to provide the Parallel Digital output signal.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1019890020222A KR920009910B1 (en) | 1989-12-29 | 1989-12-29 | Measurement auto-selector circuit of digital multi-meter |
| KR20222/89 | 1989-12-29 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN1052951A true CN1052951A (en) | 1991-07-10 |
Family
ID=19294272
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN90108459A Pending CN1052951A (en) | 1989-12-29 | 1990-10-13 | The automatic range selector of digital multimeter measuring instrument |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JPH03211471A (en) |
| KR (1) | KR920009910B1 (en) |
| CN (1) | CN1052951A (en) |
| DE (1) | DE4032714A1 (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2008034306A1 (en) * | 2006-09-18 | 2008-03-27 | Jiajing Zang | A digital multimeter with automatic measurement selection function |
| CN101825652A (en) * | 2009-03-05 | 2010-09-08 | 鸿富锦精密工业（深圳）有限公司 | Automatic range selector of measuring equipment |
| CN101706524B (en) * | 2009-11-18 | 2011-12-28 | 北京普源精电科技有限公司 | Data collection device and data collection method thereof |
| CN102466749A (en) * | 2010-11-03 | 2012-05-23 | 北京普源精电科技有限公司 | Method for automatically determining appropriate measuring range and universal meter |
| CN102854357A (en) * | 2012-08-24 | 2013-01-02 | 李诚德 | Multi-range automatic gear shifting device |
| CN111025008A (en) * | 2019-12-31 | 2020-04-17 | 深圳市有方科技股份有限公司 | Voltage detection method and device |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19712078A1 (en) * | 1997-03-11 | 1998-10-01 | Tektronix Berlin Gmbh | Circuit for selecting measuring range, e.g. for digital multimeter |
| WO2011008845A1 (en) | 2009-07-14 | 2011-01-20 | Toray Plastics (America), Inc. | Crosslinked polyolefin foam sheet with exceptional softness, haptics, moldability, thermal stability and shear strength |
-
1989
- 1989-12-29 KR KR1019890020222A patent/KR920009910B1/en active IP Right Grant
-
1990
- 1990-10-13 CN CN90108459A patent/CN1052951A/en active Pending
- 1990-10-15 DE DE4032714A patent/DE4032714A1/en not_active Ceased
- 1990-10-15 JP JP2273519A patent/JPH03211471A/en active Pending
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2008034306A1 (en) * | 2006-09-18 | 2008-03-27 | Jiajing Zang | A digital multimeter with automatic measurement selection function |
| CN101149399B (en) * | 2006-09-18 | 2013-04-17 | 臧佳菁 | Digital multimeter for automatically selecting measuring function |
| CN101825652A (en) * | 2009-03-05 | 2010-09-08 | 鸿富锦精密工业（深圳）有限公司 | Automatic range selector of measuring equipment |
| CN101706524B (en) * | 2009-11-18 | 2011-12-28 | 北京普源精电科技有限公司 | Data collection device and data collection method thereof |
| CN102466749A (en) * | 2010-11-03 | 2012-05-23 | 北京普源精电科技有限公司 | Method for automatically determining appropriate measuring range and universal meter |
| CN102466749B (en) * | 2010-11-03 | 2015-12-09 | 北京普源精电科技有限公司 | A kind of method and multimeter automatically determining suitable range |
| CN102854357A (en) * | 2012-08-24 | 2013-01-02 | 李诚德 | Multi-range automatic gear shifting device |
| CN111025008A (en) * | 2019-12-31 | 2020-04-17 | 深圳市有方科技股份有限公司 | Voltage detection method and device |
Also Published As
| Publication number | Publication date |
|---|---|
| KR910012730A (en) | 1991-07-31 |
| DE4032714A1 (en) | 1991-07-11 |
| JPH03211471A (en) | 1991-09-17 |
| KR920009910B1 (en) | 1992-11-06 |
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| C01 | Deemed withdrawal of patent application (patent law 1993) | ||
| WD01 | Invention patent application deemed withdrawn after publication |