CN205353169U - Automatic gear adjustment's digital multimeter - Google Patents
Automatic gear adjustment's digital multimeter Download PDFInfo
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- CN205353169U CN205353169U CN201521027623.4U CN201521027623U CN205353169U CN 205353169 U CN205353169 U CN 205353169U CN 201521027623 U CN201521027623 U CN 201521027623U CN 205353169 U CN205353169 U CN 205353169U
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Abstract
The utility model provides an automatic gear adjustment's digital multimeter, including the AD converter, parallel connection is in each other DC voltage shelves measurement circuit, alternating voltage shelves measurement circuit, the resistance shelves measurement circuit of the analog input end of AD converter, and connect the display of the digital output end of AD converter, the analog input of AD converter end still is connected with the selector, and this selector includes three IO interface, one every IO interface connection with selector assorted opto -coupler, three opto -coupler respectively with gear select switch on DC voltage shelves measurement circuit, alternating voltage shelves measurement circuit, the resistance shelves measurement circuit links to each other. The utility model discloses an automatic gear adjustment's digital multimeter has solved user of service and has falsely dropped the problem of selecting the universal meter gear and leading to the misjudge probably to cause the serious consequence, has avoided the manual trouble of switching the universal meter gear, has increased the rationality that the digital multimeter gear was selected, has improved user of service's work efficiency.
Description
Technical field
This utility model relates to the technical field of circuit tester, particularly relates to a kind of digimer being automatically adjusted gear.
Background technology
Onsite application personnel find at work, conventional digimer is when using the resistance of resistance grade measurement current transform er secondary circuit, if this loop has bigger alternating voltage or DC voltage, circuit tester will be displayed as " 0L " resistance (i.e. the resistance value of display during open circuit of secondary loop of current transformer), user of service is without carefully searching reason, to think that this Current Transformer Secondary coil is opened a way by mistake, namely current transformer damages needs to change, thus not only increase equipment cost, it is also possible to because erroneous judgement causes serious consequence.Therefore, digimer can automatically select gear and be particularly important, and existing digimer haves much room for improvement.
Summary of the invention
In order to solve above-mentioned technical problem, the utility model proposes a kind of digimer being automatically adjusted gear, with the analog signals size cases according to externally input, gear is automatically switched to DC voltage shelves, alternating voltage shelves or resistance grade.
The technical solution of the utility model is as follows:
A kind of digimer being automatically adjusted gear, including A/D converter, it is connected in parallel with each other the DC voltage shelves at the analog input end of described A/D converter and measures loop, alternating voltage shelves measure loop, resistance grade measures loop, and it is connected to the display of the digital output end of described A/D converter, the analog input end of described A/D converter is also associated with selector, this selector includes three I/O interfaces, each I/O interface connects an optocoupler matched with described selector, three optocouplers measure loop with described DC voltage shelves respectively, alternating voltage shelves measure loop, resistance grade is measured the GSS Gear Select Switch on loop and is connected.
The utility model has the advantages that: it is simple and reasonable for structure, can according to the change of externally input DC voltage, alternating voltage or resistive mode analog quantity signal, selector is utilized to control three different optocouplers conductings and disconnect, and the selection switch of respective notch is controlled by these optocouplers, thus realizing the automatic switchover of DC voltage, alternating voltage or three different gears of resistance, simplify the job step of user of service's onsite application circuit tester, it is facilitated quickly to judge measurement result, improve work efficiency, and avoid to falsely drop and select the problem that gear is likely to cause.
Accompanying drawing explanation
Fig. 1 structural representation of the present utility model；
Fig. 2 this utility model DC voltage shelves measure the schematic diagram in loop；
Fig. 3 this utility model alternating voltage shelves measure the schematic diagram in loop；
Fig. 4 this utility model resistance grade measures the schematic diagram in loop.
Detailed description of the invention
Understandable for enabling above-mentioned purpose of the present utility model, feature and advantage to become apparent from, below in conjunction with the drawings and specific embodiments, this utility model is described in further detail.
Embodiment
As shown in Figures 1 to 4, a kind of digimer being automatically adjusted gear, including A/D converter, it is connected in parallel with each other the DC voltage shelves at the analog input end of described A/D converter and measures loop, alternating voltage shelves measure loop, resistance grade measures loop, and it is connected to the display of the digital output end of described A/D converter, the analog input end of described A/D converter is also associated with selector, this selector includes three I/O interfaces, each I/O interface connects an optocoupler matched with described selector, three optocouplers measure loop with described DC voltage shelves respectively, alternating voltage shelves measure loop, resistance grade is measured the GSS Gear Select Switch on loop and is connected.
This utility model carries out hardware modifications on the basis of conventional digital circuit tester, is mainly the mode automatically selected being made up of selector, optocoupler by that a part of hardware replacement of its manual switching gear.Wherein, selector can adopt single-chip microcomputer to realize, by single-chip microcomputer is enrolled program, it is possible to controls the optocoupler being connected on I/O interface, and then realizes the selection to gear.Those skilled in the art according to actual needs, can also select other electronic devices and components to serve as selector；Similarly, when adopting single-chip microcomputer as selector, writing corresponding program for those skilled in the art of the present technique, belong to conventional technological know-how, this is no longer discussed in detail by this utility model.
Such as Fig. 2, measure in loop at DC voltage shelves, in figure, 1. normal opened contact represents DC voltage shelves GSS Gear Select Switch, 1. contact closes and represents that circuit tester switches to DC voltage shelves, the DC voltage analog signals then measured by two measurement test pencils of circuit tester V/ Ω and COM inputs to A/D converter, and A/D converter converts the measurement into digital data transmission and shows result to display.Same, the GSS Gear Select Switch being also provided with correspondence in loop, resistance grade measurement loop is measured at alternating voltage shelves.The difference is that, such as Fig. 3, in alternating voltage shelves measurement loop, compared with accompanying drawing 2, accompanying drawing 3 adds rectification module, it is therefore an objective to convert the alternating voltage analog signals measured to DC voltage analog signals；Such as Fig. 4; loop is measured at resistance grade; add protection circuit; its effect is that protection circuit tester avoids it to be burned; VREF+ and VREF-is the power supply that circuit tester is supplied to external circuit; measured resistance is connected with reference resistance, and measured resistance two ends DC voltage analog signals reaches in A/D converter, thus showing result in the display.
Such as Fig. 1, that a part of hardware of digimer manual switching gear has been improved by this utility model.In figure, VCC provides positive supply for optocoupler, pull-up resistor R plays the effect of current limliting, optocoupler A, B, C control respectively correspondence 1., 2., 3. normal opened contact, 1., 2., 3. normal opened contact correspondence respectively control DC voltage, alternating voltage and three different GSS Gear Select Switch in resistance measurement loop.
By accompanying drawing 2, accompanying drawing 3, accompanying drawing 4 it can be seen that DC voltage shelves, alternating voltage shelves, resistance grade measurement to analog signals finally all input IN+ and the IN-terminal to A/D converter.As shown in Figure 1, this analog input is to the A/D and GND terminal of single-chip microcomputer, the single-chip microcomputer size cases according to this analog quantity, changed by the low and high level of three I/O interfaces of programme-control, within the same time, it is interfaced to by programme controlled three I/O and has one for low level more, all the other are high level, therefore three optocouplers at most have one within the same time and have forward voltage, namely an optocoupler is at most had to be in conducting state, all the other are for being not turned on, purpose is to make circuit tester can only be switched on a gear in the same time, two or three gears can not be switched to simultaneously.The conducting situation of optocoupler directly control corresponding contact opening and closing 1., 2., 3., thus realizing this digimer to automatically select the function of gear.
Illustrated below: if the analog quantity size cases that single-chip microcomputer inputs according to A/D and GND terminal, output result after program judges is that I/O interface 1 sets low level (0), I/O interface 2 sets high level (1), I/O interface 3 sets high level (1), owing to VCC provides positive supply to optocoupler, then now optocoupler A one end is high level, one end is low level, what bear is forward voltage, therefore optocoupler A conducting, optocoupler B and optocoupler C is high level due to two ends, do not bear forward voltage and so there is no conducting, 1. normal opened contact corresponding for optocoupler A closes, now circuit tester automatically selects to DC voltage shelves, show the DC voltage size of correspondence over the display, judge for user.Automatically select alternating voltage shelves or resistance grade situation is similar, no longer illustrate one by one herein.
A kind of digimer being automatically adjusted gear of the present utility model, compared with the digimer of prior art, it has the beneficial effects that:
(1) this digimer according to the analog signals size cases of externally input, can automatically select DC voltage shelves, alternating voltage shelves or resistance grade, it is not necessary to switch gear manually.
(2) user of service falsely drops and selects circuit tester gear and cause that erroneous judgement measurement result is likely to result in serious consequence, and digimer of the present utility model can avoid this problem.
(3) digimer of the present utility model can allow user of service quickly judge measurement result, improves produced on-site work efficiency.
Above-listed detailed description is illustrating for this utility model possible embodiments, and this embodiment is also not used to limit the scope of the claims of the present utility model, and all equivalences done without departing from this utility model are implemented or change, and are intended to be limited solely by the scope of the claims of this case.
Claims (1)
1. the digimer being automatically adjusted gear, including A/D converter, it is connected in parallel with each other the DC voltage shelves at the analog input end of described A/D converter and measures loop, alternating voltage shelves measure loop, resistance grade measures loop, and it is connected to the display of the digital output end of described A/D converter, it is characterized in that, the analog input end of described A/D converter is also associated with selector, this selector includes three I/O interfaces, each I/O interface connects an optocoupler matched with described selector, three optocouplers measure loop with described DC voltage shelves respectively, alternating voltage shelves measure loop, resistance grade is measured the GSS Gear Select Switch on loop and is connected.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201521027623.4U CN205353169U (en) | 2015-12-11 | 2015-12-11 | Automatic gear adjustment's digital multimeter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201521027623.4U CN205353169U (en) | 2015-12-11 | 2015-12-11 | Automatic gear adjustment's digital multimeter |
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| Publication Number | Publication Date |
|---|---|
| CN205353169U true CN205353169U (en) | 2016-06-29 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201521027623.4U Active CN205353169U (en) | 2015-12-11 | 2015-12-11 | Automatic gear adjustment's digital multimeter |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106053911A (en) * | 2016-07-22 | 2016-10-26 | 无锡职业技术学院 | Simple universal meter |
| CN112505385A (en) * | 2020-11-16 | 2021-03-16 | 广东电网有限责任公司 | Universal meter and use method thereof |
-
2015
- 2015-12-11 CN CN201521027623.4U patent/CN205353169U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106053911A (en) * | 2016-07-22 | 2016-10-26 | 无锡职业技术学院 | Simple universal meter |
| CN112505385A (en) * | 2020-11-16 | 2021-03-16 | 广东电网有限责任公司 | Universal meter and use method thereof |
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| GR01 | Patent grant |