CN206818800U - A kind of resistance measuring instrument - Google Patents
A kind of resistance measuring instrument Download PDFInfo
- Publication number
- CN206818800U CN206818800U CN201720578360.9U CN201720578360U CN206818800U CN 206818800 U CN206818800 U CN 206818800U CN 201720578360 U CN201720578360 U CN 201720578360U CN 206818800 U CN206818800 U CN 206818800U
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- Prior art keywords
- resistance
- dpdt relay
- double
- controller
- relay
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Abstract
The utility model discloses a kind of resistance measuring instrument, including bidirectional constant source, voltage acquisition and amplifier, a/d converter, bidirectional constant source, measuring resistance and measured resistance are linked to be series loop, the output end of the voltage acquisition and amplifier is electrically connected by a/d converter and controller, controller and the display terminal electrical connection, also include being used for control voltage collection and amplifier is connected on the switching switch module at standard resistor at two terminals or measured resistance both ends, controller electrically connects with the control terminal of switching switch.The utility model circuit structure is simple, and forward and reverse Constant Electric Current flow valuve need not be strictly equal caused by bidirectional constant source, reduces the requirement to hardware precision；The Leakage Current of electronic switch can be avoided to the influence of measurement accuracy；The temperature drift of measurement result is only relevant with the temperature drift of measuring resistance, selects low excursion with temperature measuring resistance, it is possible to improves measurement accuracy of the instrument in the case of wide temperature；Directional jamming can be eliminated to be influenceed to caused by test result.
Description
Technical field
The utility model belongs to field of measuring technique, more particularly to a kind of resistance measuring instrument.
Background technology
At present, the resistance measuring instrument used using the two-way method of testing principle measurement priming system resistance of low current includes two-way perseverance
Stream source, voltage acquisition and amplifier, a/d converter.During measurement, positive (reverse) electric current is produced first with bidirectional constant source, and
Positive (reverse) electric current is passed through into measured resistance.Then using on voltage acquisition and amplifier and a/d converter measurement measured resistance
Forward direction (reverse) voltage, and the forward direction measured (reverse) voltage and known positive (reverse) current value are divided by, obtain by
The forward resistance value and backward resistance value of measuring resistance.Finally, take the average value of forward resistance value and backward resistance value i.e. available
Measured resistance value.
Resistance measuring instrument of the prior art has the disadvantages that：
First, forward current value caused by bidirectional constant source and reverse value of current must be strictly equal, otherwise resistance measurement
Precision is low.
Second, switch the sense of current in bidirectional constant source using electronic switch, due to electronic switch leakage current is big and with
Temperature change is big, brings larger uncertainty to test result, and measurement result precision is low.
3rd, a reference source used in bidirectional constant source and a/d converter is highly susceptible to the influence of temperature, so as to surveying
Test result impacts；In addition, the drift of voltage acquisition and amplifier can also impact to test result.When this resistance measurement
When instrument is applied to wide warm field, influence of the temperature to test result will be very big, because temperature drift is affected by multiple factors, tool
There is very big uncertainty, computer can not be used to carry out temperature-compensating, measurement result precision is low.
Utility model content
The purpose of this utility model is, for above-mentioned the deficiencies in the prior art, there is provided a kind of resistance measuring instrument.
In order to solve the above technical problems, technical scheme is used by the utility model：
A kind of resistance measuring instrument, including bidirectional constant source, voltage acquisition and amplifier, a/d converter, it is structurally characterized in that
Bidirectional constant source, measuring resistance and measured resistance are linked to be series loop, and the output end of the voltage acquisition and amplifier passes through AD
Converter and controller electrical connection, controller and the display terminal electrical connection, in addition to gather and amplify for control voltage
Device is connected on the switching switch module at standard resistor at two terminals or measured resistance both ends, and the control terminal of controller and switching switch is electrically connected
Connect.
By said structure, a/d converter conversion is the measured resistance under forward current Iz and reverse current If effects
With the magnitude of voltage in measuring resistance.Because the resistance of measuring resistance is known, due in series circuit, ohmically magnitude of voltage
With its resistance value direct proportionality, so, computer by the magnitude of voltage application percentage calculating method collected processing can obtain
To measured resistance value.
As a kind of preferred embodiment, the switching switch module includes the first dpdt relay, and controller passes through the
The coil ground connection of double-pole double-throw relay, double closed contacts of the first dpdt relay are connected on the two of measured resistance respectively
End, the double of the first dpdt relay open the both ends that contact is connected on measuring resistance respectively, pair of the first dpdt relay
Closed contact opens input of the contact as the first dpdt relay, output end and the electricity of the first dpdt relay with double
Pressure collection and amplifier electrical connection.
As another preferred embodiment, the switching switch module includes the first dpdt relay, and controller passes through
The coil ground connection of first dpdt relay, double closed contacts of the first dpdt relay are connected on the two of measuring resistance respectively
End, the double of the first dpdt relay open the both ends that contact is connected on measured resistance respectively, pair of the first dpdt relay
Closed contact opens input of the contact as the first dpdt relay, output end and the electricity of the first dpdt relay with double
Pressure collection and amplifier electrical connection.
As a kind of preferred embodiment, in addition to the second dpdt relay, controller passes through the second DPDT relay
The coil ground connection of device；The bidirectional constant source includes first resistor, second resistance, 3rd resistor and operational amplifier, the first electricity
The first end and power electric connection of resistance, the second end of first resistor electrically connect with the inverting input of operational amplifier, the second electricity
Resistance and 3rd resistor are serially connected between power supply and ground, the in-phase input end of operational amplifier access second resistance and 3rd resistor it
Between；The second end with first resistor, the output end of operational amplifier are electrically connected double closed contacts of second dpdt relay respectively
Connect, double output ends for opening contact respectively with operational amplifier of the second dpdt relay, the second end of first resistor are electrically connected
Connect, double closed contacts of the second dpdt relay and it is double open input of the contact as the second dpdt relay, second
The output end of dpdt relay is linked to be loop with measured resistance, measuring resistance.
Compared with prior art, the utility model circuit structure is simple, and has advantages below：
First, forward and reverse Constant Electric Current flow valuve caused by bidirectional constant source need not be strictly equal, as long as being surveyed in forward and reverse
The short time is kept constant during amount, i.e. just (anti-) is acted on measured resistance Rx and measuring resistance Rs to electric current Iz (If), AD
When converter gathers measured resistance Rx and measuring resistance Rs voltage respectively, continuous current is protected only in two acquisition time sections
It is fixed to keep steady.Because in series circuit, the magnitude of voltage in each series resistance is directly proportional to their resistance value, and this is in electricity
The conclusion drawn in the case of stream identical.Because the AD conversion of measured resistance and voltage in measuring resistance is not to carry out simultaneously, institute
With, it is desirable to keep electric current constant during two AD conversion.Because AD conversion interval is very short, electric current height is realized in a short time
Precision is constant to be easily achieved.Resistance survey is carried out as a result of the voltage Comparison Method in measured resistance and measuring resistance
Amount, so, voltage amplification and AD conversion before AD conversion do not require high accuracy, High Linear, and only require output and input
It is one-to-one, i.e., dull corresponding can, reduces the requirement to hardware precision.
Second, two mechanical relay switch have been used in constant-current source and voltage signal switching, electronic cutting can be avoided
Influence of the Leakage Current of pass to measurement accuracy.
3rd, because directional jamming potential will not change with the change of the test sense of current, so using bidirectional measurement
During method, influence of the directional jamming to test result in forward and reverse test is：Amplitude is equal, opposite polarity.Will be positive and negative
Test result, which is averaged, can just exclude influence of the directional jamming potential to test result, at the same can also exclude a reference source and
The temperature drift in bidirectional constant source influences to caused by measuring accuracy.Therefore the utility model measurement result temperature drift only with
The temperature drift of measuring resistance is relevant, as long as selection low excursion with temperature measuring resistance, it is possible to improves instrument in the case of wide temperature
Measurement accuracy.
Brief description of the drawings
Fig. 1 is the structural representation of the utility model resistance measuring instrument.
Fig. 2 is the circuit diagram in bidirectional constant source.
Wherein, 1 is bidirectional constant source, and 2 be the first dpdt relay, and 3 be a/d converter, and 4 be power supply, and 5 be control
Device, 6 be voltage acquisition and amplifier, and 7 be display terminal, and 8 be the second dpdt relay, and Rx is measured resistance, and Rs is mark
Quasi- resistance, R1 are first resistor, and R2 is second resistance, and R3 is 3rd resistor, and A is operational amplifier, and Iz is positive continuous current,
If is reverse continuous current.
Embodiment
As depicted in figs. 1 and 2, resistance measuring instrument includes bidirectional constant source 1, voltage acquisition and amplifier 6, a/d converter 3,
It is structurally characterized in that bidirectional constant source 1, measuring resistance Rs and measured resistance Rx are linked to be series loop, the voltage acquisition and amplification
The output end of device 6 is electrically connected by a/d converter 3 and controller 5, and the controller 5 and display terminal 7 electrically connect, in addition to is used
The switching switch module at measuring resistance Rs both ends or measured resistance Rx both ends, control are connected in control voltage collection and amplifier 6
Device 5 electrically connects with the control terminal of switching switch.
The switching switch module includes the first dpdt relay 2, and controller 5 passes through the first dpdt relay
2 coil ground connection.Double closed contacts of first dpdt relay 2 are connected on measured resistance Rx both ends respectively, and the first double-pole is double
Throw relay 2 it is double open contact be connected on respectively measuring resistance Rs both ends (connection can also be exchanged, i.e. the first DPDT after
Double closed contacts of electrical equipment 2 are connected on measuring resistance Rs both ends respectively, and the double of the first dpdt relay 2 open contact and are connected on respectively
Measured resistance Rx both ends).Double closed contacts of first dpdt relay 2 open contact as the first DPDT relay with double
The input of device 2, the output end of the first dpdt relay 2 electrically connect with voltage acquisition and amplifier 6.
Resistance measuring instrument also includes the second dpdt relay 8, and controller 5 passes through the second dpdt relay 8
Coil is grounded；The bidirectional constant source 1 includes first resistor R1, second resistance R2,3rd resistor R3 and operational amplifier A, the
One resistance R1 first end electrically connects with power supply 4, and first resistor R1 the second end and the inverting input of operational amplifier A are electrically connected
Connect, second resistance R2 and 3rd resistor R3 are serially connected between power supply 4 and ground, the in-phase input end access second of operational amplifier A
Between resistance R2 and 3rd resistor R3；Double closed contacts of second dpdt relay 8 respectively the second end with first resistor R1,
The output end electrical connection of operational amplifier A, to open contact defeated with operational amplifier A respectively by the second dpdt relay 8 double
Go out the second end electrical connection at end, first resistor R1, double closed contacts of the second dpdt relay 8 open contact as second with double
The input of dpdt relay 8, output end and measured resistance Rx, the measuring resistance Rs of the second dpdt relay 8 connect
Into loop.
First dpdt relay 2 can switch voltage acquisition and the tested electricity of amplifying circuit collection under the control of controller 5
Hinder the magnitude of voltage on Rx or measuring resistance Rs.
Second dpdt relay 8 can switch bidirectional constant source 1 under the control of controller 5 and export positive constant current Iz
Or reverse constant current If.
The analog voltage signal measured can be converted into digital voltage signal by a/d converter 3.
Power supply 4 is used to provide different supply voltages for whole resistance measuring instrument.
Controller 5 is used for the work for controlling whole measuring instrument, while the magnitude of voltage that AD conversion obtains is handled.
The step of measuring resistance using the utility model resistance measuring instrument is as follows：
A. measured resistance Rx and measuring resistance Rs are serially connected in the both ends of bidirectional constant source 1；
B. control bidirectional constant source 1 to export positive continuous current Iz, measure the magnitude of voltage U at measured resistance Rx both ends respectively1
With the magnitude of voltage U at measuring resistance Rs both ends2；
C. control bidirectional constant source 1 to export reverse continuous current If, measure the magnitude of voltage U at measured resistance Rx both ends respectively3
With the magnitude of voltage U at measuring resistance Rs both ends4；
D. the resistance for trying to achieve measured resistance Rx isWherein RSFor measuring resistance Rs resistance.
Embodiment of the present utility model is described above in conjunction with accompanying drawing, but the utility model is not limited to
The embodiment stated, above-mentioned embodiment is only schematical, rather than limitation, this area it is common
Technical staff is not departing from the utility model aims and scope of the claimed protection situation under enlightenment of the present utility model
Under, many forms can be also made, these are belonged within the scope of protection of the utility model.
Claims (4)
1. a kind of resistance measuring instrument, including bidirectional constant source (1), voltage acquisition and amplifier (6), a/d converter (3), its feature
It is, bidirectional constant source (1), measuring resistance (Rs) and measured resistance (Rx) are linked to be series loop, the voltage acquisition and amplification
The output end of device (6) is electrically connected by a/d converter (3) and controller (5), and the controller (5) and display terminal (7) are electrically connected
Connect, in addition to measuring resistance (Rs) both ends or measured resistance (Rx) both ends are connected on for control voltage collection and amplifier (6)
Switch switch module, controller (5) electrically connects with the control terminal of switching switch.
2. resistance measuring instrument as claimed in claim 1, it is characterised in that the switching switch module includes the first DPDT
Relay (2), controller (5) are grounded by the coil of the first dpdt relay (2), the first dpdt relay (2)
Double closed contacts be connected on measured resistance (Rx) both ends respectively, the double of the first dpdt relay (2) open contact and are connected on respectively
The both ends of measuring resistance (Rs), double closed contacts of the first dpdt relay (2) open contact as the first DPDT with double
The input of relay (2), the output end of the first dpdt relay (2) electrically connect with voltage acquisition and amplifier (6).
3. resistance measuring instrument as claimed in claim 1, it is characterised in that the switching switch module includes the first DPDT
Relay (2), controller (5) are grounded by the coil of the first dpdt relay (2), the first dpdt relay (2)
Double closed contacts be connected on measuring resistance (Rs) both ends respectively, the double of the first dpdt relay (2) open contact and are connected on respectively
The both ends of measured resistance (Rx), double closed contacts of the first dpdt relay (2) open contact as the first DPDT with double
The input of relay (2), the output end of the first dpdt relay (2) electrically connect with voltage acquisition and amplifier (6).
4. the resistance measuring instrument as described in any one of claims 1 to 3, it is characterised in that also including the second DPDT relay
Device (8), controller (5) are grounded by the coil of the second dpdt relay (8)；The bidirectional constant source (1) includes first
Resistance (R1), second resistance (R2), 3rd resistor (R3) and operational amplifier (A), the first end and power supply of first resistor (R1)
(4) electrically connect, the second end of first resistor (R1) electrically connects with the inverting input of operational amplifier (A), second resistance (R2)
Power supply (4) is serially connected between ground with 3rd resistor (R3), the in-phase input end access second resistance (R2) of operational amplifier (A)
Between 3rd resistor (R3)；Double closed contacts of second dpdt relay (8) respectively the second end with first resistor (R1),
The output end electrical connection of operational amplifier (A), the second dpdt relay (8) it is double open contact respectively with operational amplifier
(A) the second end electrical connection of output end, first resistor (R1), double closed contacts of the second dpdt relay (8) are opened with double
Input of the contact as the second dpdt relay (8), the output end and measured resistance of the second dpdt relay (8)
(Rx), measuring resistance (Rs) is linked to be loop.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201720578360.9U CN206818800U (en) | 2017-05-23 | 2017-05-23 | A kind of resistance measuring instrument |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201720578360.9U CN206818800U (en) | 2017-05-23 | 2017-05-23 | A kind of resistance measuring instrument |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN206818800U true CN206818800U (en) | 2017-12-29 |
Family
ID=60756099
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201720578360.9U Expired - Fee Related CN206818800U (en) | 2017-05-23 | 2017-05-23 | A kind of resistance measuring instrument |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN206818800U (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106990295A (en) * | 2017-05-23 | 2017-07-28 | 江南工业集团有限公司 | A kind of resistance measuring instrument and resistance measurement method |
| CN109116121A (en) * | 2018-07-27 | 2019-01-01 | 中国科学院寒区旱区环境与工程研究所 | A kind of precision resister measuring instrument suitable for low temperature environment |
| CN112394229A (en) * | 2021-01-21 | 2021-02-23 | 广州思泰信息技术有限公司 | Insulation resistance testing device and insulation resistance testing method |
-
2017
- 2017-05-23 CN CN201720578360.9U patent/CN206818800U/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106990295A (en) * | 2017-05-23 | 2017-07-28 | 江南工业集团有限公司 | A kind of resistance measuring instrument and resistance measurement method |
| CN109116121A (en) * | 2018-07-27 | 2019-01-01 | 中国科学院寒区旱区环境与工程研究所 | A kind of precision resister measuring instrument suitable for low temperature environment |
| CN112394229A (en) * | 2021-01-21 | 2021-02-23 | 广州思泰信息技术有限公司 | Insulation resistance testing device and insulation resistance testing method |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20171229 Termination date: 20200523 |
|
| CF01 | Termination of patent right due to non-payment of annual fee |