CN202870145U - DC simulation signal acquisition circuit for public transformation terminal - Google Patents
DC simulation signal acquisition circuit for public transformation terminal Download PDFInfo
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- CN202870145U CN202870145U CN 201220428806 CN201220428806U CN202870145U CN 202870145 U CN202870145 U CN 202870145U CN 201220428806 CN201220428806 CN 201220428806 CN 201220428806 U CN201220428806 U CN 201220428806U CN 202870145 U CN202870145 U CN 202870145U
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- operational amplifier
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- optocoupler
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Abstract
The present utility model discloses a DC simulation signal acquisition circuit for a public transformation terminal. The circuit comprises a voltage and current sampling circuit, an optical coupler isolation circuit and a CPU, the optical coupler isolation circuit is connected after the voltage and current sampling circuit, simulation signals collected by the voltage and current sampling circuit are subjected to signal isolation through the optical coupler isolation circuit, then the signals are sent to an AD sampling end of the CPU. Isolation problems between a public transformation terminal analog input port and a public transformation terminal system are solved, operation stability of the public transformation terminal in various environments is greatly enhanced, requirements of each public transformation terminal using department on public transformation terminal DC analog quantity signal sampling can be satisfied, and normal and safe operation of the public transformation terminal can be ensured.
Description
Technical field
The utility model relates to a kind of signal acquisition circuit, particularly a kind of DC simulation signal acquisition circuit for public transformer terminals.
Background technology
In present prior art scheme, DC analogue quantity input (electric current, voltage) is carried out analog to digital conversion by inputing among the CPU AD module behind the electric resistance partial pressure, and CPU calculates input current value or magnitude of voltage by the voltage value that reads the AD module.Public transformer terminals demand of technical standard has 2 road analog inputs (a tunnel is that current signal and a tunnel is voltage signal): the current signal span is 4-20mA, and the voltage signal span is 0-5V, and error is no more than 5%.According to the electric requirement of public transformer terminals to this 2 tunnel analog input amount: electrical fast transient (eft) and 1.0kV(common mode that can 1.0kV) the lightning surge immunity to interference.We are not difficult to find out thus, prior art all is the AD conversion mouth of direct input system CPU for the input of analog quantity at present, analog input and CPU are in the same power supply signal, unexecuted isolation between analog input and the cpu system, external interference is easy to enter public transformer terminals by analog quantity input and disturbs, public transformer terminals can't normally be moved, even damage.
The utility model content
The purpose of this utility model provides a kind of direct current signal Acquisition Circuit that can improve CPU simulating signal sampling end antijamming capability.
This DC simulation signal acquisition circuit for public transformer terminals that the utility model provides, comprise electric current and voltage sample circuit and CPU, behind the electric current and voltage sample circuit, connect an optical coupling isolation circuit, the electric current and voltage sample circuit carries out the signal isolation with the simulating signal that collects through optical coupling isolation circuit, signal is reached the AD sampling end of CPU again.
In order to improve the antijamming capability of AD sampling end among the CPU, described optical coupling isolation circuit is comprised of operational amplifier D13D, optocoupler D14 and operational amplifier D15, and the inverting input of operational amplifier D13D is by resistance R 1 and simulating signal V
InLink to each other, its in-phase input end and its earth terminal common ground, its power supply termination power V5P0_ISO, capacitor C 26 is connected between its inverting input and the output terminal, and its output terminal links to each other with 1 pin of optocoupler D14 by resistance R 2; 2 pin of optocoupler D14 meet power supply V5P0_ISO, its 3 pin links to each other with the inverting input of operational amplifier D13D, its 4 pin ground connection, its 6 pin links to each other with the inverting input of operational amplifier D15, its 5 pin be connected to simulation ground after the in-phase input end of operational amplifier D15 links to each other; Be connected between the inverting input and its output terminal of operational amplifier D15 after capacitor C 32 and resistance R 3 are in parallel, its power supply termination power V3P3, its ground connection termination simulation ground, its output terminal is with signal V
OutBe sent to the AD sampling end of CPU.
Described optocoupler is the optocoupler D14 that adopts Agilent company to produce, its model is HCNR200, described operational amplifier D13D and described operational amplifier D15 all adopt the chip of MICROCHIP company, the model of described operational amplifier D13D is MCP604, and the model of described operational amplifier D15 is MCP601.Described resistance R 1 equates with described resistance R 2.
The utility model has solved the isolating problem between public transformer terminals analog input port and the public transformer terminals system, make public transformer terminals analog input end can bear electrical fast transient (eft) and the 1.0kV(common mode of 1.0kV) the interference of the forceful electric power signals such as lightning surge, thereby effectively guaranteed the precision of AD sample circuit, and significantly improved the stability that public transformer terminals moves in various environment, each public transformer terminals of to satisfy effectively uses department to the requirement of public transformer terminals DC analogue quantity signal sampling, has guaranteed that public transformer terminals is normal, safe operation.
Description of drawings
Fig. 1 is principle of work block diagram of the present utility model.
Fig. 2 is electric current and voltage sample circuit figure of the present utility model.
Fig. 3 is optical coupling isolation circuit figure of the present utility model.
Fig. 4 is light-coupled isolation prime discharge circuit figure of the present utility model.
Embodiment
The utility model is that DC current input signal (4-20mA) and DC voltage input signal (0-5V) are converted to the collectable voltage signal of AD module among the CPU, by linear optical coupling DC current, DC voltage input signal and system signal is carried out electrical isolation simultaneously.Circuit of the present utility model is comprised of two parts, and first is the electric current and voltage sample circuit; Second portion is optical coupling isolation circuit.
As shown in Figure 2, in the described electric current and voltage sample circuit, behind sample circuit, connect a sampling hold circuit.The 1 the tunnel is 4-20mA dc current signal input, is MCP604 through operational amplifier D1A(model then), export the relevant pin of analog switch chip (model is CD4051) to.The 2 the tunnel is the 0-5V voltage sampling circuit, and the voltage of 0-5V input voltage at the V2 place is 0-3.3V voltage, is MCP604 through amplifier comparator D2A(model then) export the relevant pin of same analog switch chip to.
In order effectively to consider except the high frequency stray voltage, prevent the damage of circuit behind the DC quantity input end misconnection alternating current 220V voltage, behind the sampling input end of current signal, voltage signal, respectively increased a spark pipe (V1 among Fig. 2 and V4).Then, respectively add two diodes (model is L4148, the V2 among Fig. 2 and V3, V5 and V6) at the in-phase input end of operational amplifier D1A and operational amplifier D2A, be not higher than 5V to guarantee input voltage.Simultaneously, so also can holding circuit connect in the anti-situation in DC current or DC voltage input and can not cause damage to sample circuit.
Operational amplifier D1A and operational amplifier D2A use as voltage follower in the described electric current and voltage sample circuit, i.e. U
In=U
OutBecause the input impedance of voltage follower is high, output impedance is low, so that voltage follower has the effect of buffering, isolation, raising load capacity.
During use, connect analog switch behind the electric current and voltage sample circuit, the 11st pin AD_SWTICH by this analog switch switches the input between DC current and voltage.When AD_SWTICH was high level, AD sample rate current signal exported optical coupling isolation circuit to by the 3rd pin com port.When AD_SWTICH was low level, AD sampled voltage signal exported optical coupling isolation circuit to by the 3rd pin com port.
As shown in Figure 3, described optical coupling isolation circuit mainly is in order to guarantee effectively isolation between DC current, voltage acquisition input signal and the public transformer terminals system signal.If this main circuit is realized isolation between signal by linear optical coupling.
Described optical coupling isolation circuit is comprised of operational amplifier D13D, optocoupler D14 and operational amplifier D15, and the inverting input of operational amplifier D13D is by resistance R 1 and simulating signal V
InLink to each other, its in-phase input end and its earth terminal common ground, its power supply termination power V5P0_ISO, capacitor C 26 is connected between its inverting input and the output terminal, and its output terminal links to each other with 1 pin of optocoupler D14 by resistance R 2; 2 pin of optocoupler D14 meet power supply V5P0_ISO, its 3 pin links to each other with the inverting input of operational amplifier D13D, its 4 pin ground connection, its 6 pin links to each other with the inverting input of operational amplifier D15, its 5 pin be connected to simulation ground after the in-phase input end of operational amplifier D15 links to each other; Be connected between the inverting input and its output terminal of operational amplifier D15 after capacitor C 32 and resistance R 3 are in parallel, its power supply termination power V3P3, its ground connection termination simulation ground, its output terminal is with signal V
OutBe sent to the AD sampling end of CPU.
Described optocoupler is the optocoupler that adopts Agilent company to produce, its model is HCNR200, operational amplifier D13D and operational amplifier D15 all adopt the chip of MICROCHIP company, and the model of operational amplifier D13D is MCP604, and the model of operational amplifier D15 is MCP601.
The below derives to the relation of output signal and input signal according to physical circuit.
If input terminal voltage is V
In, output end voltage is V
Out, the input and output electric current that optocoupler guarantees is equal, i.e. the transfer coefficient K1=K2 of optocoupler, obviously V
InAnd V
OutBetween relation depend on relation between R1 and the R3.
The discharge circuit of Fig. 3 is put forward to see, obtain equivalent electrical circuit as shown in Figure 4, the voltage of establishing the inverting input of operational amplifier D13D is V
1, the output end voltage of operational amplifier D13D is V
0, the two satisfies following relation in the undersaturated situation of amplifier:
V in the formula
OOOperational amplifier D13D input differential mode is 0 o'clock output voltage; G is the gain of operational amplifier, and generally its value is larger.
The input current of ignoring the amplifier negative terminal can think that the electric current by R1 is I
P1, got by Ohm law:
If the electric current by the R3 two ends is I
f, by Ohm law as can be known:
Wherein, V
DDBe the voltage of optocoupler 2 pin, the voltage when considering the LED conducting is substantially constant, here be considered as constant.
According to the characteristic of optocoupler, namely
Expression formula substitution following formula with formula (1), formula (2) and formula (3) can get:
With formula (5) by being out of shape:
Formula (6) substitution formula (3) can be got:
The gain G of considering operational amplifier is large especially, can do formula (7) following approximate:
Like this, output signal V
OutWith input signal V
InThe relation of voltage is as follows:
As seen, the output V in the described optical coupling isolation circuit
OutWith input V
InBe directly proportional, and scale-up factor is only fixed by K3 and R1, R3, wherein, K1, K2 are the optocoupler transfer coefficient, and K1=K2 is arranged before, and K3=K2/K1=1 just can reach the purpose that only isolation is not amplified so get R1=R3 herein.
The below carries out parts selection according to Fig. 3 and resistance is determined:
(1) operational amplifier type selecting: can from 0 to V5P0_ISO, need operational amplifier can expire amplitude of oscillation work in order to make input range.In addition, the operating rate of operational amplifier, slew rate can not affect the performance of whole circuit.The MCP604 of MICROCHIP company and MCP601 discharge circuit can satisfy above-mentioned requirements.
(2) resistance is determined: because V5P0_ISO=5V, input is between 0-2V, and output equals input, according to characteristics and the foregoing circuit annexation of operational amplifier, calculates take the working current of optocoupler as 25mA, determines R2=5V/25mA=200 ohm; R3=R1=100K ohm.
Add the protection devices such as spark pipe, diode in the electric current and voltage sample circuit, can be effectively to public transformer terminals system operation protect.D. c. voltage signal and dc current signal Acquisition Circuit have used operational amplifier to believe follower as signal, make between the forward and backward level of the follower circuit to be independent of each other, and have guaranteed the stable, accurate of linear optical coupling buffer circuit input signal.Use linear optical coupling to make the electrical isolation device, effectively guaranteed the electrical isolation between direct current sampled signal and the system signal.Can avoid DC current, voltage input end input high pressure, pulse etc. to disturb impact on public transformer terminals system, guarantee public transformer terminals system stability reliability service.
Claims (4)
1. DC simulation signal acquisition circuit that is used for public transformer terminals, comprise electric current and voltage sample circuit and CPU, it is characterized in that, behind the electric current and voltage sample circuit, connect an optical coupling isolation circuit, reach the AD sampling end of CPU the electric current and voltage sample circuit is isolated the simulating signal that collects by optical coupling isolation circuit after.
2. the DC simulation signal acquisition circuit for public transformer terminals according to claim 1, it is characterized in that, described optical coupling isolation circuit is comprised of operational amplifier D13D, optocoupler D14 and operational amplifier D15, and the inverting input of operational amplifier D13D is by resistance R 1 and simulating signal V
InLink to each other, its in-phase input end and its earth terminal common ground, its power supply termination power V5P0_ISO, capacitor C 26 is connected between its inverting input and the output terminal, and its output terminal links to each other with 1 pin of optocoupler D14 by resistance R 2; 2 pin of optocoupler D14 meet power supply V5P0_ISO, its 3 pin links to each other with the inverting input of operational amplifier D13D, its 4 pin ground connection, its 6 pin links to each other with the inverting input of operational amplifier D15, its 5 pin be connected to simulation ground after the in-phase input end of operational amplifier D15 links to each other; Be connected between the inverting input and its output terminal of operational amplifier D15 after capacitor C 32 and resistance R 3 are in parallel, its power supply termination power V3P3, its ground connection termination simulation ground, its output terminal is with signal V
OutBe sent to the AD sampling end of CPU.
3. the DC simulation signal acquisition circuit for public transformer terminals according to claim 1 and 2, it is characterized in that, described optocoupler is the optocoupler D14 that adopts Agilent company to produce, its model is HCNR200, described operational amplifier D13D and described operational amplifier D15 all adopt the chip of MICROCHIP company, the model of described operational amplifier D13D is MCP604, and the model of described operational amplifier D15 is MCP601.
4. the DC simulation signal acquisition circuit for public transformer terminals according to claim 1 and 2 is characterized in that, described resistance R 1 equates with described resistance R 2.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220428806 CN202870145U (en) | 2012-08-28 | 2012-08-28 | DC simulation signal acquisition circuit for public transformation terminal |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220428806 CN202870145U (en) | 2012-08-28 | 2012-08-28 | DC simulation signal acquisition circuit for public transformation terminal |
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| CN 201220428806 Expired - Lifetime CN202870145U (en) | 2012-08-28 | 2012-08-28 | DC simulation signal acquisition circuit for public transformation terminal |
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Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103760411A (en) * | 2013-11-06 | 2014-04-30 | 国网安徽省电力公司淮南供电公司 | Direct-current bus voltage wave-recording device |
| CN105137234A (en) * | 2015-08-27 | 2015-12-09 | 郑州华力信息技术有限公司 | Multi-channel direct current analog detecting device |
| CN105137292A (en) * | 2015-09-22 | 2015-12-09 | 国家电网公司 | Direct-current signal intelligent acquiring device used for high-voltage cable fault positioning |
| CN106324319A (en) * | 2016-08-02 | 2017-01-11 | 许继集团有限公司 | Direct current voltage and direct current signal sampling circuit |
| CN107422182A (en) * | 2017-06-14 | 2017-12-01 | 珠海中慧微电子股份有限公司 | Direct current energy meter |
| CN108152557A (en) * | 2017-12-26 | 2018-06-12 | 常州三立精图光电有限公司 | Sample circuit is isolated in a kind of feedback current |
| CN109387682A (en) * | 2017-08-04 | 2019-02-26 | 许继集团有限公司 | A kind of alternating voltage and the adaptively sampled circuit of ac current signal and method |
| CN110524090A (en) * | 2019-09-03 | 2019-12-03 | 上海沪工焊接集团股份有限公司 | A kind of current regulating circuit |
| CN110829400A (en) * | 2019-10-25 | 2020-02-21 | 天津航空机电有限公司 | Analog quantity acquisition lightning protection circuit |
| CN111721995A (en) * | 2020-06-23 | 2020-09-29 | 南京海兴电网技术有限公司 | Isolation sampling circuit of direct current voltage signal |
| CN115494291A (en) * | 2022-06-08 | 2022-12-20 | 宁波迦南智能电气股份有限公司 | Dedicated analog quantity acquisition module of energy controller |
-
2012
- 2012-08-28 CN CN 201220428806 patent/CN202870145U/en not_active Expired - Lifetime
Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103760411A (en) * | 2013-11-06 | 2014-04-30 | 国网安徽省电力公司淮南供电公司 | Direct-current bus voltage wave-recording device |
| CN105137234A (en) * | 2015-08-27 | 2015-12-09 | 郑州华力信息技术有限公司 | Multi-channel direct current analog detecting device |
| CN105137292A (en) * | 2015-09-22 | 2015-12-09 | 国家电网公司 | Direct-current signal intelligent acquiring device used for high-voltage cable fault positioning |
| CN105137292B (en) * | 2015-09-22 | 2017-12-26 | 国家电网公司 | Direct current signal intelligent acquisition device for high-tension cable fault location |
| CN106324319A (en) * | 2016-08-02 | 2017-01-11 | 许继集团有限公司 | Direct current voltage and direct current signal sampling circuit |
| CN107422182A (en) * | 2017-06-14 | 2017-12-01 | 珠海中慧微电子股份有限公司 | Direct current energy meter |
| CN109387682A (en) * | 2017-08-04 | 2019-02-26 | 许继集团有限公司 | A kind of alternating voltage and the adaptively sampled circuit of ac current signal and method |
| CN108152557A (en) * | 2017-12-26 | 2018-06-12 | 常州三立精图光电有限公司 | Sample circuit is isolated in a kind of feedback current |
| CN110524090A (en) * | 2019-09-03 | 2019-12-03 | 上海沪工焊接集团股份有限公司 | A kind of current regulating circuit |
| CN110524090B (en) * | 2019-09-03 | 2021-08-20 | 上海沪工焊接集团股份有限公司 | Current regulating circuit |
| CN110829400A (en) * | 2019-10-25 | 2020-02-21 | 天津航空机电有限公司 | Analog quantity acquisition lightning protection circuit |
| CN111721995A (en) * | 2020-06-23 | 2020-09-29 | 南京海兴电网技术有限公司 | Isolation sampling circuit of direct current voltage signal |
| CN115494291A (en) * | 2022-06-08 | 2022-12-20 | 宁波迦南智能电气股份有限公司 | Dedicated analog quantity acquisition module of energy controller |
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Address after: 410205 No. 468 west slope, Changsha hi tech Industrial Development Zone, Changsha, Hunan, Yuelu District, Tongzi Patentee after: WILLFAR INFORMATION TECHNOLOGY Co.,Ltd. Address before: 410205 No. 468 west slope, Changsha hi tech Industrial Development Zone, Changsha, Hunan, Yuelu District, Tongzi Patentee before: HUNAN WEISHENG INFORMATION TECHNOLOGY CO.,LTD. Address after: 410205 No. 468 west slope, Changsha hi tech Industrial Development Zone, Changsha, Hunan, Yuelu District, Tongzi Patentee after: HUNAN WEISHENG INFORMATION TECHNOLOGY CO.,LTD. Address before: 410205 No. 468 west slope, Changsha hi tech Industrial Development Zone, Changsha, Hunan, Yuelu District, Tongzi Patentee before: CHANGSHA WASION INFORMATION TECHNOLOGY Co.,Ltd. |
|
| CX01 | Expiry of patent term | ||
| CX01 | Expiry of patent term |
Granted publication date: 20130410 |