CN205375255U - 4 -20mA output circuit with but high accuracy self -checking - Google Patents
4 -20mA output circuit with but high accuracy self -checking Download PDFInfo
- Publication number
- CN205375255U CN205375255U CN201521105589.8U CN201521105589U CN205375255U CN 205375255 U CN205375255 U CN 205375255U CN 201521105589 U CN201521105589 U CN 201521105589U CN 205375255 U CN205375255 U CN 205375255U
- Authority
- CN
- China
- Prior art keywords
- resistance
- circuit
- output
- outfan
- cpu control
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn - After Issue
Links
Landscapes
- Amplifiers (AREA)
Abstract
The application discloses a 4 -20mA output circuit with but high accuracy self -checking, including CPU control circuit, signaling conversion circuit, voltage -controlled constant -current source circuit, output circuit and closed loop feedback circuit, CPU control circuit's DA output is connected to signaling conversion circuit, signaling conversion circuit is connected to voltage -controlled constant -current source circuit, voltage -controlled constant current source circuit connection is to output circuit and closed loop feedback circuit, closed loop feedback circuit is connected to CPU control circuit's AD input for signal after will handling passes through the AD input to be inputed to CPU control circuit, and CPU control circuit still is used for carrying out operation to the signal of received closed loop feedback circuit feedback, and it is right that the ratio of precision is carried out to the data and the desired value that obtain the processing, and according to its DA output of comparison results dynamic adjustment. So the scheme realizes the self -checking of AD feedback, the final output signal of dynamic adjustment for the 4 -20mA signal of high accuracy is stabilized to the final output.
Description
Technical field
The application relates to circuit applied technical field, specifically, relate to a kind of there is high accuracy can the 4-20mA output circuit of self-inspection.
Background technology
All can there is the 4-20mA output interface of standard in the most monitoring device of industrial occasions, the real-time pick-up of various signals of collection in worksite be exported to PLC, DCS dispatch control system, to realize the purpose of process control.4-20mA is as important cue, and its reliability, precision, high temperature performance all can directly affect the reliability of whole Process Control System, it may be said that precision is more high, and system is more reliable.
Monitoring device is affected by the factor such as holistic cost and volume on the market, general 4-20mA output accuracy grade is not high, mostly it is only capable of realizing the accuracy class of 1%, better can reach 0.5% accuracy class, what can reach 0.2% accuracy class is all the instrument of very high-end costliness, and this is mainly by the limitation of following 3 aspects:
(1) when exporting semaphore request precision and being higher, the figure place of D/A also will increase therewith.According to engineering experience, generally in industrial instrument D/A increase to 12 could realize 0.2% accuracy class, but no matter select 12 D/A chips, still select the single-chip microcomputer of built-in 12 D/A, price is all costly, and tens yuan are not to dozens of yuan etc.；
(2) additionally industrial occasions application is complicated, and variations in temperature is very big, can directly affect 4-20mA output accuracy.So the components and parts temperature in 4-20mA circuit is floated coefficient requirements significantly high, particularly to D/A and voltage reference.According to engineering experience, the accuracy class temperature drift coefficient that can realize 0.2% needs to be better than 20ppm/ DEG C, selects D/A that temperature drift coefficient is better than 20ppm/ DEG C and voltage reference that device cost can be significantly increased；
(3) general 4-20mA output circuit, single-chip microcomputer only opened loop control D/A or PWM exports, and output result cannot be monitored, when some component failure, when causing 4-20mA simulation output function abnormal, it is impossible to alert in time and notify user.
Utility model content
In view of this, technical problems to be solved in this application there is provided a kind of there is high accuracy can the 4-20mA output circuit of self-inspection, build closed-loop feedback circuit, realize A/D and feed back self-inspection, dynamically adjust final output signal, make finally to export stable, high-precision 4-20mA signal, substantially increase the stability of system.
In order to solve above-mentioned technical problem, the application has following technical scheme:
A kind of there is high accuracy can the 4-20mA output circuit of self-inspection, it is characterised in that including: cpu control circuit, signaling conversion circuit, controlled constant-current source circuit, output circuit and closed-loop feedback circuit,
The D/A outfan of described cpu control circuit is connected to described signaling conversion circuit, for output current signal；
Described signaling conversion circuit is connected to described controlled constant-current source circuit, for receiving the current signal of the D/A outfan output of described cpu control circuit, current signal is converted to voltage signal, and provides voltage signal to described controlled constant-current source circuit；
Described controlled constant-current source circuit is connected to described output circuit and described closed-loop feedback circuit, for receiving the voltage signal that described signaling conversion circuit sends, voltage signal is converted into the output of 4-20mA signal to described output circuit, and sends to described closed-loop feedback circuit after voltage signal is processed；
Described closed-loop feedback circuit is connected to the A/D input of described cpu control circuit, for the signal after process is inputted to cpu control circuit by A/D input, described cpu control circuit is additionally operable to the signal of the described closed-loop feedback circuit feedback received is carried out calculation process, carry out ratio of precision pair by processing the data obtained with expected value, and dynamically adjust its D/A output according to comparing result.
Preferably, wherein:
Described signaling conversion circuit comprises the first resistance and the second resistance, and the first end of described first resistance connects the D/A outfan of described cpu control circuit and the first end of described second resistance, the second end ground connection of described first resistance；Second end of described second resistance connects described controlled constant-current source circuit.
Preferably, wherein:
Described controlled constant-current source circuit includes the first operational amplifier, the second operational amplifier, audion, the 3rd resistance, the 4th resistance, the 5th resistance, the 6th resistance, the 7th resistance and the 9th resistance,
The in-phase input end of described first operational amplifier is connected to the second end of the second resistance in described signaling conversion circuit, inverting input is connected to the first end of described 3rd resistance and the outfan of described second operational amplifier, and the outfan of described first operational amplifier is connected to the first end of the 9th resistance；Second end of described 9th resistance is connected to described audion；
The base stage of described audion is connected to the second end of described 9th resistance, and colelctor electrode connects power supply, and emitter stage connects the first end of described 4th resistance and the first end of described 5th resistance；Second end of described 5th resistance is connected to described output circuit and the first end of described 7th resistance；Second end of described 4th resistance is connected to the second end of described 3rd resistance and the inverting input of described second operational amplifier；
The in-phase input end of described second operational amplifier is connected to the second end of described 7th resistance and the first end of described 6th resistance, the second end ground connection of described 6th resistance；The outfan of described second operational amplifier is connected to described closed-loop feedback circuit.
Preferably, wherein:
Described closed-loop feedback circuit includes the 8th resistance and electric capacity, first end of described 8th resistance is connected in described controlled constant-current source circuit the outfan of the second operational amplifier, second end is connected to the first end of described electric capacity and the A/D input of described cpu control circuit, the second end ground connection of described electric capacity.
Preferably, wherein:
Described output circuit includes the tenth resistance, protection device TVS and AO outfan,
First end of described tenth resistance connects the second end of the 5th resistance in described controlled constant-current source circuit; second end of described tenth resistance is connected to first end of described protection device TVS and the first end of described AO outfan, second end of described protection device TVS and the second end ground connection of described AO outfan.
Compared with prior art, method described herein, reach following effect:
First, provided herein have high accuracy can the 4-20mA output circuit of self-inspection, adopt the A/D feedback detection output signal of cpu control circuit, it is possible to dynamically adjust the D/A output of cpu control circuit so that final export desirable 4 20mA current values.
Second, provided herein have high accuracy and in the 4-20mA output circuit of self-inspection, can select low cost CPU, and its internal D/A is 10, temperature drift coefficient 30ppm/ DEG C；Internal A/D is 10, temperature drift coefficient 10ppm/ DEG C；Internal voltage reference is temperature drift coefficient 15ppm/ DEG C；Although D/A can not meet 20ppm/ DEG C, the precision of 12, but the application is ingenious builds closed-loop feedback circuit, dynamically adjust final output signal, utilize internal A/D and the excellent temperature drift performance of internal voltage reference, the 4-20mA signal of final output is highly stable, meets 0.2 grade of high accuracy index, substantially increase the reliability of system in the industrial temperature range of-25 70 DEG C.
3rd, provided herein have high accuracy and can the 4-20mA output circuit of self-inspection can pass through to feed back the 4-20mA analog output signal that self-inspection monitor in real time is final, when the reasons such as component failure cause 4-20mA simulation output function abnormal, alert in time and notify user, improve the reliability of whole Process Control System.
4th, provided herein have high accuracy and the 4-20mA output circuit of self-inspection can realize high performance index, makes product have more competitiveness, is suitable for modularity mass production, greatly reduces the cost of whole monitoring system.
Accompanying drawing explanation
Accompanying drawing described herein is used for providing further understanding of the present application, constitutes the part of the application, and the schematic description and description of the application is used for explaining the application, is not intended that the improper restriction to the application.In the accompanying drawings:
Fig. 1 be of the present utility model described a kind of there is high accuracy can the 4-20mA output circuit structure block diagram of self-inspection；
Fig. 2 be of the present utility model described a kind of there is high accuracy can the detailed construction schematic diagram of 4-20mA output circuit of self-inspection.
Detailed description of the invention
As employed some vocabulary in the middle of description and claim to censure specific components.Those skilled in the art are it is to be appreciated that hardware manufacturer may call same assembly with different nouns.This specification and claims are not used as distinguishing in the way of assembly by the difference of title, but are used as the criterion distinguished with assembly difference functionally." comprising " as mentioned in the middle of description and claim in the whole text is an open language, therefore should be construed to " comprise but be not limited to "." substantially " referring in receivable range of error, those skilled in the art can solve described technical problem within the scope of certain error, basically reaches described technique effect.Additionally, " coupling " word comprises any directly and indirectly electric property coupling means at this.Therefore, if a first device described in literary composition is coupled to one second device, then represents described first device and can directly be electrically coupled to described second device, or be indirectly electrically coupled to described second device by other devices or the means that couple.Description subsequent descriptions is implement the better embodiment of the application, and right described description is for the purpose of the rule so that the application to be described, is not limited to scope of the present application.The protection domain of the application is when being as the criterion depending on the defined person of claims.
Embodiment 1
Shown in Figure 1 for herein described a kind of have high accuracy can the specific embodiment of 4-20mA output circuit 100 of self-inspection, including cpu control circuit 10, signaling conversion circuit 11, controlled constant-current source circuit 12, output circuit 13 and closed-loop feedback circuit 14.Wherein, the D/A outfan of cpu control circuit 10 is connected to described signaling conversion circuit 11, for output current signal.Described signaling conversion circuit 11 is connected to described controlled constant-current source circuit 12, for receiving the current signal of the D/A outfan output of described cpu control circuit 10, current signal is converted to voltage signal, and provides voltage signal to described controlled constant-current source circuit 12.Described controlled constant-current source circuit 12 is connected to described output circuit 13 and described closed-loop feedback circuit 14, for receiving the voltage signal that described signaling conversion circuit 11 sends, voltage signal is converted into the output of 4-20mA signal to described output circuit 13, and sends to described closed-loop feedback circuit 14 after voltage signal is processed.Described closed-loop feedback circuit 14 is connected to the A/D input of described cpu control circuit 10, for the signal after process is inputted to cpu control circuit 10 by A/D input, described cpu control circuit 10 is additionally operable to the signal of described closed-loop feedback circuit 14 feedback received is carried out calculation process, carry out ratio of precision pair by processing the data obtained with expected value, and dynamically adjust its D/A output according to comparing result.
Embodiment 2
At the enterprising step refining in the basis of Fig. 1, the signaling conversion circuit 11 in Fig. 1 comprises the first resistance R1 and the second resistance R2 further, referring to Fig. 2.First end of described first resistance R1 connects the D/A outfan of described cpu control circuit 10 and first end of described second resistance R2, the second end ground connection of described first resistance R1；Second end of described second resistance R2 connects described controlled constant-current source circuit 12.
Controlled constant-current source circuit 12 in Fig. 1 farther includes first operational amplifier the 21, second operational amplifier 22, audion the 23, the 3rd resistance R3, the 4th resistance R4, the 5th resistance R5, the 6th resistance R6, the 7th resistance R7 and the nine resistance R9, referring to Fig. 2.The in-phase input end of described first operational amplifier 21 is connected in described signaling conversion circuit 11 second end of the second resistance R2, inverting input is connected to first end of described 3rd resistance R3 and the outfan of described second operational amplifier 22, and the outfan of described first operational amplifier 21 is connected to first end of the 9th resistance R9；Power end one end of described first operational amplification circuit 21 connects 24V power supply, other end ground connection.Second end of described 9th resistance R9 is connected to described audion 23；The base stage of described audion 23 is connected to second end of described 9th resistance R9, and colelctor electrode connects 24V power supply, and emitter stage connects first end of described 4th resistance R4 and first end of described 5th resistance R5；Second end of described 5th resistance R5 is connected to described output circuit 13 and first end of described 7th resistance R7；Second end of described 4th resistance R4 is connected to second end of described 3rd resistance R3 and the inverting input of described second operational amplifier 22；The in-phase input end of described second operational amplifier 22 is connected to second end of described 7th resistance R7 and first end of described 6th resistance R6, the second end ground connection of described 6th resistance R6；The outfan of described second operational amplifier 22 is connected to described closed-loop feedback circuit 14.
Closed-loop feedback circuit 14 in Fig. 1 farther includes the 8th resistance R8 and electric capacity C2, referring to Fig. 2.First end of described 8th resistance R8 is connected in described controlled constant-current source circuit 12 outfan of the second operational amplifier 22, and the second end is connected to first end of described electric capacity C2 and the A/D input of described cpu control circuit 10, the second end ground connection of described electric capacity C2.
Output circuit 13 in Fig. 1 farther includes the tenth resistance R10, protection device TVS24 and AO outfan, as shown in Figure 2.First end of described tenth resistance R10 connects second end of the 5th resistance R5 in described controlled constant-current source circuit 12; second end of described tenth resistance R10 is connected to first end of described protection device TVS24 and the first end AO+ end of described AO outfan, second end of described protection device TVS24 and the second end AO-end ground connection of described AO outfan.
The vdd terminal of the cpu control circuit 10 in Fig. 1 is via electric capacity C1 ground connection.
The application has high accuracy can in the 4-20mA output circuit 100 of self-inspection, and the CPU model of employing can be C8051F330, with low cost, and its internal D/A is 10, and temperature floats coefficient 30ppm/ DEG C；Internal A/D is 10, temperature drift coefficient 10ppm/ DEG C；Internal voltage reference is temperature drift coefficient 15ppm/ DEG C.Although the D/A output of the CPU of this model can not meet 20ppm/ DEG C, the precision of 12, but the application is ingenious builds closed-loop feedback circuit, dynamically adjust final output signal, utilize internal A/D and the excellent temperature drift performance of internal voltage reference, the 4-20mA signal of final output is highly stable, meets 0.2 grade of high accuracy index, substantially increase the reliability of system in the industrial temperature range of-25 70 DEG C.
During work, the D/A outfan output current signal of cpu control circuit 10, being converted into voltage signal after the sampled resistance i.e. effect of the first resistance R1 to export to controlled constant-current source circuit 12, the signal received is converted into 4-20mA signal and exports the AO outfan of output circuit 13 by controlled constant-current source circuit 12；The voltage signal fed back to through the first operational amplifier 21 and the second operational amplifier 22 enters the A/D input of cpu control circuit 10 through the 8th resistance R8 and electric capacity C2.Cpu control circuit 10 is acquired computing and result and actual expected value is carried out precision difference comparison, dynamically adjusts its D/A output, final output desirably high accuracy 4-20mA signal.
In controlled constant-current source circuit 12, audion 23 can improve the output driving force of whole circuit, the current signal of output is converted into voltage signal through the 5th resistance R5, then through the second operational amplifier the 22, the 3rd resistance R3, the 4th resistance R4, the 6th resistance R6 and the seven resistance R7 amplification after, export signal with the D/A end of cpu control circuit 10 to compare, through the 5th resistance R5, the tenth resistance R10 and AO outfan constant current output 4-20mA signal.
By various embodiments above it can be seen that the application existence provides the benefit that:
First, provided herein have high accuracy can the 4-20mA output circuit of self-inspection, adopt the A/D feedback detection output signal of cpu control circuit, it is possible to dynamically adjust the D/A output of cpu control circuit so that final export desirable 4 20mA current values.
Second, provided herein have high accuracy and in the 4-20mA output circuit of self-inspection, can select low cost CPU, and its internal D/A is 10, temperature drift coefficient 30ppm/ DEG C；Internal A/D is 10, temperature drift coefficient 10ppm/ DEG C；Internal voltage reference is temperature drift coefficient 15ppm/ DEG C；Although D/A can not meet 20ppm/ DEG C, the precision of 12, but the application is ingenious builds closed-loop feedback circuit, dynamically adjust final output signal, utilize internal A/D and the excellent temperature drift performance of internal voltage reference, the 4-20mA signal of final output is highly stable, meets 0.2 grade of high accuracy index, substantially increase the reliability of system in the industrial temperature range of-25 70 DEG C.
3rd, provided herein have high accuracy and can the 4-20mA output circuit of self-inspection can pass through to feed back the 4-20mA analog output signal that self-inspection monitor in real time is final, when the reasons such as component failure cause 4-20mA simulation output function abnormal, alert in time and notify user, improve the reliability of whole Process Control System.
4th, provided herein have high accuracy and the 4-20mA output circuit of self-inspection can realize high performance index, makes product have more competitiveness, is suitable for modularity mass production, greatly reduces the cost of whole monitoring system.
Those skilled in the art are it should be appreciated that embodiments herein can be provided as method, device or computer program.Therefore, the application can adopt the form of complete hardware embodiment, complete software implementation or the embodiment in conjunction with software and hardware aspect.And, the application can adopt the form at one or more upper computer programs implemented of computer-usable storage medium (including but not limited to disk memory, CD-ROM, optical memory etc.) wherein including computer usable program code.
Described above illustrate and describes some preferred embodiments of the application, but as previously mentioned, it is to be understood that the application is not limited to form disclosed herein, it is not to be taken as the eliminating to other embodiments, and can be used for other combinations various, amendment and environment, and in utility model contemplated scope described herein, can be modified by the technology of above-mentioned instruction or association area or knowledge.And the change that those skilled in the art carry out and change are without departing from spirit and scope, then all should in the protection domain of the application claims.
Claims (5)
1. one kind there is high accuracy can the 4-20mA output circuit of self-inspection, it is characterised in that including: cpu control circuit, signaling conversion circuit, controlled constant-current source circuit, output circuit and closed-loop feedback circuit,
The D/A outfan of described cpu control circuit is connected to described signaling conversion circuit, for output current signal；
Described signaling conversion circuit is connected to described controlled constant-current source circuit, for receiving the current signal of the D/A outfan output of described cpu control circuit, current signal is converted to voltage signal, and provides voltage signal to described controlled constant-current source circuit；
Described controlled constant-current source circuit is connected to described output circuit and described closed-loop feedback circuit, for receiving the voltage signal that described signaling conversion circuit sends, voltage signal is converted into the output of 4-20mA signal to described output circuit, and sends to described closed-loop feedback circuit after voltage signal is processed；
Described closed-loop feedback circuit is connected to the A/D input of described cpu control circuit, for the signal after process is inputted to cpu control circuit by A/D input, described cpu control circuit is additionally operable to the signal of the described closed-loop feedback circuit feedback received is carried out calculation process, carry out ratio of precision pair by processing the data obtained with expected value, and dynamically adjust its D/A output according to comparing result.
2. according to claim 1 a kind of there is high accuracy can the 4-20mA output circuit of self-inspection, it is characterised in that
Described signaling conversion circuit comprises the first resistance and the second resistance, and the first end of described first resistance connects the D/A outfan of described cpu control circuit and the first end of described second resistance, the second end ground connection of described first resistance；Second end of described second resistance connects described controlled constant-current source circuit.
3. according to claim 2 a kind of there is high accuracy can the 4-20mA output circuit of self-inspection, it is characterised in that
Described controlled constant-current source circuit includes the first operational amplifier, the second operational amplifier, audion, the 3rd resistance, the 4th resistance, the 5th resistance, the 6th resistance, the 7th resistance and the 9th resistance,
The in-phase input end of described first operational amplifier is connected to the second end of the second resistance in described signaling conversion circuit, inverting input is connected to the first end of described 3rd resistance and the outfan of described second operational amplifier, and the outfan of described first operational amplifier is connected to the first end of the 9th resistance；Second end of described 9th resistance is connected to described audion；
The base stage of described audion is connected to the second end of described 9th resistance, and colelctor electrode connects power supply, and emitter stage connects the first end of described 4th resistance and the first end of described 5th resistance；Second end of described 5th resistance is connected to described output circuit and the first end of described 7th resistance；Second end of described 4th resistance is connected to the second end of described 3rd resistance and the inverting input of described second operational amplifier；
The in-phase input end of described second operational amplifier is connected to the second end of described 7th resistance and the first end of described 6th resistance, the second end ground connection of described 6th resistance；The outfan of described second operational amplifier is connected to described closed-loop feedback circuit.
4. according to claim 3 a kind of there is high accuracy can the 4-20mA output circuit of self-inspection, it is characterised in that
Described closed-loop feedback circuit includes the 8th resistance and electric capacity, first end of described 8th resistance is connected in described controlled constant-current source circuit the outfan of the second operational amplifier, second end is connected to the first end of described electric capacity and the A/D input of described cpu control circuit, the second end ground connection of described electric capacity.
5. having high accuracy according to Claims 1 to 4 arbitrary described a kind of can the 4-20mA output circuit of self-inspection, it is characterised in that
Described output circuit includes the tenth resistance, protection device TVS and AO outfan,
First end of described tenth resistance connects the second end of the 5th resistance in described controlled constant-current source circuit; second end of described tenth resistance is connected to first end of described protection device TVS and the first end of described AO outfan, second end of described protection device TVS and the second end ground connection of described AO outfan.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201521105589.8U CN205375255U (en) | 2015-12-27 | 2015-12-27 | 4 -20mA output circuit with but high accuracy self -checking |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201521105589.8U CN205375255U (en) | 2015-12-27 | 2015-12-27 | 4 -20mA output circuit with but high accuracy self -checking |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN205375255U true CN205375255U (en) | 2016-07-06 |
Family
ID=56257469
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201521105589.8U Withdrawn - After Issue CN205375255U (en) | 2015-12-27 | 2015-12-27 | 4 -20mA output circuit with but high accuracy self -checking |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN205375255U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105446408A (en) * | 2015-12-27 | 2016-03-30 | 北京易艾斯德科技有限公司 | Self-inspection 4-20 mA output circuit with high precision |
-
2015
- 2015-12-27 CN CN201521105589.8U patent/CN205375255U/en not_active Withdrawn - After Issue
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105446408A (en) * | 2015-12-27 | 2016-03-30 | 北京易艾斯德科技有限公司 | Self-inspection 4-20 mA output circuit with high precision |
| CN105446408B (en) * | 2015-12-27 | 2018-05-04 | 北京易艾斯德科技有限公司 | It is a kind of have high accuracy can self-test 4-20mA output circuits |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN105446408A (en) | Self-inspection 4-20 mA output circuit with high precision | |
| CN100412755C (en) | In-time adjusting circuit for central processor frequency | |
| CN103034273A (en) | Numerically-controlled constant current source | |
| CN107102680A (en) | A kind of low noise low pressure difference linear voltage regulator | |
| CN205375255U (en) | 4 -20mA output circuit with but high accuracy self -checking | |
| CN109343638A (en) | A kind of High Precision Low Temperature drift bipolarity Multichannel constant-current source circuit | |
| CN102478435A (en) | Thermal resistor temperature conversion method and device thereof for signal simulation | |
| CN104198783A (en) | Power detection circuit with temperature compensation characteristic and powered device | |
| CN103278196A (en) | Integrated sensor | |
| CN203706005U (en) | Voltage stabilizing circuit | |
| CN204667241U (en) | A kind of low pressure difference linear voltage regulator | |
| Chou et al. | Stability robustness of continuous-time perturbed descriptor systems | |
| CN102346464A (en) | 0-20mA or 4-20mA direct current analog quantity output device | |
| CN205571673U (en) | Digitally controlled's contravariant gas shielded arc welding control circuit module | |
| CN203324859U (en) | FPGA-based temperature compensation control circuit | |
| CN206440799U (en) | A kind of circuit checker | |
| KR20230004599A (en) | Digital quantity output circuit, digital quantity output device and digital quantity output system | |
| CN106253891B (en) | High-precision current-voltage conversion module for converting 4-20 mA into +/-10V | |
| CN207440717U (en) | Cloud computing server platform based on big data | |
| CN204215195U (en) | Multiple analog quantity sensor data acquisition system (DAS) | |
| CN103488226A (en) | Output voltage control circuit | |
| CN203812130U (en) | Transient boosting circuit for low-voltage-difference linear voltage stabilizer and low-voltage-difference linear voltage stabilizer | |
| CN206759415U (en) | Resistor-type analog input interface circuit | |
| CN109992034A (en) | A kind of low pressure difference linear voltage regulator | |
| CN104977974B (en) | A kind of integral control module for super-current power unit test system |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| AV01 | Patent right actively abandoned |
Granted publication date: 20160706 Effective date of abandoning: 20180504 |
|
| AV01 | Patent right actively abandoned |