CN205788001U - A kind of digital quantity input circuit current foldback circuit - Google Patents
A kind of digital quantity input circuit current foldback circuit Download PDFInfo
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- CN205788001U CN205788001U CN201620680928.3U CN201620680928U CN205788001U CN 205788001 U CN205788001 U CN 205788001U CN 201620680928 U CN201620680928 U CN 201620680928U CN 205788001 U CN205788001 U CN 205788001U
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- quantity input
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Abstract
The utility model discloses a kind of digital quantity input circuit current foldback circuit, including current detection circuit and current-limiting circuit；Between base stage and the emitter stage of the triode amplifier Q1 that described current detection circuit is connected in current-limiting circuit, the input of current-limiting circuit is for being connected with digital quantity input signal, its outfan is for being connected with digital quantity input circuit, and current detection circuit utilizes the operation principle of triode amplifier to control startup and the closedown of current-limiting circuit.This utility model protects the digital quantity input circuit electricity of process channel not damaged by overcurrent effectively, and ensures the normal work of digital quantity input circuit under over-current state, it is ensured that the reliability of process channel, improves the control effect of process control；Realize circuit simple possible, with low cost.
Description
Technical field
This utility model belongs to process control technology field, is specifically related to a kind of digital quantity input circuit overcurrent protection electricity
Road.
Background technology
Process control controls the most in real time, is in continuous flow procedure, computer acquisition testing data timely, presses
Control object is promptly automatically controlled and is automatically adjusted by good value.
In order to realize the computer control to production process, it is necessary to configuration information transmission between computer and production process
With the interface channel of conversion, this passage is referred to as process channel, including input channel and output channel.Believe according to production process
Number feature, and the angle analysis of the process channel technology of correspondence, can be divided into the signal of process channel signal further continuously
Change analog quantity (voltage, electric current, temperature, pressure, speed, flow etc.) and represent with " 0 ", " 1 " digital quantity (switching value,
Pulsed quantity and SOE (Sequence of Event, event sequence) etc.).
The digital quantity signal of input channel is divided into active and passive signal, and active signal is divided into again d. c. voltage signal and friendship
Stream voltage signal, passive signal is generally converted into active signal by offer voltage and detects by passive signal.Along with process
The development in commercial Application of the control technology, the performance of process channel, reliability requirement are particularly important.In digital quantity signal collection
During, the impact that the channel unit caused owing to digital quantity input circuit electric current is excessive damages and collection result mistake causes should
Doing one's utmost to avoid, common measure is to seal in the protective measure such as critesistor, electric fuse at input circuit, but when fusing such as electric fuses
After, signal i.e. lost efficacy, and needed to find and wait repair and replacement channel unit in time, had industry spot process control bigger hidden
Suffer from
Utility model content
For the problems referred to above, the utility model proposes a kind of digital quantity input circuit current foldback circuit, it is to avoid because
The shadow that input channel device damage that digital quantity input circuit electric current is excessive to be caused, Process Control System collection result mistake cause
Ring.
Realizing above-mentioned technical purpose, reach above-mentioned technique effect, this utility model is achieved through the following technical solutions:
A kind of digital quantity input circuit current foldback circuit, including current detection circuit and current-limiting circuit；Described electric current is examined
Between base stage and the emitter stage of the triode amplifier Q1 that slowdown monitoring circuit is connected in current-limiting circuit, the input of current-limiting circuit is used for
Being connected with digital quantity input signal, its outfan is for being connected with digital quantity input circuit, and current detection circuit utilizes audion
The operation principle of amplifier controls the open and close of current-limiting circuit.
Further, described current-limiting circuit includes that triode amplifier Q1 and the first resistance R1, the first resistance R1 are three poles
The collector resistance of pipe amplifier Q1, triode amplifier Q1 is connected with digital quantity input signal by the first resistance R1, three poles
Base stage and the colelctor electrode of pipe amplifier Q1 are connected with digital quantity input circuit the most respectively.
Further, described current detection circuit includes the second resistance R2, the two ends of the second resistance R2 respectively with audion
The base stage of amplifier Q1 and emitter stage connect.
The guard method of a kind of digital quantity input circuit current foldback circuit, comprises the following steps:
Set the protective current limit value Im of digital quantity input circuit；
Obtain the input current Iin that digital quantity input signal produces and the electric current I1 flowing through digital quantity input circuit；
Relatively input current Iin and protective current limit value Im, controls the open and close of current-limiting circuit, thus ensures that digital quantity is defeated
Entry loop is properly functioning.
Further, the protective current limit value Im of described setting digital quantity input circuit specifically includes: defeated according to digital quantity
The running parameter of entry loop: rated operational current is Ia, can pass through carrying current Ib, sets protective current limit value Ia≤Im < Ib.
Further, the described input current Iin and protective current limit value Im that compares, control the open and close of current-limiting circuit, thus
Ensureing that digital quantity input circuit is properly functioning, specifically include: as Iin≤Im, triode amplifier Q1 is operated in cut-off region, stream
Through the electric current I2=0 of current-limiting circuit, current-limiting circuit does not starts, and input circuit electric current Iin is unrestricted for digital quantity, I1=Iin, number
Word amount input circuit is properly functioning.
Further, the described input current Iin and protective current limit value Im that compares, control the open and close of current-limiting circuit, thus
Ensure digital quantity input circuit properly functioning, specifically include: as Iin > Im time, triode amplifier Q1 is operated in amplification region, right
Digital quantity input circuit carries out current limliting, shunting, flows through the electric current I2=Iin-I1 of current-limiting circuit, and current-limiting circuit starts, numeral
The electric current I1 of amount input circuit keeps Im, normally works.
The beneficial effects of the utility model:
The utility model proposes a kind of digital quantity input circuit current foldback circuit, effectively protect the numeral of process channel
Amount input circuit electricity is not damaged by overcurrent, and improves conventional digital quantity input circuit and use the method such as electric fuse protection to cause
The situation that input circuit lost efficacy, it is ensured that digital quantity input circuit remains to normally work under over-current state, it is ensured that process channel
Reliability, improve process control control effect；Without numerous and jumbled testing circuit and control logic, it is achieved circuit simply may be used
Row, cost are the cheapest.
Accompanying drawing explanation
Fig. 1 is current foldback circuit schematic diagram of the present utility model.
Fig. 2 is over-current protection method flow chart of the present utility model.
Detailed description of the invention
In order to make the purpose of this utility model, technical scheme and advantage clearer, below in conjunction with embodiment, to this
Utility model is further elaborated.Should be appreciated that specific embodiment described herein is only in order to explain this practicality
Novel, it is not used to limit this utility model.
Below in conjunction with the accompanying drawings application principle of the present utility model is explained in detail.
As it is shown in figure 1, a kind of digital quantity input circuit current foldback circuit, including current detection circuit and current-limiting circuit；
Between base stage and the emitter stage of the triode amplifier Q1 that described current detection circuit is connected in current-limiting circuit, current-limiting circuit
Input is for being connected with digital quantity input signal, and its outfan is used for being connected with digital quantity input circuit, current detection circuit
The operation principle utilizing triode amplifier controls the open and close of current-limiting circuit.
Further, described current-limiting circuit includes that triode amplifier Q1 and the first resistance R1, the first resistance R1 are three poles
The collector resistance of pipe amplifier Q1, triode amplifier Q1 is connected with digital quantity input signal by the first resistance R1, three poles
Base stage and the colelctor electrode of pipe amplifier Q1 are connected with digital quantity input circuit the most respectively.
Further, described current detection circuit includes the second resistance R2, the two ends of the second resistance R2 respectively with audion
The base stage of amplifier Q1 and emitter stage connect.
As in figure 2 it is shown, the guard method of a kind of digital quantity input circuit current foldback circuit, comprise the following steps:
Set the protective current limit value Im of digital quantity input circuit；Further, described setting digital quantity input circuit
Protective current limit value Im specifically includes: according to the running parameter of digital quantity input circuit: rated operational current is Ia, can pass through pole
Threshold currents Ib, sets protective current limit value Ia≤Im < Ib.
Obtain the input current Iin that digital quantity input signal produces and the electric current I1 flowing through digital quantity input circuit；Pass through
The electric current I1 of digital quantity input circuit, through the second resistance R2, thus produces voltage Ur=I1*R2, Ur along with I1 increase and
Increase.
Relatively input current Iin and protective current limit value Im, controls the switch of current-limiting circuit, thus ensures that digital quantity inputs
Loop is properly functioning.
Further, the described input current Iin and protective current limit value Im that compares, control the switch of current-limiting circuit, thus
Ensureing that digital quantity input circuit is properly functioning, specifically include: as Iin≤Im, Ur is less, not enough so that current-limiting circuit action,
Triode amplifier Q1 is operated in cut-off region, flows through the electric current I2=0 of current-limiting circuit, and current-limiting circuit does not starts, and whole electric currents are all
Being flow through by digital quantity input circuit, input circuit electric current I1 is unrestricted for digital quantity, and I1=Iin, digital quantity input circuit is normal
Run.
Further, the described input current Iin and protective current limit value Im that compares, control the open and close of current-limiting circuit, thus
Ensure digital quantity input circuit properly functioning, specifically include: as Iin > Im time, Ur be more than current-limiting circuit action threshold value, current limliting electricity
Road starts, and triode amplifier Q1 is operated in amplification region, and collector current=current amplification factor * base current, to digital quantity
Input circuit carries out current limliting, shunting, flows through the electric current I2=Iin-I1 of current-limiting circuit, and the electric current I1 of digital quantity input circuit protects
Hold Im, normally work.
It should be noted that in this utility model, term " includes ", " comprising " or its any other variant are intended to contain
Comprising of lid nonexcludability, so that include that the process of a series of key element, method, article or device not only include that those are wanted
Element, but also include other key elements being not expressly set out, or also include for this process, method, article or device
Intrinsic key element.In the case of there is no more restriction, statement " including ... " key element limited, it is not excluded that
Including process, method, article or the device of this key element there is also other identical element.
Described above to the disclosed embodiments, makes professional and technical personnel in the field be capable of or uses this practicality new
Type.Multiple amendment to these embodiments will be apparent from for those skilled in the art, is determined herein
The General Principle of justice can realize in the case of without departing from spirit or scope of the present utility model in other embodiments.Cause
This, this utility model is not intended to be limited to the embodiments shown herein, and is to fit to and principles disclosed herein
The widest scope consistent with features of novelty.
Claims (3)
1. a digital quantity input circuit current foldback circuit, it is characterised in that: include current detection circuit and current-limiting circuit；Institute
State between base stage and the emitter stage of the triode amplifier Q1 that current detection circuit is connected in current-limiting circuit, current-limiting circuit defeated
Entering to hold for being connected with digital quantity input signal, its outfan is for being connected with digital quantity input circuit, and current detection circuit is sharp
The open and close of current-limiting circuit are controlled by the operation principle of triode amplifier.
A kind of digital quantity input circuit current foldback circuit the most according to claim 1: described current-limiting circuit includes three poles
Pipe amplifier Q1 and the first resistance R1, the first resistance R1 are the collector resistance of triode amplifier Q1, triode amplifier Q1
Be connected with digital quantity input signal by the first resistance R1, the base stage of triode amplifier Q1 and colelctor electrode the most respectively with digital quantity
Input circuit connects.
A kind of digital quantity input circuit current foldback circuit the most according to claim 2: described current detection circuit includes
Second resistance R2, the two ends of the second resistance R2 are connected with base stage and the emitter stage of triode amplifier Q1 respectively.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620680928.3U CN205788001U (en) | 2016-06-30 | 2016-06-30 | A kind of digital quantity input circuit current foldback circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620680928.3U CN205788001U (en) | 2016-06-30 | 2016-06-30 | A kind of digital quantity input circuit current foldback circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN205788001U true CN205788001U (en) | 2016-12-07 |
Family
ID=58126384
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201620680928.3U Active CN205788001U (en) | 2016-06-30 | 2016-06-30 | A kind of digital quantity input circuit current foldback circuit |
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| Country | Link |
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| CN (1) | CN205788001U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105974993A (en) * | 2016-06-30 | 2016-09-28 | 南京国电南自美卓控制系统有限公司 | Overcurrent protection circuit and method for digital input circuit |
-
2016
- 2016-06-30 CN CN201620680928.3U patent/CN205788001U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105974993A (en) * | 2016-06-30 | 2016-09-28 | 南京国电南自美卓控制系统有限公司 | Overcurrent protection circuit and method for digital input circuit |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CP01 | Change in the name or title of a patent holder |
Address after: 210032 8 Xing Huo Road, Pukou hi tech Development Zone, Nanjing, Jiangsu Patentee after: Nanjing Guodian Nanzi 710086 Automation Co. Ltd. Address before: 210032 8 Xing Huo Road, Pukou hi tech Development Zone, Nanjing, Jiangsu Patentee before: Nanjing Guodian Nanzi Meizhuo Control System Co.,Ltd. |
|
| CP01 | Change in the name or title of a patent holder |