CN104660249B - Two-wire system fieldbus and its interface circuit - Google Patents
Two-wire system fieldbus and its interface circuit Download PDFInfo
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- CN104660249B CN104660249B CN201410849971.3A CN201410849971A CN104660249B CN 104660249 B CN104660249 B CN 104660249B CN 201410849971 A CN201410849971 A CN 201410849971A CN 104660249 B CN104660249 B CN 104660249B
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- interface circuit
- wire system
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- parallel regulator
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Abstract
This application discloses a kind of two-wire system fieldbus and its interface circuit, which includes adjustable precise parallel regulator, N type switch tube, biasing circuit, first resistor and second resistance, wherein：The adjustable precise parallel regulator is the three terminal device for having reference edge, cathode and anode, its cathode connects the anode of bus power source through the biasing circuit, its anode connects the positive input terminal of the signal processing circuit, with reference to the output end for terminating the signal processing circuit；The negative input of the signal processing circuit terminates the cathode of the bus power source；The control of the N type switch tube terminates the cathode of the adjustable precise parallel regulator, and input terminates the anode of the bus power source, and output end connects the positive input terminal of the signal processing circuit through the first resistor；The second resistance connects the output end of the reference edge and the N type switch tube of the adjustable precise parallel regulator, simplifies the circuit structure of the interface circuit of two-wire system fieldbus.
Description
Technical field
The present invention relates to technical field of automation in industry, more specifically to two-wire system fieldbus and its interface electricity
Road.
Background technology
Two-wire system fieldbus (such as FF buses and Profibus-PA buses) is the heat of industrial automation research
Point, it can realize the transmission of signal and electric energy simultaneously using twisted-pair feeder as physical media on same root twisted-pair feeder.
Interface circuit is the unique interface between field device and two-wire system fieldbus, and there are two effects for it：When from
Stable DC stream is drawn on two-wire system fieldbus, gives field device power；Second is that the friendship to signal processing circuit output
(communication information to be transmitted after Manchester's code, bus is output to through signal processing circuit to time-dependent current by field device
On) be modulated, obtain sizeable bus modulation electric current.
Application No. is the patent application documents of CN201180038774.8 to disclose a kind of interface electricity having above-mentioned function
Road, as shown in Figure 1, but the disadvantage is that circuit structure is too complicated.
Invention content
In view of this, a kind of two-wire system fieldbus of present invention offer and its interface circuit, total to simplify two-wire system scene
The circuit structure of the interface circuit of line.
A kind of interface circuit of two-wire system fieldbus, including adjustable precise parallel regulator, N type switch tube, biasing
Circuit, first resistor and second resistance, wherein：
The adjustable precise parallel regulator is the three terminal device for having reference edge, cathode and anode, and cathode is through institute
The anode that biasing circuit connects bus power source is stated, anode connects the positive input terminal of the signal processing circuit, with reference to described in termination
The output end of signal processing circuit；
The negative input of the signal processing circuit terminates the cathode of the bus power source；
The control of the N type switch tube terminates the cathode of the adjustable precise parallel regulator, inputs described in termination
The anode of bus power source, output end connect the positive input terminal of the signal processing circuit through the first resistor；
The second resistance connects the output of the reference edge and the N type switch tube of the adjustable precise parallel regulator
End.
Wherein, the biasing circuit is resistance.
Wherein, the model LMV431 of the adjustable precise parallel regulator.
Wherein, the model TL431 of the adjustable precise parallel regulator.
Wherein, the N type switch tube is NMOS tube.
Wherein, the N type switch tube is NPN type triode.
Wherein, the N type switch tube is N-type Darlington transistor.
A kind of two-wire system fieldbus, including two-wire system fieldbus ontology and with the two-wire system fieldbus ontology
The interface circuit being connected, wherein the interface circuit is any of the above-described kind of interface circuit.
Wherein, the two-wire system fieldbus ontology is FF bus types.
Wherein, the two-wire system fieldbus ontology is Profibus-PA bus types.
It can be seen from the above technical scheme that conducting of the present invention by closed-loop control adjustable precise parallel regulator
And shutdown, make its anode and kept constant with reference to the voltage difference between pole, then for be serially connected in the anode and with reference to pole it
Between two resistance for, due to its circulate respectively bus modulation electric current and signal processing circuit output alternating current,
It only need to rationally adjust the ratio of the two resistance, so that it may modulate electricity so that the alternating current is modulated to sizeable bus
Stream.Compared to the prior art, the present invention uses closed-loop control, is influenced by extraneous factors such as temperature smaller, and closed-loop is small, device
Part usage quantity is few, and circuit structure is simple.
Description of the drawings
In order to more clearly explain the embodiment of the invention or the technical proposal in the existing technology, to embodiment or will show below
There is attached drawing needed in technology description to be briefly described, it should be apparent that, the accompanying drawings in the following description is only this
The embodiment of invention for those of ordinary skill in the art without creative efforts, can also basis
The attached drawing of offer obtains other attached drawings.
Fig. 1 is a kind of interface circuit structure schematic diagram of two-wire system fieldbus disclosed in the prior art；
Fig. 2 is a kind of interface circuit structure schematic diagram of two-wire system fieldbus disclosed by the embodiments of the present invention.
Specific implementation mode
Following will be combined with the drawings in the embodiments of the present invention, and technical solution in the embodiment of the present invention carries out clear, complete
Site preparation describes, it is clear that described embodiments are only a part of the embodiments of the present invention, instead of all the embodiments.It is based on
Embodiment in the present invention, it is obtained by those of ordinary skill in the art without making creative efforts every other
Embodiment shall fall within the protection scope of the present invention.
Referring to Fig. 2, the embodiment of the invention discloses a kind of interface circuits of two-wire system fieldbus, existing to simplify two-wire system
The circuit structure of the interface circuit of field bus, including adjustable precise parallel regulator U, N type switch tube Q, biasing circuit Bias,
First resistor R1 and second resistance R2, wherein：
Adjustable precise parallel regulator U is three end-apparatus for having reference edge Ref, cathode Cathode and anode A node
Part, cathode Cathode meet the positive Vbus of bus power source through biasing circuit Bias+, anode A node connects signal processing circuit
The positive input terminal P of Pin+, reference edge Ref meets the output end P of signal processing circuit Pout；
The negative input end P of signal processing circuit Pin-Meet the cathode Vbus of the bus power source-；
The cathode Cathode of the control termination adjustable precise parallel regulator U of N type switch tube Q, inputs described in termination
The positive Vbus of bus power source+, output end meets the positive input terminal P of signal processing circuit P through first resistor R1in+；
The output end of the reference edge Ref and N type switch tube Q of second resistance R2 connected adjustable precision parallel regulators U.
Biasing circuit Bias in the present embodiment is for providing quiescent point, specifically, biasing circuit Bias can be used
One resistance is realized, to provide bias current for the control terminal of N type switch tube Q.
The characteristic of adjustable precise parallel regulator U in the present embodiment is：When between reference edge Ref and anode A node
When voltage difference is less than the reference voltage of adjustable precise parallel regulator U, reference is worked as in the U cut-offs of adjustable precise parallel regulator
When the voltage difference between Ref and anode A node being held to be more than the reference voltage, the U conductings of adjustable precise parallel regulator.Its model
It selects that LMV431 models (reference voltage of LMV431 is 1.24V, and minimum working current is in 80uA or less) or TL431 types can be used
Number, do not limit to.The temperature drift characteristic of adjustable precise parallel regulator U is good, temperature drift generally within 100ppm/ degrees Celsius,
It is influenced by extraneous factors such as temperature smaller.
NPN type triode can be used in N type switch tube Q in the present embodiment, and (Fig. 2 is only using N type switch tube Q as three pole of NPN type
Pipe is as example), N-type Darlington transistor or NMOS (N-Metal Oxide Semiconductor FET, N-channel metal oxide
Semiconductor field effect transistor).When N type switch tube Q is NPN type triode or N-type Darlington transistor, the control of N type switch tube Q
End is base stage, and the input terminal of N type switch tube Q is collector, and the output end of N type switch tube Q is emitter.When N type switch tube Q is
When NMOS, the control terminal of N type switch tube Q is grid, and the input terminal of N type switch tube Q is drain electrode, and the output end of N type switch tube Q is
Source electrode.Wherein, the relatively small NMOS of preferred drive current.
The operation principle of the interface circuit of the two-wire system fieldbus is as follows：
When not accessing bus power source, adjustable precise parallel regulator U and N type switch tube Q are in cut-off state；Ginseng
Examine the sum of the pressure drop that the voltage difference between the Ref and anode A node of end is equal on first resistor R1 and second resistance R2；
When the DC operation state of the interface circuit is established, AC modulated signals zero, that is to say, that the second electricity
The pressure drop hindered on R2 is zero, and the voltage difference between the reference edge Ref and anode A node of adjustable precise parallel regulator U is just at this time
Equal to the pressure drop on first resistor R1；
At the same time, bus power source voltage is transmitted to the control terminal of N type switch tube Q by biasing circuit Bias, and N-type is made to open
Close pipe Q conductings；After N type switch tube Q conducting, just having electric current and flowing through first resistor R1 makes the pressure drop on first resistor R1 increase,
Until when increasing to above the reference voltage of adjustable precise parallel regulator U, adjustable precise parallel regulator U will be led
It is logical；After the U conductings of adjustable precise parallel regulator, the control terminal voltage (electric current) of N type switch tube Q can be made to reduce, then described
The DC current that interface circuit is drawn from bus will accordingly reduce, and the pressure drop on first resistor R1 can also decrease；
Finally, this negative feedback process can be such that the pressure drop on first resistor R1 stablizes in adjustable precise parallel regulator U
Reference voltage, the DC current size which draws from bus is the reference voltage and first resistor R1
The ratio between resistance value.
When needing to send out communication signal to bus, since the topological structure of the interface circuit meets profound and negative feedbck,
Voltage difference between reference edge Ref and anode A node is stablized in the reference voltage, and the impedance of reference edge Ref is very big, therefore believes
The alternating current of number processing circuit P outputs can all flow through second resistance R2；
Since the sum of the pressure drop on first resistor R1 and second resistance R2 is equal to the electricity between reference edge Ref and anode A node
Pressure difference is constant all the time, then, if the alternating voltage on second resistance R2 is Δ V, the alternating voltage on first resistor R1 is just
For-Δ V.If the alternating current of signal processing circuit P outputs is Δ i, the bus modulation electric current being modulated in bus is Δ I, that
Necessarily there are Δ i*R2=- Δ I*R1, to which the ratio of R1 and R2 only need to rationally be arranged, so that it may to realize smaller alternation
Current-modulation is that sizeable bus modulates electric current.
In addition, the embodiment of the invention also discloses a kind of two-wire system fieldbus, including two-wire system fieldbus ontology with
And the interface circuit being connected with the two-wire system fieldbus ontology, wherein the interface circuit can be used disclosed above
Any interface circuit.
Wherein, the two-wire system fieldbus ontology can be FF bus types, can also be Profibus-PA bus types
Type does not limit to.
In conclusion turn-on and turn-off of the present invention by closed-loop control adjustable precise parallel regulator, make its anode
Kept constant with reference to the voltage difference between pole, then for be serially connected in the anode and with reference to two resistance between pole and
Speech only need to rationally adjust this due to the alternating current of its circulate respectively bus modulation electric current and signal processing circuit output
The ratio of two resistance, so that it may modulate electric current so that the alternating current is modulated to sizeable bus.Compared to existing skill
Art, the present invention use closed-loop control, are influenced by extraneous factors such as temperature smaller, and its closed-loop is smaller, is easy to stablize, convenient
Production and debugging, furthermore its device usage quantity is few, and circuit structure is simple.
Each embodiment is described by the way of progressive in this specification, the highlights of each of the examples are with other
The difference of embodiment, just to refer each other for identical similar portion between each embodiment.
The foregoing description of the disclosed embodiments enables those skilled in the art to implement or use the present invention.
Various modifications to these embodiments will be apparent to those skilled in the art, as defined herein
General Principle can be realized in other embodiments without departing from the spirit or scope of the present invention.Therefore, of the invention
It is not intended to be limited to the embodiments shown herein, and is to fit to and the principles and novel features disclosed herein phase one
The widest range caused.
Claims (10)
1. a kind of interface circuit of two-wire system fieldbus, which is characterized in that opened including adjustable precise parallel regulator, N-type
Guan Guan, biasing circuit, first resistor and second resistance, wherein：
The adjustable precise parallel regulator is the three terminal device for having reference edge, cathode and anode, and cathode is through described inclined
Circuits connect the anode of bus power source, and anode connects the positive input terminal of signal processing circuit, with reference to the termination signal processing
The output end of circuit；
The negative input of the signal processing circuit terminates the cathode of the bus power source；
The control of the N type switch tube terminates the cathode of the adjustable precise parallel regulator, and input terminates the bus
The anode of power supply, output end connect the positive input terminal of the signal processing circuit through the first resistor；
The second resistance connects the output end of the reference edge and the N type switch tube of the adjustable precise parallel regulator.
2. interface circuit according to claim 1, which is characterized in that the biasing circuit is resistance.
3. interface circuit according to claim 1, which is characterized in that the model of the adjustable precise parallel regulator
LMV431。
4. interface circuit according to claim 1, which is characterized in that the model of the adjustable precise parallel regulator
TL431。
5. interface circuit according to claim 1, which is characterized in that the N type switch tube is NMOS tube.
6. interface circuit according to claim 1, which is characterized in that the N type switch tube is NPN type triode.
7. interface circuit according to claim 1, which is characterized in that the N type switch tube is N-type Darlington transistor.
8. a kind of two-wire system fieldbus, including two-wire system fieldbus ontology and with the two-wire system fieldbus ontology phase
The interface circuit of connection, which is characterized in that the interface circuit is the interface circuit described in any one of claim 1-7.
9. two-wire system fieldbus according to claim 8, which is characterized in that the two-wire system fieldbus ontology is FF
Bus type.
10. two-wire system fieldbus according to claim 8, which is characterized in that the two-wire system fieldbus ontology is
Profibus-PA bus types.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN201410849971.3A CN104660249B (en) | 2014-12-31 | 2014-12-31 | Two-wire system fieldbus and its interface circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410849971.3A CN104660249B (en) | 2014-12-31 | 2014-12-31 | Two-wire system fieldbus and its interface circuit |
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| CN104660249A CN104660249A (en) | 2015-05-27 |
| CN104660249B true CN104660249B (en) | 2018-09-18 |
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Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN110568901B (en) * | 2019-08-08 | 2020-11-20 | 浙江中控技术股份有限公司 | Device for connecting traditional industrial instrument to foundation field bus system |
| CN113271244B (en) * | 2021-04-09 | 2022-06-28 | 电子科技大学 | RS485 bus ad hoc network full-duplex communication system and automatic address addressing method thereof |
Citations (3)
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|---|---|---|---|---|
| CN202238482U (en) * | 2011-09-02 | 2012-05-30 | 杨义根 | Ultrasonic atomizer |
| WO2013001577A1 (en) * | 2011-06-29 | 2013-01-03 | 富士電機株式会社 | Interface circuit for fieldbus feed apparatus |
| CN104200587A (en) * | 2014-07-30 | 2014-12-10 | 浙江大学 | System and method for detecting outdoor wireless intrusion |
-
2014
- 2014-12-31 CN CN201410849971.3A patent/CN104660249B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2013001577A1 (en) * | 2011-06-29 | 2013-01-03 | 富士電機株式会社 | Interface circuit for fieldbus feed apparatus |
| CN202238482U (en) * | 2011-09-02 | 2012-05-30 | 杨义根 | Ultrasonic atomizer |
| CN104200587A (en) * | 2014-07-30 | 2014-12-10 | 浙江大学 | System and method for detecting outdoor wireless intrusion |
Non-Patent Citations (1)
| Title |
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| TL431型可调式精密并联稳压器及其应用;沙占有等;《集成电路应用》;20010831(第4期);第1段，第3节，图6 * |
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