CN207691822U - Bi-directional digital communication system based on 4-20mA electric current loops - Google Patents
Bi-directional digital communication system based on 4-20mA electric current loops Download PDFInfo
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- CN207691822U CN207691822U CN201820068506.XU CN201820068506U CN207691822U CN 207691822 U CN207691822 U CN 207691822U CN 201820068506 U CN201820068506 U CN 201820068506U CN 207691822 U CN207691822 U CN 207691822U
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Abstract
The utility model discloses a kind of bi-directional digital communication systems based on 4 20mA electric current loops, including host and equipment, the control circuit of host sending end is connect with the control circuit of the equipment receiving terminal, and the control circuit of equipment transmitting terminal is connect with the control circuit of host receiving terminal.In the utility model, by the basis of 4 20mA electric current loops, realizing bi-directional digital communication in a time multiplexed way, using effect is good, and at low cost, is easy to be widely popularized.
Description
Technical field
The utility model belongs to a kind of communication field in fire-fighting, more particularly to a kind of two-way number based on 4-20mA electric current loops
Word communication system.
Background technology
It is 4-20mA electric current loop techniques in a kind of communication modes that fire-fighting domain generally uses, but the technology is only supported a little pair
Point one-way communication.Although there is the HART technologies for realizing bi-directional digital communication in a manner of frequency division multiplexing based on 4-20mA in industry,
HART device costs are high, and therefore, it is difficult to large-scale application is unfolded.
A kind of 4-20MA standards of oil field flow instrument are disclosed in the documents of Patent No. 201520173613.5
Signal output apparatus, belongs to oil field special flow meter electronics technical field, which includes microcontroller, 13 resistance, seven
A capacitance, an optocoupler, a controllable accurate source of stable pressure, an operational amplifier, a MOS field-effect transistor and one are steady
Diode, the circuit is pressed, come the output of 4-20MA signals, to not only increase signal output by microprocessor output pwm signal
Efficiency simplifies peripheral circuit, also saves the cost of output par, c；Circuit signal output is stablized, precision is high, anti-interference energy
Power is strong, and uninterrupted dependable performance will not generate radiation and Conduction Interference to other equipment again simultaneously；The circuit is used for flow instrument
Signal output, have many advantages, such as that transient response is fast, electromagnetic compatibility is good, output signal accuracy is high, instrument can be met well
Instrumentation standard signal exports demand.
But without reference toA kind of communication field in fire-fighting.
Utility model content
To solve the above problems, the purpose of this utility model is to provide one kind realizing bi-directional digital in a time multiplexed way
The bi-directional digital communication system based on 4-20mA electric current loops of communication；
Another of the utility model is designed to provide a kind of bi-directional digital communication system based on 4-20mA electric current loops,
The bi-directional digital mechanics of communication is simple in structure, and using effect is good, at low cost, is easy to be widely popularized.
To achieve the above object, the technical solution of the utility model is as follows.
The utility model provides a kind of bi-directional digital communication system based on 4-20mA electric current loops, including host and equipment,
The control circuit of the host sending end is connect with the control circuit of the equipment receiving terminal, the control electricity of the equipment transmitting terminal
Road is connect with the control circuit of the host receiving terminal.In the utility model, host side increases a switching circuit, needs
When switching to digital communication, " electric current loop open circuit " failure is produced by switching circuit, being used in combination the TXD pins of UART port to control should
Switching signal.Host side increases current signal and turns digital signal circuit, and when >=16mA exports 1, and when≤12mA exports 0.From generator terminal
Increase open detection circuit, and the output of this circuit is connected to the RXD pins of UART port.Slave transmitting terminal passes through analog switch
VI circuit input ends are connected to DAC output ends and the TXD pins of UART port.When host sends order, it can directly pass through UART
Mouth output, slave receiving terminal can be received directly by UART；Slave send when, analog switch switches to TXD pins, by signal with
Current forms export, and host side is directly received after IV circuits by UART port.By on the basis of 4-20mA electric current loops, with when
Multiplex mode is divided to realize bi-directional digital communication, using effect is good, and at low cost, is easy to be widely popularized.
Further, the control circuit of the host sending end include the first diode, first resistor, the first metal-oxide-semiconductor,
Second resistance, the first triode, 3rd resistor, the first capacitance, the second capacitance, third capacitance, the 4th capacitance and inductance, described
One resistance one terminates TXD, and the other end is connect with the base stage of first triode, the emitter ground connection of first triode,
One end of the second resistance is connect with the collector of first triode, and the grid of the other end and first metal-oxide-semiconductor connects
It connects, the other end of the 3rd resistor is connect with one end of first diode, described 3rd resistor one end and described and institute
Second resistance connection is stated, the other end is connect with the source electrode of first metal-oxide-semiconductor, second diode, the first capacitance, the second electricity
Appearance, third capacitance and the 4th capacitance are in parallel successively, and one end common end grounding, and the drain electrode of the other end and first metal-oxide-semiconductor connects
It connects, the inductance connection is between the second capacitance and third capacitance common end.Host exports letter by the TXD pins of UART interface
Number, when which is 1, electric current loop conducting, normal work；When being 0, electric current loop open circuit simulates an open fault.
Further, the control circuit of the equipment receiving terminal includes the second triode, the 4th resistance, the 5th resistance, the
Six resistance, the 7th resistance, the 8th resistance, the 9th resistance, third diode, the 4th diode, the 5th diode and the 5th capacitance,
Second triode, the 5th resistance, third diode, the 8th resistance, the 9th resistance and the 5th capacitance are sequentially connected in series, and described
The collector of two triodes is connect with the 4th resistance, and the collector of second triode connects RXD, second triode
Base stage connect with one end of the 5th resistance, the 6th resistance is located at the public of the 5th resistance and third diode
End, and be grounded, the 4th diode and the 5th Diode series, and one end is connected to third diode and the 8th resistance
Common end, other end ground connection, described 7th resistance one end is connected to the public of the third diode and the 8th resistance
End, other end ground connection, described 9th resistance one end are connect with the 8th resistance, and the other end is connect with one end of the 5th capacitance, and the
The other end of five capacitances is grounded.In equipment end, electric current loop signal line-to-earth voltage, when electric current loop is normal, line voltage signal are detected
No more than 5V, when electric current loop is opened a way, the voltage is close to 24V, therefore, after being divided to line voltage signal, drives a NPN type
Triode, then when electric current loop is opened a way, triode ON, otherwise output signal 0 is 1, the number letter at lucky corresponding host end
Number output.
Further, the control circuit of the equipment transmitting terminal includes the tenth resistance, 11 resistance, 12 resistance,
13 resistance, the 14th resistance, the 15th resistance, the 16th resistance, the 17th resistance, the 18th resistance, the 19th resistance,
Six capacitances, the 7th capacitance, the 8th capacitance, the 9th capacitance, third transistor, the second metal-oxide-semiconductor, analog switch chip and electric current output
One end of chip, the tenth resistance is connect with the third interface of the analog switch chip, another termination TXD, and described 11
Resistance one end is located between the third interface and the tenth resistance of the analog switch chip, and the other end is grounded, the mould
The first interface of quasi- switch chip is signal output end, and the 5th interface of the analog switch chip connects 5V power supplys, the described tenth
One end of two resistance is connect with the 6th interface of the analog switch chip, and the other end is connect with ON, the analog switch chip
Second interface ground connection, the 4th interface of the analog switch chip pass through thirteenth resistor and the electric current pio chip the
Six interfaces connect, and described 14th resistance one end is connected to the 4th interface of the analog switch chip and the thirteenth resistor
Between, and the other end is grounded, described 15th resistance one end is connect with the 7th interface of the electric current pio chip, another termination
Ground, the tenth interfacing ground of the electric current pio chip, described 16th resistance one end and the 6th of the electric current pio chip
Interface connects, and other end ground connection, the 17th resistance is connected to the 4th interface and the 5th interface of the electric current pio chip
Between, described 6th capacitance one end is connect with the 5th interface of the electric current pio chip, other end ground connection, the 8th capacitance
One end is connected to the first interface of the electric current pio chip, and the 9th interface of the other end, the 9th of the electric current pio chip connects
Mouth is ground terminal, and described 7th capacitance one end is connect with the first interface of the electric current pio chip, the other end and described second
The grid of metal-oxide-semiconductor connects, and the second interface of the electric current pio chip is connected to the source of the metal-oxide-semiconductor by the 18th resistance
The drain electrode of pole, the metal-oxide-semiconductor connects the 19th resistance, and the 9th capacitance one terminates the drain electrode of the metal-oxide-semiconductor, and the other end is grounded,
The emitter of the third transistor meets the second interface of the electric current pio chip, the collector of the third transistor and institute
The grid connection of metal-oxide-semiconductor is stated, the base stage of the third transistor is connect with the source electrode of the metal-oxide-semiconductor.In equipment end, need to send
When digital signal, VI circuit input ends are switched to the TXD pins of UART interface by analog switch BL1551 so that send 1
When, electric current loop output >=16mA, when sending 0, electric current loop output≤12mA.
Further, the control circuit of the host receiving terminal includes the 20th resistance, the 4th triode, the 21st
20th resistance, the four or three described in resistance, the 22nd resistance, the 23rd resistance, the 24th resistance and the 5th triode
Pole pipe, the 21st resistance, the 5th triode and the 24th resistance are sequentially connected in series, and the collector of the 4th triode connects
RXD, the 20th resistance one terminate 5V voltages, the collector of the 4th triode of another termination, the hair of the 4th triode
Emitter grounding, the 22nd resistance one terminate 5V voltages, the collector of the 5th triode of another termination, the five or three pole
The emitter of pipe is grounded, and one end of the 23rd resistance is connected to the base stage of the 5th triode and the 24th resistance
Between, another termination AD-SENSOR, and the 24th resistance other end is grounded.Host side is by IV circuit output signal lists
It is solely handled, is converted into digital signal, and by adjusting the ratio of divider resistance so that output 1 is corresponded to when electric current >=16mA,
Output 0 is corresponded to when electric current≤12mA.
The advantage of the utility model is：Compared with the prior art, in the utility model, host side increases by one and opens
Powered-down road when needing to switch to digital communication, produces " electric current loop open circuit " failure by switching circuit, UART port is used in combination
TXD pins control the switching signal.Host side increases current signal and turns digital signal circuit, and when >=16mA exports 1, when≤12mA
Output 0.Increase open detection circuit from generator terminal, and the output of this circuit is connected to the RXD pins of UART port.Slave transmitting terminal
VI circuit input ends are connected to DAC output ends and the TXD pins of UART port by analog switch.It, can when host sends order
It is directly exported by UART port, slave receiving terminal can be received directly by UART；When slave is sent, analog switch switches to TXD
Pin exports signal as an electrical current, and host side is directly received after IV circuits by UART port.By in 4-20mA electric currents
On the basis of ring, bi-directional digital communication is realized in a time multiplexed way, using effect is good, and at low cost, is easy to be widely popularized.
Description of the drawings
Fig. 1 is the structure diagram of bi-directional digital communication system of the utility model based on 4-20mA electric current loops；
Fig. 2 is the control electricity of host sending end in bi-directional digital communication system of the utility model based on 4-20mA electric current loops
The circuit diagram on road.
Fig. 3 is the control electricity of equipment transmitting terminal in bi-directional digital communication system of the utility model based on 4-20mA electric current loops
The circuit diagram on road.
Fig. 4 is the control electricity of equipment receiving terminal in bi-directional digital communication system of the utility model based on 4-20mA electric current loops
The circuit diagram on road.
Fig. 5 is the control electricity of host receiving terminal in bi-directional digital communication system of the utility model based on 4-20mA electric current loops
The circuit diagram on road.
Specific implementation mode
In order to make the purpose of the utility model, technical solutions and advantages more clearly understood, below in conjunction with attached drawing and implementation
Example, the present invention will be further described in detail.It should be appreciated that specific embodiment described herein is only used to explain
The utility model is not used to limit the utility model.
To achieve the above object, the technical solution of the utility model is as follows.
Referring to shown in Fig. 1-5, the utility model provides a kind of bi-directional digital communication system based on 4-20mA electric current loops, packet
Host and equipment are included, the control circuit of the host sending end is connect with the control circuit of the equipment receiving terminal, the equipment
The control circuit of transmitting terminal is connect with the control circuit of the host receiving terminal.Host side increases a switching circuit, needs to cut
When shifting to digital communication, " electric current loop open circuit " failure is produced by switching circuit, is used in combination the TXD pins of UART port to control this and opens
OFF signal.Host side increases current signal and turns digital signal circuit, and when >=16mA exports 1, and when≤12mA exports 0.Increase from generator terminal
Alignment detection circuit is increased, and the output of this circuit is connected to the RXD pins of UART port.Slave transmitting terminal will by analog switch
VI circuit input ends are connected to DAC output ends and the TXD pins of UART port.When host sends order, it can directly pass through UART port
Output, slave receiving terminal can be received directly by UART；When slave is sent, analog switch switches to TXD pins, by signal with electricity
Manifold formula exports, and host side is directly received after IV circuits by UART port.By on the basis of 4-20mA electric current loops, with the time-division
Multiplex mode realizes bi-directional digital communication, and using effect is good, and at low cost, is easy to be widely popularized.
According to Fig.2, the control circuit of host sending end includes the first diode BZT5C15V, the second diode
SMBJ36A, first resistor R73, the first metal-oxide-semiconductor ZXMP10A13F, second resistance R75, the first triode Q8,3rd resistor R74,
First capacitance C45, the second capacitance C46, third capacitance C38, the 4th capacitance C39 and inductance L4, first resistor R73 mono- terminate TXD,
The other end is connect with the base stage of the first triode Q8, the emitter of the first triode Q8 ground connection, one end of second resistance R75 and the
The collector of one triode Q8 connects, and the other end is connect with the grid of the first metal-oxide-semiconductor ZXMP10A13F, and 3rd resistor R74's is another
One end is connect with one end of the first diode BZT5C15V, and the one end 3rd resistor R74 is connect with second resistance R75, the other end with
The source electrode of first metal-oxide-semiconductor ZXMP10A13F connects, the second diode SMBJ36A, the first capacitance C45, the second capacitance C46, third
Capacitance C38 and the 4th capacitance C39 are in parallel successively, and one end common end grounding, the leakage of the other end and the first metal-oxide-semiconductor ZXMP10A13F
Pole connects, and inductance L4 is connected between the second capacitance C46 and the common ends third capacitance C38.Host is drawn by the TXD of UART interface
Foot output signal, when which is 1, electric current loop conducting, normal work；When being 0, electric current loop open circuit simulates an open fault.
According to Fig.4, the control circuit of equipment receiving terminal includes the second triode WMBT3904, the 4th resistance R28, the
Five resistance R29, the 6th resistance R27, the 7th resistance R26, the 8th resistance R25, the 9th resistance R915, third diode SS14,
Four diode SMAJ50A, the 5th diode SMAJ50A and the 5th capacitance C6, the second triode WMBT3904, the 5th resistance R29,
Third diode SS14, the 8th resistance R25, the 9th resistance R915 and the 5th capacitance C6 are sequentially connected in series, the second triode
The collector of WMBT3904 is connect with the 4th resistance R28, and the collector of the second triode WMBT3904 connects RXD, the second triode
The base stage of WMBT3904 is connect with one end of the 5th resistance R29, and the 6th resistance R27 is located at the 5th resistance R29 and third diode
The common end of SS14, and be grounded, the 4th diode SMAJ50A connects with the 5th diode SMAJ50A, and one end is connected to third
The common end of diode SS14 and the 8th resistance R25, other end ground connection, the 7th one end resistance R26 is connected to third diode
The common end of SS14 and the 8th resistance R25, other end ground connection, the 9th one end resistance R915 are connect with the 8th resistance R25, the other end
It is connect with one end of the 5th capacitance C6, and the other end ground connection of the 5th capacitance C6.In equipment end, detection electric current loop signal wire is over the ground
Voltage, when electric current loop is normal, line voltage signal is no more than 5V, and when electric current loop is opened a way, the voltage is close to 24V, therefore, to signal wire
After voltage is divided, a NPN type triode is driven, then when electric current loop is opened a way, triode ON, output signal 0 is no
It is then 1, the digital signal at lucky corresponding host end exports.
According to Fig.3, the control circuit of equipment transmitting terminal includes the tenth resistance R34,11 resistance R35,12 electricity
Hinder R30, thirteenth resistor R10, the 14th resistance R12, the 15th resistance R11, the 16th resistance R13, the 17th resistance R14,
18th resistance R8, the 19th resistance R915, the 6th capacitance C7, the 7th capacitance C8, the 8th capacitance C9, the 9th capacitance C6, third
Triode Q2, the second metal-oxide-semiconductor BSP170P, analog switch chip BL1551 and electric current pio chip XTR111, the tenth resistance R34
One end connect with the third interface of analog switch chip BL1551, another termination TXD, 11 one end resistance R35 be located at simulation
Between the third interface and the tenth resistance R34 of switch chip BL1551, and the other end is grounded, and the of analog switch chip BL1551
One interface is signal output end, and the 5th interface of analog switch chip BL1551 connects 5V power supplys, one end of twelfth resistor R30 with
The 6th interface of analog switch chip BL1551 connects, and the other end is connect with ON, the second interface of analog switch chip BL1551
4th interface of ground connection, analog switch chip BL1551 passes through the 6th of thirteenth resistor R10 and electric current pio chip XTR111
Interface connects, the 14th one end resistance R12 be connected to the 4th interface of analog switch chip BL1551 and thirteenth resistor R10 it
Between, and the other end is grounded, the 15th one end resistance R11 is connect with the 7th interface of electric current pio chip XTR111, another termination
Ground, the tenth interfacing ground of electric current pio chip XTR111, the of the 16th one end resistance R13 and electric current pio chip XTR111
Six interfaces connect, other end ground connection, the 17th resistance R14 be connected to the 4th interface of electric current pio chip XTR111 with the 5th
Between interface, the 6th one end capacitance C7 is connect with the 5th interface of electric current pio chip XTR111, other end ground connection, the 8th capacitance
The one end C9 is connected to the first interface of electric current pio chip XTR111, the 9th interface of the other end, electric current pio chip XTR111's
9th interface is ground terminal, and the 7th one end capacitance C8 connect with the first interface of electric current pio chip XTR111, the other end and the
The grid of two metal-oxide-semiconductor BSP170P connects, and the second interface of electric current pio chip XTR111 is connected to the by the 18th resistance R8
The drain electrode of the source electrode of two metal-oxide-semiconductor BSP170P, the second metal-oxide-semiconductor BSP170P connects the 19th resistance R915, the 9th capacitance C6 mono- terminations
The drain electrode of second metal-oxide-semiconductor BSP170P, other end ground connection, the emitter of third transistor Q2 connect electric current pio chip XTR111's
Second interface, the collector of third transistor Q2 are connect with the grid of the second metal-oxide-semiconductor BSP170P, the base stage that third transistor is gone
It is connect with the source electrode of the second metal-oxide-semiconductor BSP170P.In equipment end, when needing to send digital signal, VI circuit input ends are passed through into mould
Quasi- switch BL1551 switches to the TXD pins of UART interface so that when sending 1, electric current loop output >=16mA, and when sending 0, electric current
Ring output≤12mA.
According to Fig.5, the control circuit of host receiving terminal includes the 20th resistance R79, the 4th triode Q11,
21 resistance R80, the 22nd resistance R78, the 23rd resistance R76, the 24th resistance R77 and the 5th triode Q10,
20th resistance R79, the 4th triode Q11, the 21st resistance R80, the 5th triode Q10 and the 24th resistance R77 according to
The collector of secondary series connection, the 4th triode Q11 meets RXD, and the 20th resistance R79 mono- terminates 5V voltages, the four or three pole of another termination
The collector of pipe Q11, the emitter ground connection of the 4th triode Q11, the 22nd resistance R78 mono- terminate 5V voltages, another termination
The collector of 5th triode Q10, the emitter ground connection of the 5th triode Q10, mono- ends the 23rd resistance R76 are connected to the five or three
Between the base stage of pole pipe Q10 and the 24th resistance R77, another termination AD-SENSOR, and the 24th resistance R77 other ends
Ground connection.Host side individually handles IV circuit output signals, is converted into digital signal, and by adjusting the ratio of divider resistance
Example so that correspond to output 1 when electric current >=16mA, output 0 is corresponded to when electric current≤12mA.
The advantage of the utility model is：Compared with the prior art, in the utility model, host side increases by one and opens
Powered-down road when needing to switch to digital communication, produces " electric current loop open circuit " failure by switching circuit, UART port is used in combination
TXD pins control the switching signal.Host side increases current signal and turns digital signal circuit, and when >=16mA exports 1, when≤12mA
Output 0.Increase open detection circuit from generator terminal, and the output of this circuit is connected to the RXD pins of UART port.Slave transmitting terminal
VI circuit input ends are connected to DAC output ends and the TXD pins of UART port by analog switch.It, can when host sends order
It is directly exported by UART port, slave receiving terminal can be received directly by UART；When slave is sent, analog switch switches to TXD
Pin exports signal as an electrical current, and host side is directly received after IV circuits by UART port.By in 4-20mA electric currents
On the basis of ring, bi-directional digital communication is realized in a time multiplexed way, using effect is good, and at low cost, is easy to be widely popularized.
The above is only the preferred embodiments of the present utility model only, is not intended to limit the utility model, all in this practicality
All any modification, equivalent and improvement etc., should be included in the guarantor of the utility model made by within novel spirit and principle
Within the scope of shield.
Claims (5)
1. a kind of bi-directional digital communication system based on 4-20mA electric current loops, including host and equipment, it is characterised in that the master
The control circuit of machine transmitting terminal is connect with the control circuit of the equipment receiving terminal, the control circuit of the equipment transmitting terminal and institute
State the control circuit connection of host receiving terminal.
2. the bi-directional digital communication system based on 4-20mA electric current loops as described in claim 1, which is characterized in that the host
The control circuit of transmitting terminal includes the first diode, the second diode, first resistor, the first metal-oxide-semiconductor, second resistance, first
Triode, 3rd resistor, the first capacitance, the second capacitance, third capacitance, the 4th capacitance and inductance, the first resistor one terminate
TXD, the other end are connect with the base stage of first triode, the emitter ground connection of first triode, the second resistance
One end connect with the collector of first triode, the other end is connect with the grid of first metal-oxide-semiconductor, third electricity
The other end of resistance is connect with one end of first diode, and described 3rd resistor one end connects with described with the second resistance
It connects, the other end is connect with the source electrode of first metal-oxide-semiconductor, second diode, the first capacitance, the second capacitance, third capacitance
It is in parallel successively with the 4th capacitance, and one end common end grounding, the other end are connect with the drain electrode of first metal-oxide-semiconductor, the inductance
It is connected between the second capacitance and third capacitance common end.
3. the bi-directional digital communication system based on 4-20mA electric current loops as described in claim 1, which is characterized in that the equipment
The control circuit of receiving terminal include the second triode, the 4th resistance, the 5th resistance, the 6th resistance, the 7th resistance, the 8th resistance,
9th resistance, third diode, the 4th diode, the 5th diode and the 5th capacitance, second triode, the 5th resistance,
Third diode, the 8th resistance, the 9th resistance and the 5th capacitance are sequentially connected in series, the collector of second triode and described the
Four resistance connect, and the collector of second triode connects RXD, the base stage of second triode and the one of the 5th resistance
End connection, the 6th resistance is located at the common end of the 5th resistance and third diode, and is grounded, the 4th diode
With the 5th Diode series, and one end is connected to the common end of third diode and the 8th resistance, other end ground connection, described
7th resistance one end is connected to the common end of the third diode and the 8th resistance, other end ground connection, the 9th electricity
Resistance one end is connect with the 8th resistance, and the other end is connect with one end of the 5th capacitance, and the other end ground connection of the 5th capacitance.
4. the bi-directional digital communication system based on 4-20mA electric current loops as described in claim 1, which is characterized in that the equipment
The control circuit of transmitting terminal includes the tenth resistance, eleventh resistor, twelfth resistor, thirteenth resistor, the 14th resistance,
15 resistance, the 16th resistance, the 17th resistance, the 18th resistance, the 19th resistance, the 6th capacitance, the 7th capacitance, the 8th electricity
Appearance, the 9th capacitance, third transistor, the second metal-oxide-semiconductor, analog switch chip and electric current pio chip, the one of the tenth resistance
End is connect with the third interface of the analog switch chip, and another termination TXD, described eleventh resistor one end is located at the simulation
Between the third interface of switch chip and the tenth resistance, and the other end is grounded, the first interface of the analog switch chip
The 5th interface for signal output end, the analog switch chip connects 5V power supplys, one end of the twelfth resistor and the mould
The 6th interface connection of quasi- switch chip, the other end are connect with ON, the second interface ground connection of the analog switch chip, the mould
4th interface of quasi- switch chip is connect by thirteenth resistor with the 6th interface of the electric current pio chip, and the described 14th
Resistance one end is connected between the 4th interface of the analog switch chip and the thirteenth resistor, and the other end is grounded, institute
It states the 15th resistance one end to connect with the 7th interface of the electric current pio chip, other end ground connection, the electric current pio chip
The tenth interfacing ground, described 16th resistance one end connect with the 6th interface of the electric current pio chip, other end ground connection,
17th resistance is connected between the 4th interface and the 5th interface of the electric current pio chip, described 6th capacitance one end
It is connect with the 5th interface of the electric current pio chip, other end ground connection, it is defeated that described 8th capacitance one end is connected to the electric current
Go out the first interface of chip, the 9th interface of the 9th interface of the other end, the electric current pio chip is ground terminal, the 7th electricity
Hold one end to connect with the first interface of the electric current pio chip, the other end is connect with the grid of second metal-oxide-semiconductor, the electricity
The second interface of stream pio chip is connected to the source electrode of the metal-oxide-semiconductor by the 18th resistance, and the drain electrode of the metal-oxide-semiconductor connects the tenth
Nine resistance, the 9th capacitance one terminate the drain electrode of the metal-oxide-semiconductor, other end ground connection, and the emitter of the third transistor connects
The second interface of the electric current pio chip, the collector of the third transistor are connect with the grid of the metal-oxide-semiconductor, and described
The base stage of three triodes is connect with the source electrode of the metal-oxide-semiconductor.
5. the bi-directional digital communication system based on 4-20mA electric current loops as described in claim 1, which is characterized in that the host
The control circuit of receiving terminal includes the 20th resistance, the 4th triode, the 21st resistance, the 22nd resistance, the 20th
20th resistance, the 4th triode, the 21st resistance, the five or three described in three resistance, the 24th resistance and the 5th triode
Pole pipe and the 24th resistance are sequentially connected in series, and the collector of the 4th triode meets RXD, and the 20th resistance one terminates 5V
Voltage, the collector of the 4th triode of another termination, the emitter ground connection of the 4th triode, the 22nd resistance one
5V voltages are terminated, the emitter of the collector of the 5th triode of another termination, the 5th triode is grounded, and the described 23rd
One end of resistance is connected between the base stage and the 24th resistance of the 5th triode, another termination AD-SENSOR, and institute
State the 24th resistance other end ground connection.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201820068506.XU CN207691822U (en) | 2018-01-16 | 2018-01-16 | Bi-directional digital communication system based on 4-20mA electric current loops |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201820068506.XU CN207691822U (en) | 2018-01-16 | 2018-01-16 | Bi-directional digital communication system based on 4-20mA electric current loops |
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| CN112860514A (en) * | 2021-02-01 | 2021-05-28 | 深圳市科陆精密仪器有限公司 | Method, system and storage medium for identifying slave machine by host machine based on 4-20mA current loop |
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| CN112860514A (en) * | 2021-02-01 | 2021-05-28 | 深圳市科陆精密仪器有限公司 | Method, system and storage medium for identifying slave machine by host machine based on 4-20mA current loop |
| CN112860514B (en) * | 2021-02-01 | 2022-08-16 | 深圳市科陆精密仪器有限公司 | Method, system and storage medium for identifying slave machine by host machine based on 4-20mA current loop |
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