CN106533875A - RS485 line selector circuit - Google Patents
RS485 line selector circuit Download PDFInfo
- Publication number
- CN106533875A CN106533875A CN201611150758.9A CN201611150758A CN106533875A CN 106533875 A CN106533875 A CN 106533875A CN 201611150758 A CN201611150758 A CN 201611150758A CN 106533875 A CN106533875 A CN 106533875A
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- Prior art keywords
- circuit
- terminals
- jing
- resistance
- audion
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Classifications
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L12/00—Data switching networks
- H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
- H04L12/40—Bus networks
- H04L12/40006—Architecture of a communication node
- H04L12/40013—Details regarding a bus controller
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/38—Transceivers, i.e. devices in which transmitter and receiver form a structural unit and in which at least one part is used for functions of transmitting and receiving
- H04B1/40—Circuits
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L12/00—Data switching networks
- H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
- H04L12/40—Bus networks
- H04L12/40143—Bus networks involving priority mechanisms
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- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Electronic Switches (AREA)
Abstract
The invention relates to an RS485 line selector circuit. The RS485 line selector circuit comprises a signal detection circuit, an automatic delay circuit and a line switching execution circuit; the signal detection circuit is used for detecting a 485 signal sent by a host I; the RS485 terminal of the host I is accessed to the input end of the signal detection circuit; the signal detection circuit outputs a triggering signal; the triggering signal is accessed to the automatic delay circuit; the automatic delay circuit outputs a driving signal; the driving signal is accessed to the line switching execution circuit; and the output end of the line switching execution circuit controls the RS485 terminal of a meter to selectively connect between the RS485 terminal of the host I and the RS485 terminal of a host II. By means of the RS485 line selector circuit disclosed by the invention, the problem that a 485 bus has multiple hosts can be solved in a hardware manner; furthermore, the priority is provided; the host having the high priority can interrupt the host having the low priority to perform communication; the bus is automatically released after communication is completed; therefore, the RS485 line selector circuit disclosed by the invention has the advantages of being simple and reliable in structure, high in automation degree, automatic in bus segmentation and the like; and furthermore, the bus hosts can be selected according to the priorities.
Description
Technical field
The present invention relates to a kind of circuit for solving many main conflicts, and in particular to a kind of RS485 line selectors circuit.
Background technology
RS-485 buses as a kind of multinode, half-duplex, differential data transmission communication modes, due to its have it is long away from
The characteristics of suppressing from transmission, good common mode disturbances, is widely used in all kinds of centralized meter-reading systems.In certain applications occasion, always
Multiple main frames are there may be in line, when multi-host communication, are bound to produce conflict interference.Existing settling mode typically has two
Kind：One is that, by time-multiplexed method, different main frames is divided in different timeslices；Two be by collision detection-
Algorithm is avoided, multiple main frames take different timeslices by algorithm.Both the above solution is all by way of software
To solve many main conflicts, collision problem is not fundamentally solved.
The content of the invention
For the problems referred to above, the present invention provide it is a kind of by way of hardware solving many main conflicts in 485 buses, tie
The simple and reliable RS485 line selector circuits of structure.
For solving the above problems, the technical scheme that the present invention takes is：A kind of RS485 line selectors circuit, including use
The signal deteching circuit of 485 signals sent in detection main frame I, automatic time delay circuit and circuit switching execution circuit；Main frame I's
RS485 terminals access the input of signal deteching circuit, signal deteching circuit outfan output trigger；Trigger is accessed
The input of automatic time delay circuit, the outfan output drive signal of automatic time delay circuit, the switching of drive signal line attachment are held
The input of row circuit, circuit switching execution circuit outfan control meter RS485 terminals main frame I RS485 terminals and
Connection is selected between the RS485 terminals of main frame II.
When the main frame I of RS485 buses needs communication, the RS485 terminals of main frame I are connected with 485 terminal of meter；Otherwise
Main frame II RS485 terminals are connected with 485 terminal of meter.
Signal deteching circuit is responsible for detecting 485 signals that main frame I sends, and produces trigger for automatic time delay circuit.
After automatic time delay circuit receives the trigger of signal deteching circuit, the execution circuit of driver circuit switching immediately, and
Start timing, after the time delay specified is reached, cancel drive signal.
After circuit switching circuit receives drive signal, by the RS485 terminals of main frame I and 485 terminal short circuit of meter；Do not receive
During drive signal, by 485 terminals of RS of main frame II and 485 terminal short circuit of meter.
Described signal deteching circuit is such：The first RS485 terminals of main frame I and the 2nd RS485 terminals are connect respectively
To the B pins and A pins of non-polar 485 chip；The B pin Jing first resistors ground connection of non-polar 485 chip, nonpolarity 485 core
The A pin Jing second resistances of piece connect power supply；Non-polar 485 chip transmitting-receiving control foot, transmission foot are grounded, and receive foot Jing the 4th electric
Resistance connects the base stage of the first audion, and the first transistor emitter ground connection, the colelctor electrode Jing 3rd resistors of the first audion are pulled upward to
Power supply, the colelctor electrode of the first audion are connected with the grid of the first metal-oxide-semiconductor, the source ground of the first metal-oxide-semiconductor, the first metal-oxide-semiconductor
Drain electrode output trigger.485 signals are detected using non-polar 485 chip herein, for 485 polarity no requirement (NR)s, is reduced existing
The construction workload of field.
Described automatic time delay circuit is such：5th resistance, one termination power, the 6th resistance eutral grounding of one end, the 5th
The junction of resistance and the 6th resistance is connected to the inverting input of operational amplifier, and trigger is connected to the homophase of operational amplifier
Input, the homophase input of operational amplifier are terminated with constituting rc charging circuit by the 7th resistance and the first electric capacity；Computing is put
The 8th resistance of outfan Jing of big device is connected to the base stage of the second audion, the grounded emitter of the second audion, the second audion
Colelctor electrode output drive signal.
Described circuit switching execution circuit is such：The 9th resistance of drive signal Jing is pulled upward to power supply and Jing the tenth is electric
Resistance is connected to the base stage of the 3rd audion, the grounded emitter of the 3rd audion, the 11st resistance of colelctor electrode Jing of the 3rd audion
It is connected to the first level led negative pole of light coupling relay, just level led positive pole connects power supply, the first of main frame I
RS485 terminals and the two the first RS485 terminals are connected on the normally opened terminal of light coupling relay, RS485 terminals of main frame II
It is connected on the normally closed terminal of light coupling relay with the two the first RS485 terminals, meter RS485 terminals are connected to the public affairs of light coupling relay
Altogether on terminal.Real-time, the reliability of switching are improve as motion device using light coupling relay herein.
The A pins and B pins equal Jing moments of non-polar 485 chip suppress diode ground connection and the B of non-polar 485 chip draws
Foot Jing critesistor connects RS485 terminals of main frame I.Moment suppresses the protection electricity of diode and critesistor composition bus
Road, provides overvoltage, overcurrent protection for bus.
The present invention proposes a kind of 485 line selector circuit, solves 485 buses and there are multiple masters by way of hardware
The problem of machine, and priority is provided, the main frame of high priority can interrupt the main frame of low priority and be communicated, and communication is completed
After be automatically releasable bus.The present invention has simple and reliable for structure, high degree of automation, automatic splitted bus, selects by priority
The advantages of bus host.
Description of the drawings
Fig. 1 is signal deteching circuit schematic diagram；
Fig. 2 is automatic time delay circuit theory diagrams；
Fig. 3 is circuit switching execution circuit schematic diagram；
Specific embodiment
A kind of RS485 line selectors circuit, including for detect 485 signals that main frame I sends signal deteching circuit,
Automatic time delay circuit and circuit switching execution circuit；
As shown in figure 1, described signal deteching circuit is such：The first RS485 terminal RS485I_B Jing of main frame I are warm
Quick resistance connects the B pins of non-polar 485 chip U1, and the 2nd RS485 terminal RS485I_A of main frame I are respectively connected to nonpolarity 485
The A pins of chip U1；B pin Jing first resistors R1 of non-polar 485 chip U1, the first moment suppress diode TVS1 ground connection；
A pin Jing second resistances R2 of non-polar 485 chip U1 meet power vd D, while the second moments of Jing suppress diode TVS2 to be grounded；
Non-polar 485 chip U1 transmitting-receiving control feet, transmission foot are grounded, and make non-polar 485 chip U1 be in reception state all the time.Receive
The 4th resistance R4 of foot Jing connect the base stage of the first audion Q1, the first audion Q1 grounded emitters, the current collection of the first audion Q1
Pole Jing 3rd resistors R3 are pulled upward to power vd D, and the colelctor electrode of the first audion Q1 is connected with the grid of the first metal-oxide-semiconductor M1, and first
The source ground of metal-oxide-semiconductor M1, drain electrode output trigger RS485_T of the first metal-oxide-semiconductor M1.
When the RS485 terminals of main frame I send data, first have to send a low level start bit, nonpolarity 485 core
The reception foot of piece U1 is low level, and Jing the first audion Q1 are anti-phase, and the grid of the first metal-oxide-semiconductor M1 is high level, the first metal-oxide-semiconductor M1
It is in the conduction state, therefore trigger RS485_T is low level.Conversely, when the RS485 terminals of main frame I do not send data,
The reception foot of non-polar 485 chip U1 is high level, and Jing the first audion Q1 are anti-phase, and the grid of the first metal-oxide-semiconductor M1 is low level,
First metal-oxide-semiconductor M1 is in cut-off state, therefore trigger RS485_T is high resistant, and level height is depending on peripheral circuit.
As shown in Fig. 2 described automatic time delay circuit is such：5th resistance R5 mono- terminates power vd D, one end the
Six resistance R6 are grounded, voltage U on the basis of the junction voltage of the 5th resistance R5 and the 6th resistance R6refIt is connected to operational amplifier U2
Inverting input, trigger RS485_T is connected to the in-phase input end of operational amplifier U2, and the homophase of operational amplifier U2 is defeated
Enter to be terminated with to constitute rc charging circuit by the 7th resistance R7 and the first electric capacity C1；The outfan Jing the 8th of operational amplifier U2 is electric
Resistance R8 is connected to the base stage of the second audion Q2, the grounded emitter of the second audion Q2, the colelctor electrode output of the second audion Q2
Drive signal RS485_SE.When trigger RS485_T is low level, the electric charge of the first electric capacity C1 is given out light rapidly, computing
The anti-phase input terminal voltage of amplifier U2 is more than positive input voltage, operational amplifier U2 outfans output low level, Jing the
Eight resistance R8 are connected to the base stage of the second audion Q2, and the second audion Q2 is in cut-off state, and drive signal RS485_SE is height
Resistance, level height depend on peripheral circuit.Conversely, when trigger RS485_T is high resistant, level is pulled up by the 7th resistance R7
To power vd D, the level of trigger RS485_T is the charging voltage of the first electric capacity C1.When the voltage of the first electric capacity C1 is more than
Reference voltage UrefWhen, the anti-phase input terminal voltage of operational amplifier U2 is less than positive input voltage, operational amplifier U2 outputs
End output high level, the second audion Q2 are in the conduction state, and drive signal RS485_SE is low level.
As shown in figure 3, described circuit switching execution circuit is such：The 9th resistance R9 of drive signal RS485_SE Jing
It is pulled upward to the base stage that power vd D the tenth resistance R10 of Jing are connected to the 3rd audion Q3, the grounded emitter of the 3rd audion Q3,
The 11st resistance R11 of colelctor electrode Jing of the 3rd audion Q3 are connected to the first level led negative pole of light coupling relay RLY1,
Just level led positive pole meets power vd D, a RS485 terminals RS485I_B of main frame I and the two the first RS485 terminals
RS485I_A is connected on the normally opened terminal of light coupling relay RLY1, a RS485 terminals RS485II_B of main frame II and the two the
One RS485 terminal RS485II_A are connected on the normally closed terminal of light coupling relay RLY1, and meter RS485 terminals are connected to optocoupler relay
On the public terminal of device RLY1.
When drive signal RS485_SE is high resistant, due to the effect of pull-up resistor R9, the 3rd audion Q3 saturation conductions,
The primary LEDs ON of light coupling relay RLY1, the actuating of relay, by the RS485 terminals of main frame I and meter RS485 ends
Son is connected.Otherwise when drive signal RS485_SE is low level, the 3rd audion Q3 cut-offs, the primary of light coupling relay RLY1
Light emitting diode does not have electric current to enter, and relay is in default conditions, RS485 terminals and the meter RS485 terminal phases of main frame II
Even.
When the RS485 sides of main frame I send data, the RS485 terminals of main frame I are connected by circuit with meter RS485 terminals.
As long as main frame sends data, that is, send bus and send " 0 ", the level of the first electric capacity C1 in automatic time delay circuit will be set to
Zero, only after the RS485 sides of main frame I have sent data, i.e., bus is in disarmed state, and (t after continuing regular time t
=R7C1ln [VDD/ (VDD-Uref)]), i.e. the level of the first electric capacity C1 is charged to more than reference voltage by the 7th resistance R7
UrefWhen, the RS485 terminals of main frame II are connected with 485 terminal of meter.
Claims (5)
1. a kind of RS485 line selectors circuit, it is characterised in that：Including for detecting the signal of 485 signals that main frame I sends
Detection circuit, automatic time delay circuit and circuit switching execution circuit；The RS485 terminals of main frame I access the defeated of signal deteching circuit
Enter end, signal deteching circuit outfan output trigger (RS485_T)；Trigger (RS485_T) accesses automatic time delay electricity
The input on road, the outfan output drive signal (RS485_SE) of automatic time delay circuit, drive signal (RS485_SE) are accessed
The input of circuit switching execution circuit, the outfan of circuit switching execution circuit control meter RS485 terminals main frame I's
Connection is selected between the RS485 terminals of RS485 terminals and main frame II.
2. RS485 line selectors circuit according to claim 1, it is characterised in that described signal deteching circuit is this
Sample：The first RS485 terminals (RS485I_B) of main frame I and the 2nd RS485 terminals (RS485I_A) are respectively connected to nonpolarity 485
The B pins and A pins of chip (U1)；B pins Jing first resistors (R1) ground connection of non-polar 485 chip (U1), nonpolarity 485 core
A pins Jing second resistances (R2) of piece (U1) connects power supply (VDD)；Non-polar 485 chip (U1) transmitting-receiving control foot, transmission foot connect
Ground, receives the base stage that the 4th resistance (R4) of foot Jing meets the first audion (Q1), the first audion (Q1) grounded emitter, and the one or three
Colelctor electrode Jing 3rd resistors (R3) of pole pipe (Q1) is pulled upward to power supply (VDD), the colelctor electrode of the first audion (Q1) and a MOS
The grid of pipe (M1) is connected, the source ground of the first metal-oxide-semiconductor (M1), the drain electrode output trigger of the first metal-oxide-semiconductor (M1)
(RS485_T)。
3. RS485 line selectors circuit according to claim 2, it is characterised in that：Described automatic time delay circuit is
It is such：5th resistance (R5) termination power (VDD), the 6th resistance (R6) of one end ground connection, the 5th resistance (R5) and the 6th
The junction of resistance (R6) is connected to the inverting input of operational amplifier (U2), and trigger (RS485_T) is connected to operation amplifier
The in-phase input end of device (U2), the homophase input of operational amplifier (U2) are terminated with by the 7th resistance (R7) and the first electric capacity (C1)
Composition rc charging circuit；The 8th resistance (R8) of outfan Jing of operational amplifier (U2) is connected to the base of the second audion (Q2)
Pole, the grounded emitter of the second audion (Q2), the colelctor electrode output drive signal (RS485_SE) of the second audion (Q2).
4. RS485 line selectors circuit according to claim 1, it is characterised in that：Described circuit switching performs electricity
Road is such：The 9th resistance (R9) of drive signal (RS485_SE) Jing is pulled upward to power supply (VDD) and the tenth resistance (R10) of Jing connects
To the base stage of the 3rd audion (Q3), the grounded emitter of the 3rd audion (Q3), the colelctor electrode Jing of the 3rd audion (Q3)
11 resistance (R11) are connected to the first level led negative pole of light coupling relay (RLY1), just level led positive pole
Connect power supply (VDD), RS485 terminals (RS485I_B) of main frame I and the two the first RS485 terminals (RS485I_A) are connected to light
On the normally opened terminal of coupling relay (RLY1), RS485 terminals (RS485II_B) of main frame II and the two the first RS485 ends
Sub (RS485II_A) is connected on the normally closed terminal of light coupling relay (RLY1), and meter RS485 terminals are connected to light coupling relay
(RLY1) on public terminal.
5. RS485 line selectors circuit according to claim 2, it is characterised in that：The A of non-polar 485 chip (U1)
Pin and B pins equal Jing moments suppress diode ground connection and the B pin Jing critesistor of non-polar 485 chip (U1) meets main frame I
RS485 terminals (RS485I_B).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201611150758.9A CN106533875A (en) | 2016-12-13 | 2016-12-13 | RS485 line selector circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201611150758.9A CN106533875A (en) | 2016-12-13 | 2016-12-13 | RS485 line selector circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN106533875A true CN106533875A (en) | 2017-03-22 |
Family
ID=58339338
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201611150758.9A Pending CN106533875A (en) | 2016-12-13 | 2016-12-13 | RS485 line selector circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN106533875A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107516411A (en) * | 2017-09-21 | 2017-12-26 | 长沙瑞斯康通信技术有限公司 | M bus kilowatt meter reading-out systems |
| CN114630241A (en) * | 2022-02-21 | 2022-06-14 | 国网山东省电力公司滨州供电公司 | Automatic audio reverse-standby device and using method |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1993000623A1 (en) * | 1991-06-28 | 1993-01-07 | Square D Company | Electrical distribution system with improved circuit for multiple circuit breaker control |
| US5249115A (en) * | 1991-06-28 | 1993-09-28 | Square D Company | Switch input termination array |
| CN2271729Y (en) * | 1996-12-25 | 1997-12-31 | 三明物产(北京)电子有限公司 | Optically coupled isolating multisequencing serial communication module |
| CN101398796A (en) * | 2007-09-30 | 2009-04-01 | 北京国通创安信息技术有限公司 | Multipath serial communication controller and multipath control method thereof |
| CN201570020U (en) * | 2009-12-30 | 2010-09-01 | 成都前锋电子电器集团股份有限公司 | Automatic switching circuit of 485 interface and series port |
| CN202795352U (en) * | 2012-05-10 | 2013-03-13 | 北京北变智达科技有限公司 | Wiring method for recommend standard (RS) 232 interface and RS 485 interface |
| CN206517431U (en) * | 2016-12-13 | 2017-09-22 | 国网山东省电力公司 | A kind of RS485 line selectors circuit |
-
2016
- 2016-12-13 CN CN201611150758.9A patent/CN106533875A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1993000623A1 (en) * | 1991-06-28 | 1993-01-07 | Square D Company | Electrical distribution system with improved circuit for multiple circuit breaker control |
| US5249115A (en) * | 1991-06-28 | 1993-09-28 | Square D Company | Switch input termination array |
| CN2271729Y (en) * | 1996-12-25 | 1997-12-31 | 三明物产(北京)电子有限公司 | Optically coupled isolating multisequencing serial communication module |
| CN101398796A (en) * | 2007-09-30 | 2009-04-01 | 北京国通创安信息技术有限公司 | Multipath serial communication controller and multipath control method thereof |
| CN201570020U (en) * | 2009-12-30 | 2010-09-01 | 成都前锋电子电器集团股份有限公司 | Automatic switching circuit of 485 interface and series port |
| CN202795352U (en) * | 2012-05-10 | 2013-03-13 | 北京北变智达科技有限公司 | Wiring method for recommend standard (RS) 232 interface and RS 485 interface |
| CN206517431U (en) * | 2016-12-13 | 2017-09-22 | 国网山东省电力公司 | A kind of RS485 line selectors circuit |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107516411A (en) * | 2017-09-21 | 2017-12-26 | 长沙瑞斯康通信技术有限公司 | M bus kilowatt meter reading-out systems |
| CN114630241A (en) * | 2022-02-21 | 2022-06-14 | 国网山东省电力公司滨州供电公司 | Automatic audio reverse-standby device and using method |
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Effective date of abandoning: 20221206 |