CN2271729Y - Optically coupled isolating multisequencing serial communication module - Google Patents
Optically coupled isolating multisequencing serial communication module Download PDFInfo
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- CN2271729Y CN2271729Y CN 96249258 CN96249258U CN2271729Y CN 2271729 Y CN2271729 Y CN 2271729Y CN 96249258 CN96249258 CN 96249258 CN 96249258 U CN96249258 U CN 96249258U CN 2271729 Y CN2271729 Y CN 2271729Y
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Abstract
The utility model relates to an electric current loop serial interface circuit module used in computer serial communication, which can realize the isolation between a communication line and each communication unit, complete semi-duplex communication between multiple communication units, and realize self-sending and self-receiving in communication. The module is connected between each communication unit and each communication line; the communication line comprises power supply, ground, and a signal transmission line. The module comprises a serial signal sending isolating and transforming circuit connected with a TXD, an electronic switch, a serial signal receiving isolating and transforming circuit connected with an RXD, and a line current detecting circuit. The electronic switch is controlled by the communication unit, and the detecting circuit sends failure signals to the communication unit and turns off the electronic switch.
Description
The utility model relates to a kind of computer interface unit, relates to the electric current loop serial interface circuit module in a kind of singlechip serial communication or rather.
20mA current loop (hereinafter to be referred as electric current loop) serial line interface is a widely used interface circuit in a kind of computer serial communication.The structure of electric current loop serial communication interface as shown in Figure 1, by the transmission of computing machine 10 side RT+, send-connect and compose the 20mA output current loop with the reception amplifier load RL of terminal 20 sides or sensor and form by the 20mA input current loop of the reception ten of computing machine 10 side reception amplifier load RL, reception-connect and compose with terminal 20 side RT.When sending data,, make the loop form the switching state regularly, shown in K switch among the figure according to logical one, 0 state of control signal.
The great advantage of this electric current loop is that low-resistance transmission line is insensitive to electrical noise, is fit to long distance and transmits, and its shortcoming is: signal communication is point-to-point, can not accomplish multi computer communication; Can not guarantee that signal sends consistent with reception; There is not self-diagnostic function.
We often need to do multi computer communication in real work, the communication between promptly a plurality of single-chip microcomputers need constitute the networking with electric current loop, and will guarantee the accurate of data transmission, press for a kind of electric current loop serial interface circuit of redesign.
The purpose of this utility model is a kind of light-coupled isolation multilevel serial communication module of design, be connected between communication line and each communication unit, can realize the isolation between communication line and each communication unit and finish half duplex communication between a plurality of communication units, during real-time communication, can realize that internal loopback carries out self check between communication unit.
Light-coupled isolation multilevel serial communication module of the present utility model, the serial data that is connected in communication line and each communication unit sends, between receiving end, and communication line comprises a power lead, a ground wire and a signal transmssion line, it is characterized in that:
Described module sends isolated variable circuit, an electronic switch, serial signal reception isolated variable circuit and a line current testing circuit by a serial signal and connects and composes; Described serial signal sends the serial data transmitting terminal that the isolated variable circuit connects described communication unit, serial signal sends the output of isolated variable circuit and connects electronic switch signal input end and line current testing circuit input end, the signal output part of electronic switch connects described signal transmssion line and serial signal receives the isolated variable circuit input end, serial signal receives the serial data receiving end that the isolated variable circuit output end connects described communication unit, the switch control end of electronic switch is connected a control signal output ends of news unit, and line current testing circuit output terminal is connected a signal input end of news unit.
Described serial signal transmission isolated variable circuit is linked in sequence by transistor input switching circuit, photoelectric isolating circuit and VM0S single tube voltage controlled current circuit and constitutes.
Described serial signal receives the isolated variable circuit and is made of photoelectric isolating circuit connection voltage contrasting amplified circuit.
Described line current testing circuit is linked in sequence by current sampling circuit, voltage comparator, photoelectric isolating circuit and amplifying circuit and constitutes.
Described electronic switch is a relay circuit by transistor driving.
The power lead of described each module and signal transmssion line span are connected to pull-up resistor.
During initialization, the logic state of the control signal output ends that all communication units are connected with electronic switch controling end makes the electronic switch normally opened contact be in on-state, and signal transmssion line sends the isolated variable circuit and receives the isolated variable circuit with serial signal by electronic switch and serial signal and is connected; When line idle, the serial data transmitting terminal of all communication units is 1 level, serial signal sends the isolated variable circuit makes signal transmssion line keep level"1" by electronic switch, and the serial data receiving end that the high level of signal transmssion line makes serial signal receive the isolated variable circuit again keeps high level; When a certain communication unit will send, the high and low level state of its serial data transmitting terminal makes on the signal transmssion line level follow synchronous variation by electronic switch, and receive the isolated variable circuit by its serial signal and realize the internal loopback function by the serial data receiving end of communication unit, all the other communication units then are in accepting state, the level synchronization that the serial data receiving end of its serial signal reception isolated variable circuit is followed on the signal transmssion line changes, and realizes multilevel serial communication; When the line current testing circuit detects fault, in time pass through the signal input end notification communication unit of communication unit, normally closed contact by its control signal output ends order electronic switch disconnects rapidly, out of order communication unit and circuit are broken away from, to ensure the normal communication between all the other communication units.
Further specify technology of the present utility model below in conjunction with the embodiment accompanying drawing
Fig. 1 electric current loop serial communication interface structural representation
Fig. 2 light-coupled isolation multilevel serial communication module principle block diagram
Fig. 3 light-coupled isolation multilevel serial communication module electrical schematic diagram
Addressed before Fig. 1 illustrates and repeated no more.
Referring to Fig. 2, the structure of two communication modules shown in the figure and with being connected of circuit, each communication module is formed by four big functional parts, comprises that serial signal sends isolated variable circuit 50, electronic switch 40, serial signal reception isolated variable circuit 30 and netting twine current detection circuit 60.Wherein serial signal transmission isolated variable circuit 50 is linked in sequence by transistor input switching circuit 503, photoelectric isolating circuit 502 and VM0S single tube voltage controlled current circuit 501 and constitutes, serial signal receives isolated variable circuit 30 and is connected and composed by photoelectric isolating circuit 302 and voltage contrasting amplified circuit 301, and netting twine current detection circuit 60 is linked in sequence by current sampling circuit 601, voltage comparator 602, photoelectric isolating circuit 603 and amplifying circuit 604 and constitutes.
The TXD of each communication module, RXD, P1.1, P1.0 connect the end of the same name of corresponding communication unit single-chip microcomputer 70,80 respectively, the B end of each communication module links together by the B signal transmssion line, also have the power end of power lead and ground wire and each communication module in addition, the ground end connects (not shown).
Optical coupling isolation circuit is all adopted in the transmission of communication module, reception, has eliminated external interference effectively, has realized the isolation of communication line and each communication unit.Communication line adopts common triple cable, and cost is low, and it is convenient to lay, and can finish the half duplex communication between a plurality of communication units.During each communication unit real-time communication, can realize that internal loopback carries out self check, avoid the overshoot and the warfare of communicating circuit effectively, lay a good foundation for carrying out multi computer communication reliably.Experiment shows, during up to 0.01 microfarad, this communication line still can be worked reliably at the distributed capacitance of communication line.
Referring to Fig. 3, be the enforcement circuit diagram of each communication module, the triple cable of communication line is respectively A, B, COM, connects independently 12V direct supply between A and the C0M, and the A line connects power positive end, and the COM line connects power supply negative terminal.
Transistor V2 and peripheral cell thereof connect and compose the transistor input switching circuit, connect and compose serial signal and send isolated variable circuit 50 with photoelectricity coupling buffer circuit D4, VMOS pipe voltage controlled current circuit V1.
Transistor V3 and relay KR 1 connect and compose electronic switch 4D.
Photoelectricity coupling buffer circuit D2 and voltage contrasting amplified circuit D1:A etc. connect and compose serial signal and receive isolated variable circuit 30.
Current sampling resistor RB, voltage comparator D3:A, photoelectricity coupling buffer circuit D5 and amplifying circuit D1:B connect and compose netting twine current detection circuit 60.
During initialization, the P1.1 of all communication modules end is all exported high level, and the normal opened contact of relay KR 1 is connected.
When line idle, promptly the serial port transmitting terminal TXD of all communication units is high level, V2 ends, the light emitting diode no current of high speed photo coupling D4 flows through, its triode ends, and 5 pin of D4 are low level, and VMOS pipe V1 ends, the V1 source electrode is connected by the normally opened contact of relay KR 1 photoelectricity coupling buffer circuit D2 continuous with the B line and in the communication module, makes the B line be pulled to high level.
Because the B line is a high level, the light emitting diode no current that receives optocoupler D2 flows through, its triode ends, 6 pin of optocoupler D2 are high level, voltage comparator D1:A is used for signal shaping, its positive input terminal current potential is higher than the current potential of negative input end, so D1:A output is RXD, and communication unit serial port receiving end is a high level.
If certain communication unit will send data or order, all the other communication units can only be in accepting state.When the TXD end that sends communication unit is low level, the V2 conducting, the light emitting diode of high speed photo coupling D4 has electric current to flow through, its triode conducting, 5 pin of D4 are high level, the V1 conducting, the B line is pulled to low level state.Because the B line is a low level, the light emitting diode of D2 has electric current to flow through in this communication module and all the other communication modules, its triode conducting, the 6 pin output low levels of D2, the positive input terminal current potential of voltage comparator D1:A is lower than the negative input end current potential, it is low level that D1:A exports 1 pin, so the serial port receiving end RXD of all communication units is low level; When the TXD end that sends communication unit is high level, then as previously mentioned, V2 ends, 5 pin of B4 are low level, and V1 ends, and the B line is a high level, 6 pin of D2 are high level, D1:A exports high level, and the serial port receiving end RXD of all communication units is high level, has so finished the serial communication at whole networking.
If regulation is used address bit in the communications protocol, then can finish single function to single-pass news and broadcast communication.Because this communication module oneself oneself also can receive when sending, the data that receive can be compared with the data of transmission, if identical then continuation sends, if difference then stop to send, make communication network be in idle condition to wait the order of main frame, avoid the overshoot and the warfare of communicating circuit effectively, guaranteed the reliability of multi computer communication.
Detection when VMOS pipe V1 drain resistance R8 is used for the V1 fault, if V1 is in non-emission state, the last no current of R8 flows through, voltage comparator D3:A is output as high level, the 6 pin output high level of optocoupler D5, the 7 pin output high level of voltage comparator D1:B, the P1.0 end also is a high level; If V1 electric leakage surpasses 12mA, the pressure drop on the R8 is greater than normal value, voltage comparator D3:A output low level, and the 6 pin output low levels of optocoupler D5, the 7 pin output low levels of voltage comparator D1:B, P1.0 also is a low level.Therefore detect the level state of each communication unit P1.0, just can detect non-emission state,, just its P1.1 be become low level by high level if P1.0 is a low level, out of order communication unit and communication network are broken away from, carry out communication normally to ensure all the other communication units.
Resistance R 39 (12O Europe) is the pull-up resistor of B line, if the distributed capacitance of B line and COM line is 0.01 microfarad, and timeconstant=120 * 0.01=1.2 μ s, if baud rate is selected 3OKHz for use, wave form distortion can not surpass 10%.After increasing this pull-up resistor, increase the antijamming capability of communication line, improved the communication reliability.
The light-coupled isolation multilevel serial communication circuit of the utility model communication module adopts the VMOS pipe to drive (V1), drive the VMOS pipe and only need voltage signal, and the current driving ability of VMOS pipe is very strong, 256 same communication modules that a light-coupled isolation multilevel serial communication module can be driven be connected on the B line and communication unit thereof.
Claims (6)
1, a kind of light-coupled isolation multilevel serial communication module, the serial data that is connected in communication line and each communication unit sends, between receiving end, communication line comprises a power lead, a ground wire and a signal transmssion line, it is characterized in that: described module sends isolated variable circuit, an electronic switch, serial signal reception isolated variable circuit and a line current testing circuit by a serial signal and connects and composes; Described serial signal sends the serial data transmitting terminal that the isolated variable circuit connects described communication unit, serial signal sends the output of isolated variable circuit and connects electronic switch signal input end and line current testing circuit input end, the signal output part of electronic switch connects described signal transmssion line and serial signal receives the isolated variable circuit input end, serial signal receives the serial data receiving end that the isolated variable circuit output end connects described communication unit, the switch control end of electronic switch is connected a control signal output ends of news unit, and line current testing circuit output terminal is connected a signal input end of news unit.
2, light-coupled isolation multilevel serial communication module according to claim 1 is characterized in that: described serial signal transmission isolated variable circuit is linked in sequence by transistor input switching circuit, photoelectric isolating circuit and VMOS single tube voltage controlled current circuit and constitutes.
3, light-coupled isolation multilevel serial communication module according to claim 1 is characterized in that: described serial signal receives the isolated variable circuit and is made of photoelectric isolating circuit connection voltage contrasting amplified circuit.
4, light-coupled isolation multilevel serial communication module according to claim 1 is characterized in that: described line current testing circuit is linked in sequence by current sampling circuit, voltage comparator, photoelectric isolating circuit and amplifying circuit and constitutes.
5, light-coupled isolation multilevel serial communication module according to claim 1 is characterized in that: described electronic switch is a relay circuit by transistor driving.
6, light-coupled isolation multilevel serial communication module according to claim 1, it is characterized in that: the power lead of described each module and signal transmssion line span are connected to pull-up resistor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 96249258 CN2271729Y (en) | 1996-12-25 | 1996-12-25 | Optically coupled isolating multisequencing serial communication module |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 96249258 CN2271729Y (en) | 1996-12-25 | 1996-12-25 | Optically coupled isolating multisequencing serial communication module |
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| Publication Number | Publication Date |
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| CN2271729Y true CN2271729Y (en) | 1997-12-31 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 96249258 Expired - Fee Related CN2271729Y (en) | 1996-12-25 | 1996-12-25 | Optically coupled isolating multisequencing serial communication module |
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| CN (1) | CN2271729Y (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100535881C (en) * | 2007-04-29 | 2009-09-02 | 北京交通大学 | Asynchronous serial communication method based on electric current loop |
| CN102707138A (en) * | 2012-05-23 | 2012-10-03 | 福建顺昌虹润精密仪器有限公司 | Panel-mounted three-phase integrated coulombmeter based on DSC (dynamic stability control) technology |
| CN106533875A (en) * | 2016-12-13 | 2017-03-22 | 国网山东省电力公司 | RS485 line selector circuit |
| CN107998672A (en) * | 2017-12-29 | 2018-05-08 | 深圳市康柏特科技开发有限公司 | A kind of electronic building blocks electric connection system and method |
-
1996
- 1996-12-25 CN CN 96249258 patent/CN2271729Y/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100535881C (en) * | 2007-04-29 | 2009-09-02 | 北京交通大学 | Asynchronous serial communication method based on electric current loop |
| CN102707138A (en) * | 2012-05-23 | 2012-10-03 | 福建顺昌虹润精密仪器有限公司 | Panel-mounted three-phase integrated coulombmeter based on DSC (dynamic stability control) technology |
| CN102707138B (en) * | 2012-05-23 | 2015-01-21 | 福建顺昌虹润精密仪器有限公司 | Panel-mounted three-phase integrated coulombmeter based on DSC (dynamic stability control) technology |
| CN106533875A (en) * | 2016-12-13 | 2017-03-22 | 国网山东省电力公司 | RS485 line selector circuit |
| CN107998672A (en) * | 2017-12-29 | 2018-05-08 | 深圳市康柏特科技开发有限公司 | A kind of electronic building blocks electric connection system and method |
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| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C19 | Lapse of patent right due to non-payment of the annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |