CN203859738U - Baud-rate self-adaption RS-485 isolator - Google Patents
Baud-rate self-adaption RS-485 isolator Download PDFInfo
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- CN203859738U CN203859738U CN201420257681.5U CN201420257681U CN203859738U CN 203859738 U CN203859738 U CN 203859738U CN 201420257681 U CN201420257681 U CN 201420257681U CN 203859738 U CN203859738 U CN 203859738U
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Abstract
The utility model discloses a Baud-rate self-adaption RS-485 isolator, and the isolator consists of a communication end (1), a first RS-485 chip (2), a photoelectric coupler, a second RS-485 chip (5), and a communication end (6). The photoelectric coupler is formed by the parallel connection of a first photoelectric coupler (3) and a second photoelectric coupler (4). The RS-485 chips (4, 5) of the isolator receive and transmit enable control signals which are automatically generated by bus communication data, and there is no need of additional control circuit and time-delay circuit, thereby achieving the automatic switching control of a data flow direction. The isolator achieves the real-time transparent transmission of data, is not affected by the change of the Baud rate of a bus, solves the problems that a conventional RS-485 isolator is complex in circuit structure and a communication Baud rate cannot be automatically suitable for the change of the Baud rate of the bus, is simple in circuit structure, is high in reliability, achieves the Baud-rate self-adaption function and the function of automatic recognition of the data flow direction.
Description
Technical field
The utility model belongs to measure and control instrument technical field, is specifically related to a kind of 485 communication isolator circuit for X-fluorescence ore grade analyzer, is also suitable for various RS-485 communication applications occasions simultaneously.
Background technology
In industry spot application, RS-485 communication is widely used.The communication speed of RS-485 bus is generally (2400～115200) bps.Conventionally RS-485 isolator control transponder chip reiving/transmitting state is taking a frame data time width as unit, different baud rates, and data time width is also different.In the time that communication baud rate changes, a frame data time width also can change, and requires RS-485 isolator can automatically adjust the time width of transceiving data, otherwise can cause communicating interrupt.
At present, existing RS-485 repeater cannot be accomplished automatically to adjust data transmit-receive time width, and major defect is as follows:
(1), when apply at scene, baud rate can not be adjusted adaptation automatically.Once after bus baud rate changes, the isolator baud rate of all 485 nodes need to reset;
(2) existing RS-485 isolator circuit structure complexity, the real-time of communication is poor, and telecommunication has the phenomenon of data packet loss often.
Summary of the invention
The purpose of this utility model is according to above-mentioned the deficiencies in the prior art part, and the baud rate self-adapting RS-485 isolator that a kind of circuit structure is simple, reliability is high, communication baud rate can adapt to the variation of bus baud rate is automatically provided.
For realizing above-mentioned purpose of the present utility model, the utility model baud rate self-adapting RS-485 isolator is realized by the following technical solutions:
The utility model baud rate self-adapting RS-485 isolator, it is to be made up of communication terminal, a RS-485 chip, photoelectrical coupler, the 2nd RS-485 chip portfolio.Described photoelectrical coupler is made up of the first photoelectrical coupler, the second photoelectrical coupler parallel connection; Current-limiting resistance of RO pin string of a described RS-485 chip, and be connected with the CA pin of the first photoelectrical coupler; After the RE of a described RS-485 chip, DE pin short circuit, be connected with the EM pin of the second photoelectrical coupler; The RO pin of described the 2nd RS-485 chip connects a current-limiting resistance of string and is connected with the CA pin of the second photoelectrical coupler.The receiver output RO of a described RS-485 chip connects a pull-up resistor, and the receiver output RO of the 2nd described RS-485 chip connects a pull-up resistor; A described RS-485 chip, the driver input end DI pin ground connection of the 2nd RS-485 chip, receiver output RO enables through the transmitting-receiving of the RS-485 chip of photoelectrical coupler control opposite side.The first described photoelectrical coupler, the CA pin of the second photoelectrical coupler connect respectively an electric capacity over the ground.A described RS-485 chip and bus interface A, the B of the 2nd RS-485 chip end connect respectively pull-up resistor and pull down resistor.Current-limiting resistance of D1 pin string of a described RS-485 chip, and be connected with the EM pin of the second photoelectrical coupler; Current-limiting resistance of D1 pin string of the 2nd described RS-485 chip, and be connected with the EM pin of the first photoelectrical coupler.
Described the first photoelectrical coupler, the second photoelectrical coupler model are 6N137; A described RS-485 chip, the model of the 2nd RS-485 chip are 65HVD3082ED.
The utility model baud rate self-adapting RS-485 isolator has following good effect after adopting above technical scheme: RS-485 chip receives and transmission enables control signal by bus communication data generation automatically itself, does not need extra control circuit and delay circuit.Control the transmission of data real-time transparent, the impact that not changed by bus baud rate thereby realize data flow automatic switchover.
Brief description of the drawings
Fig. 1 is the utility model baud rate self-adapting RS-485 isolator schematic block circuit diagram.
Accompanying drawing 2 is the utility model baud rate self-adapting RS-485 isolator circuit theory diagrams.
Reference numeral is: 1-communication terminal; 2-the one RS-485 chip; 3-the first photoelectrical coupler; 4-the second photoelectrical coupler; 5-the 2nd RS-485 chip; 6-communication terminal.
Embodiment
For further describing the utility model, below in conjunction with accompanying drawing, the utility model baud rate self-adapting RS-485 isolator is described in further detail.
The utility model baud rate self-adapting RS-485 isolator schematic block circuit diagram as shown in Figure 1 is also found out in conjunction with Fig. 2, the utility model provides baud rate self-adapting RS-485 isolator, is to be linked in sequence and to be formed by communication terminal 1, a RS-485 chip 2, photoelectrical coupler, the 2nd RS-485 chip 5, communication terminal 6.
The utility model baud rate self-adapting RS-485 isolator circuit theory diagrams as shown in Figure 2 also find out in conjunction with Fig. 1, and the utility model baud rate self-adapting RS-485 isolator is to be constituted by communication terminal 1, a RS-485 chip 2, photoelectrical coupler, the 2nd RS-485 chip 5, communication terminal 6.Described photoelectrical coupler is made up of the first photoelectrical coupler 3, the second photoelectrical coupler 4 parallel connections; Current-limiting resistance R5 of RO pin string of a described RS-485 chip 2, and be connected with the CA pin of the first photoelectrical coupler 3; After the RE of a described RS-485 chip 2, DE pin short circuit, be connected with the EM pin of the second photoelectrical coupler 4; The RO pin of described the 2nd RS-485 chip 5 meets a current-limiting resistance R7 of string and is connected with the CA pin of the second photoelectrical coupler 4.The receiver output RO of the one RS-485 chip 2 meets a pull-up resistor R4, and the receiver output RO of the 2nd described RS-485 chip 5 meets a pull-up resistor R8; A described RS-485 chip 2, the driver input end DI pin ground connection of the 2nd RS-485 chip 5, receiver output RO enables through the transmitting-receiving of the RS-485 chip of photoelectrical coupler control opposite side.
The CA pin of the first photoelectrical coupler 3, the second photoelectrical coupler 4 meets respectively a capacitor C 1, C2 over the ground; Bus interface A, the B end of the one RS-485 chip 2 and the 2nd RS-485 chip 5 connects respectively and draws resistance R 1, R10 and pull down resistor R2, R9; Current-limiting resistance R3 of D1 pin string of the one RS-485 chip 2, and be connected with the EM pin of the second photoelectrical coupler 4; Current-limiting resistance R6 of D1 pin string of the 2nd described RS-485 chip 5, and be connected with the EM pin of the first photoelectrical coupler 3.The first photoelectrical coupler 3, the second photoelectrical coupler 4 models are 6N137; A described RS-485 chip 2, the model of the 2nd RS-485 chip 5 are 65HVD3082ED.
The operation principle of the utility model baud rate self-adapting RS-485 isolator is:
When bus level is A1 while being greater than B1 200mV, the RO end of a RS-485 chip 2 is high level, the first photoelectrical coupler 3 outputs cut-offs, and DE, the RE/ end of the 2nd RS-485 chip 5 is low level by resistance R 6 ground connection.Now the 2nd RS-485 chip 5 in accepting state, driver is output as high-impedance state.Owing to above drawing and the effect of pull down resistor, the bus level A2 making is greater than B2.
When bus level is A1 while being less than B1 200mV, the RO end of a RS-485 chip 2 is low level, and the first photoelectrical coupler 3 is exported conducting, and DE, the RE/ end of the 2nd RS-485 chip 5 is pulled to high level.Now the receiving terminal of the 2nd RS-485 chip 5 is in high-impedance state, and driver output effectively.Due to DI end ground connection, A is low in driver output, and B is high.So the level A2 in bus is less than B2.
After data transmission finishes, the effect of bus interface A, B end pull-up resistor and pull down resistor makes RS-485 chip automatically get back to accepting state, no matter which side of bus carry out data all can be from dynamic response.Because RS-485 chip receives and transmission enables control signal by automatically generation of bus communication data itself, do not need extra control circuit and delay circuit, data flow automatically switches, the transmission of data communication real-time transparent, the impact that not changed by bus baud rate.
Claims (2)
1. a baud rate self-adapting RS-485 isolator, it is to be constituted by communication terminal (1), a RS-485 chip (2), photoelectrical coupler, the 2nd RS-485 chip (5), communication terminal (6), it is characterized in that: described photoelectrical coupler is by the first photoelectrical coupler (3), the second photoelectrical coupler (4) formation in parallel; A current-limiting resistance of RO pin string (R5) of a described RS-485 chip (2), and be connected with the CA pin of the first photoelectrical coupler (3); After the RE of a described RS-485 chip (2), DE pin short circuit, be connected with the EM pin of the second photoelectrical coupler (4); The RO pin of described the 2nd RS-485 chip (5) connects a current-limiting resistance of string (R7) and is connected with the CA pin of the second photoelectrical coupler (4);
The receiver output RO of a described RS-485 chip (2) connects a pull-up resistor (R4), and the receiver output RO of the 2nd described RS-485 chip (5) connects a pull-up resistor (R8); A described RS-485 chip (2), the driver input end DI pin ground connection of the 2nd RS-485 chip (5);
Described the first photoelectrical coupler (3), the CA pin of the second photoelectrical coupler (4) connect respectively an electric capacity (C1, C2) over the ground;
A described RS-485 chip (2) and bus interface A, the B of the 2nd RS-485 chip (5) end connect respectively pull-up resistor (R1, R10) and pull down resistor (R2, R9);
A current-limiting resistance of D1 pin string (R3) of a described RS-485 chip (2), and be connected with the EM pin of the second photoelectrical coupler (4); A current-limiting resistance of D1 pin string (R6) of the 2nd described RS-485 chip (5), and be connected with the EM pin of the first photoelectrical coupler (3).
2. according to the baud rate self-adapting RS-485 isolator described in claim 1, it is characterized in that: described the first photoelectrical coupler (3), the second photoelectrical coupler (4) model are 6N137; A described RS-485 chip (2), the model of the 2nd RS-485 chip (5) are 65HVD3082ED.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420257681.5U CN203859738U (en) | 2014-05-20 | 2014-05-20 | Baud-rate self-adaption RS-485 isolator |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420257681.5U CN203859738U (en) | 2014-05-20 | 2014-05-20 | Baud-rate self-adaption RS-485 isolator |
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| CN203859738U true CN203859738U (en) | 2014-10-01 |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106201940A (en) * | 2016-08-27 | 2016-12-07 | 谢怡涛 | A kind of control circuit for improving RS485 bus data transfer reliability |
| CN106301450A (en) * | 2016-09-30 | 2017-01-04 | 浙江方大智控科技有限公司 | Repeat circuit and half duplex communication circuit for half duplex communication |
| CN108072779A (en) * | 2017-12-20 | 2018-05-25 | 福建利利普光电科技有限公司 | A kind of digital oscilloscope CAN bus baud rate automatic identifying method |
| CN112639639A (en) * | 2018-08-06 | 2021-04-09 | 西门子股份公司 | Adaptive repeater for industrial communications |
| CN113037321A (en) * | 2021-03-11 | 2021-06-25 | 华立科技股份有限公司 | Communication module |
-
2014
- 2014-05-20 CN CN201420257681.5U patent/CN203859738U/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106201940A (en) * | 2016-08-27 | 2016-12-07 | 谢怡涛 | A kind of control circuit for improving RS485 bus data transfer reliability |
| CN106301450A (en) * | 2016-09-30 | 2017-01-04 | 浙江方大智控科技有限公司 | Repeat circuit and half duplex communication circuit for half duplex communication |
| CN108072779A (en) * | 2017-12-20 | 2018-05-25 | 福建利利普光电科技有限公司 | A kind of digital oscilloscope CAN bus baud rate automatic identifying method |
| CN112639639A (en) * | 2018-08-06 | 2021-04-09 | 西门子股份公司 | Adaptive repeater for industrial communications |
| CN113037321A (en) * | 2021-03-11 | 2021-06-25 | 华立科技股份有限公司 | Communication module |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20141001 Termination date: 20200520 |