CN205384464U - Isolation and automatic send and receive control circuit of RS -485 serial ports - Google Patents
Isolation and automatic send and receive control circuit of RS -485 serial ports Download PDFInfo
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- CN205384464U CN205384464U CN201521086342.6U CN201521086342U CN205384464U CN 205384464 U CN205384464 U CN 205384464U CN 201521086342 U CN201521086342 U CN 201521086342U CN 205384464 U CN205384464 U CN 205384464U
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Abstract
The utility model discloses an isolation and automatic send and receive control circuit of RS -485 serial ports, including the RS -485 transceiver, opto -coupler and automatic send and receive control module are kept apart to the double - circuit, wherein automatic send and receive control module includes resistance R1, resistance R2, resistance R3, resistance R4, electric capacity C1, diode D1 and triode Q1, a resistance R4 termination power voltage, another termination triode Q1's the collecting electrode and the messenger that sends of RS -485 transceiver can the pins, triode Q1's projecting pole and resistance R3's one end common ground, another termination triode Q1's of resistance R3 base and resistance R2, another terminating diode D1 of resistance R2, resistance R1 and electric capacity C1's one end, electric capacity C1's one end ground connection, the data sending terminal of opto -coupler and diode D1's the other end are kept apart to another termination double - circuit of resistance R1. Resistance R1 and electric capacity C1's value be configured as the data that make the RS -485 transceiver make can the pin with send voltage that the messenger can the pin and descend by the height and just in time be greater than and send the required time of one bit for the time of low level voltage to distinguishable.
Description
Technical field
This utility model relates to industrial control field, particularly relates to a kind of RS-485 serial ports automatic transceiving and controls and isolation circuit.
Background technology
RS-485 standard uses extensively in the fields such as Industry Control, power communication, intelligence instrument.But, in the site environments such as Industry Control, situation is complicated, often has electrical noise interference transmission line；When multisystem interconnects, between the ground of different system, can there is potential difference, form ground loop, whole system can be disturbed, the calamitous damage of system time serious, can be caused；There is likely to be high voltage or the big electric currents such as the potential current surge of damage equipment or harm personnel.Therefore, the isolation of RS-485 interface is necessary.
RS-485 communication interface signal is differential level form, and semiduplex mode works.Synchronization is only capable of transmission or receives, it is necessary to control the direction sending and receiving, the complete interactive communication of ability, it is ensured that receive and dispatch normally.Existing RS-485 is generally adopted software program and controls commutation.And utilize software to control RS-485 commutation and first can take controller pin, need to increase by a road isolation circuit under isolated instances, add cost, secondly under the environment having operating system, increase the development difficulty of embedded software and the software compatibility being not easy to.
Therefore, those skilled in the art is devoted to isolation and the automatic transceiving control circuit of developing a kind of RS-485 serial ports, it may be achieved RS-485 serial ports automatic transceiving controls and the isolation of serial ports output circuit and CPU part circuit.
Utility model content
Because the drawbacks described above of prior art, technical problem to be solved in the utility model is to utilize software to control RS-485 commutation first to take controller pin, need to increase by a road isolation circuit under isolated instances, add cost, secondly under the environment having operating system, increase the development difficulty of embedded software and the software compatibility being not easy to.
nullFor achieving the above object，This utility model provides isolation and the automatic transceiving control circuit of a kind of RS-485 serial ports，Including RS-485 transceiver、Dual path isolation optocoupler and automatic transceiving control module，Wherein automatic transceiving control module includes resistance R1、Resistance R2、Resistance R3、Resistance R4、Electric capacity C1、Diode D1 and audion Q1，Resistance R4 mono-terminates supply voltage，The colelctor electrode of another termination audion Q1 and the transmission of RS-485 transceiver enable pin，One end common ground of the emitter stage of audion Q1 and resistance R3，The base stage of another termination audion Q1 of resistance R3 and resistance R2，Another terminating diode D1 positive pole of resistance R2、One end of resistance R1 and electric capacity C1，One end ground connection of electric capacity C1，The data sending terminal of another termination dual path isolation optocoupler of resistance R1 and diode D1 negative pole.
Further, resistance R4 is configured to pull-up resistor.
Further, resistance R3 is configured to pull down resistor.
Further, RS-485 transceiver is ISL81487EIBZ.
Further, dual path isolation optocoupler is HCPL-2530.
Further, audion Q1 is 9013.
Further, diode D1 is 1N4004.
Further, the capacitance of electric capacity C1 is 0.1 μ F.
Further, the resistance value of resistance R1 is 1K Ω, and the resistance value of resistance R2 is 1K Ω, and the resistance value of resistance R3 is 1K Ω, and the resistance value of resistance R4 is 10K Ω.
Further, the value of resistance R1 and electric capacity C1 is configured to make the data of RS-485 transceiver enable pin and send the voltage enabling pin and dropped to the time that can recognize that as low level voltage by height just greater than the time sent required for a byte.
Circuit described in the utility model effectively by RS-485 serial port circuit and internal circuit isolation, and can make this serial port circuit realize automatic transceiving.This utility model adopts a two-way opto-coupler chip by RS-485 serial port circuit and internal circuit isolation, the output lead and the audion that utilize RS-485 serial ports control to realize RS-485 serial ports automatic transceiving, save the port resource of controller, improve the compatibility of software simultaneously and reduce the development difficulty of embedded program under an operating system, improving transmission range and the capacity of resisting disturbance of RS-485 serial ports greatly.
Below with reference to accompanying drawing, the technique effect of design of the present utility model, concrete structure and generation is described further, to be fully understood from the purpose of this utility model, feature and effect.
Accompanying drawing explanation
Fig. 1 is the circuit theory diagrams of a preferred embodiment of the present utility model.
Detailed description of the invention
This utility model is the isolation of RS-485 serial ports and automatic transceiving control circuit, as it is shown in figure 1, wherein:
U1 is dual path isolation optocoupler, and concrete model is that controller partial circuit and RS-485 circuit are isolated by HCPL-2530, U1, and VCC is controller power source, and ISO1-5V is serial port circuit power supply, and two-way power supply two-way isolation DC-DC provides.
U2 is RS485 transceiver, and concrete model is ISL81487EIBZ, C2 is the filter capacitor of this chip power pin.R5 is the pull-up resistor that this chip receives pin, and R7 is the pull-up resistor of serial ports output lead A, and R6 is the pull down resistor of serial ports output lead B.D2, D3 are 12V stabilivolt, play the effect of protection output level.R8, R9 are RS-485 serial ports output matching resistance.
R1, R2, R3, R4, Q1, C1, D1 constitute the automatic transceiving circuit of RS-485 serial ports.The RX end of the URAT module of controller is connected directly to outfan RXD, the TX end of optocoupler and is connected directly to the input TXD of optocoupler.This signal signal after light-coupled isolation is ISO1_RXD and ISO1_TXD.
nullResistance is passed through at transmitting terminal ISO1_TXD，Triode Q1 and high voltage (ISO1-5V) complete to send the control of logic，UART interface is at one's leisure，ISO1_TXD is high level，ISO1_TXD will by resistance R1 in the case、R2、R3 controls the ground level of audion Q1，Q1 is made to turn on，Drag down RE and the DE port of U2 (RS485 transceiver)，So that U1 chip is in reception state，When microprocessor needs to send，It is low level by putting ISO1_TXD，So that triode Q1 is in cut-off state，Reach to set high the effect of RE and the DE port of U2，Realize the transmission of TXDA low level，A high position of ISO1_TXD is represented by the Idle state of U2，Finally realize the transmission flow of RS-485.
This circuit can also can adjust the parameter of resistance R1 and electric capacity C1 according to the difference of baud rate and the response speed being sent to reception pattern is adjusted the best, for 9600, one start bit, 8 bit data positions, one stops position, and sending a byte needs the time of ten bit data, the chances are 1ms, can pass through to adjust the value of resistance R1 and electric capacity C1, make the 2 of U2,3 foot voltages be dropped to the time that can recognize that as low level voltage by height just greater than 1ms.In actual (tube) length Distance Transmission, generally can select baud rate, and also because transmission line distance, the conversion speed requirements being sent to reception is relatively low, and this circuit is entirely capable of meeting the needs of actual (tube) length Distance Transmission.
Preferred embodiment of the present utility model described in detail above.Should be appreciated that the ordinary skill of this area just can make many modifications and variations according to design of the present utility model without creative work.Therefore, all technical staff in the art pass through the available technical scheme of logical analysis, reasoning, or a limited experiment on the basis of existing technology according to design of the present utility model, all should in the protection domain being defined in the patent claims.
Claims (10)
- null1. the isolation of a RS-485 serial ports and automatic transceiving control circuit，It is characterized in that，Including RS-485 transceiver、Dual path isolation optocoupler and automatic transceiving control module，Wherein automatic transceiving control module includes resistance R1、Resistance R2、Resistance R3、Resistance R4、Electric capacity C1、Diode D1 and audion Q1，Resistance R4 mono-terminates supply voltage，The colelctor electrode of another termination audion Q1 and the transmission of RS-485 transceiver enable pin，One end common ground of the emitter stage of audion Q1 and resistance R3，The base stage of another termination audion Q1 of resistance R3 and resistance R2，Another terminating diode D1 positive pole of resistance R2、One end of resistance R1 and electric capacity C1，One end ground connection of electric capacity C1，The data sending terminal of another termination dual path isolation optocoupler of resistance R1 and diode D1 negative pole.
- 2. the isolation of RS-485 serial ports as claimed in claim 1 and automatic transceiving control circuit, it is characterised in that described resistance R4 is configured to pull-up resistor.
- 3. the isolation of RS-485 serial ports as claimed in claim 1 and automatic transceiving control circuit, it is characterised in that described resistance R3 is configured to pull down resistor.
- 4. the isolation of RS-485 serial ports as claimed in claim 1 and automatic transceiving control circuit, it is characterised in that described RS-485 transceiver is ISL81487EIBZ.
- 5. the isolation of RS-485 serial ports as claimed in claim 1 and automatic transceiving control circuit, it is characterised in that described dual path isolation optocoupler is HCPL-2530.
- 6. the isolation of RS-485 serial ports as claimed in claim 1 and automatic transceiving control circuit, it is characterised in that described audion Q1 is 9013.
- 7. the isolation of RS-485 serial ports as claimed in claim 1 and automatic transceiving control circuit, it is characterised in that described diode D1 is 1N4004.
- 8. the isolation of RS-485 serial ports as claimed in claim 1 and automatic transceiving control circuit, it is characterised in that the capacitance of described electric capacity C1 is 0.1 μ F.
- 9. the isolation of RS-485 serial ports as claimed in claim 1 and automatic transceiving control circuit, it is characterised in that the resistance value of described resistance R1 is 1K Ω, and the resistance value of resistance R2 is 1K Ω, and the resistance value of resistance R3 is 1K Ω, and the resistance value of resistance R4 is 10K Ω.
- 10. the isolation of RS-485 serial ports as claimed in claim 1 and automatic transceiving control circuit, it is characterized in that, the value of described resistance R1 and electric capacity C1 is configured to make the data of RS-485 transceiver enable pin and send the voltage enabling pin and dropped to the time that can recognize that as low level voltage by height just greater than the time sent required for a byte.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201521086342.6U CN205384464U (en) | 2015-12-22 | 2015-12-22 | Isolation and automatic send and receive control circuit of RS -485 serial ports |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201521086342.6U CN205384464U (en) | 2015-12-22 | 2015-12-22 | Isolation and automatic send and receive control circuit of RS -485 serial ports |
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| CN205384464U true CN205384464U (en) | 2016-07-13 |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106253948A (en) * | 2016-08-31 | 2016-12-21 | 无锡蓝天电子股份有限公司 | A kind of repeater based on CPLD |
| CN107508613A (en) * | 2017-07-04 | 2017-12-22 | 广州致远电子有限公司 | Transmission circuit |
| CN109285258A (en) * | 2018-11-07 | 2019-01-29 | 郑州华力信息技术有限公司 | A kind of blue-teeth data retransmission unit with voice broadcast function |
-
2015
- 2015-12-22 CN CN201521086342.6U patent/CN205384464U/en active Active
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106253948A (en) * | 2016-08-31 | 2016-12-21 | 无锡蓝天电子股份有限公司 | A kind of repeater based on CPLD |
| CN106253948B (en) * | 2016-08-31 | 2019-09-20 | 无锡蓝天电子股份有限公司 | A kind of repeater based on CPLD |
| CN107508613A (en) * | 2017-07-04 | 2017-12-22 | 广州致远电子有限公司 | Transmission circuit |
| CN109285258A (en) * | 2018-11-07 | 2019-01-29 | 郑州华力信息技术有限公司 | A kind of blue-teeth data retransmission unit with voice broadcast function |
| CN109285258B (en) * | 2018-11-07 | 2024-05-24 | 郑州祥和集团有限公司 | Bluetooth data forwarding device with voice broadcasting function |
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