CN203301498U - Redundant communication circuit based on RS485 serial interface - Google Patents
Redundant communication circuit based on RS485 serial interface Download PDFInfo
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- CN203301498U CN203301498U CN2013201579188U CN201320157918U CN203301498U CN 203301498 U CN203301498 U CN 203301498U CN 2013201579188 U CN2013201579188 U CN 2013201579188U CN 201320157918 U CN201320157918 U CN 201320157918U CN 203301498 U CN203301498 U CN 203301498U
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Abstract
A redundant communication circuit based on RS485 serial interfaces comprises the design of RS485 serial interface circuits, isolation circuits and protective circuits. The RS485 serial interface circuits adopt two independent interface circuits which respectively perform communication with external equipment, and thus an aim of redundancy design is fulfilled. Optical coupling circuits are used for isolating the interface circuits and a microprocessor. The interface circuits are powered by separate isolated power sources, and thus the anti-interference capability of the circuits is improved. The protective circuits are composed of transient voltage suppressor diodes, resistors, capacitors and so on, and are used for preventing the interface circuits from being influenced by communication links. Through the redundancy design and anti-interference design of the RS485 serial interfaces, the reliability of RS485 serial communication is realized, and demands of industries such as the aerospace industry for highly reliable communication are satisfied.
Description
Technical field
The utility model belongs to the technology of serial communication field, relates to a kind of circuit of redundancy communication based on the RS485 serial line interface.
Background technology
In the application of some keys, reliability is primary, as the carrier rocket in aerospace system, satellite etc.In such environment, not only inclement condition, and system is disposable use, unrepairable, must higher requirement be proposed to the reliability of system.Redundancy is to improve one of reliability method preferably, is also the experience of a success.
The RS485 standard, as a kind of electrical code of differential data transmission, has the advantages such as noise suppressed is high, transmission rate is high, long transmission distance, is used in many different fields.Data-signal adopts the differential transfer mode,, also referred to as balance transmission, uses a pair of twisted-pair feeder, and wherein a line is defined as A, and another line is defined as B.In arbitrary moment, the RS-485 transceiver can only be operated in and receive or send one of two kinds of patterns.
The utility model content
The purpose of this utility model is: the reliability that improves existing technology of serial communication, a kind of circuit of redundancy communication based on the RS485 serial line interface is provided, this redundant interface technology adopts two interface circuits and optical coupling isolation circuit to carry out digital received and sent, two interface circuits are redundancy each other, improve the reliability of communication, guaranteed the normal operation of product.
Above-mentioned purpose of the present utility model is achieved by following technical solution:
A kind of circuit of redundancy communication based on the RS485 serial line interface, comprise three optical coupling isolation circuits, two RS485 interface circuits and protective circuit thereof, after the gating signal of external microprocessor is isolated by the second optical coupling isolation circuit, control two RS485 interface circuits and carry out the signal reception or send; The two-way external communication signal of redundancy each other is input in two RS485 interface circuits and carries out level match by two protective circuits respectively, and the same time has and Jin Youyi road external communication signal is input to the RS485 interface circuit by protective circuit, gating signal in being input to the RS485 interface circuit is under accepting state afterwards, external communication signal after level match is isolated by the first optical coupling isolation circuit, then export to external microprocessor;
After the transmitted signal of external microprocessor is isolated by the 3rd optical coupling isolation circuit, send into simultaneously in two RS485 interface circuits, the RS485 interface circuit carries out level match to the transmitted signal after isolation, exports by protective circuit more afterwards.
Described the first optical coupling isolation circuit comprises light-coupled isolation chip, resistance R 1 and capacitor C 1; External communication signal after described level match is input to the input negative terminal of light-coupled isolation chip, the output of light-coupled isolation chip is connected to external microprocessor, the output of the chip of light-coupled isolation simultaneously also connects power supply VCC by resistance R 1, the Enable Pin of light-coupled isolation chip and power end all are connected on power supply VCC, and Enable Pin and the power end of the chip of light-coupled isolation simultaneously also connect VCC ground by capacitor C 1.
Described the 3rd optical coupling isolation circuit structure is identical with the second optical coupling isolation circuit, and the second optical coupling isolation circuit comprises light-coupled isolation chip, resistance R 3, R6 and capacitor C 4; The gating signal of external microprocessor is input to the input negative terminal of light-coupled isolation chip, the input anode of light-coupled isolation chip is connected to power supply VCC by resistance R 6, the Enable Pin of light-coupled isolation chip and power end all are connected to power vd D, also by capacitor C 4, connect VDD ground simultaneously, the output of light-coupled isolation chip is connected to power vd D by resistance R 3.
Described two RS485 interface circuit structures are identical, and one of them comprises resistance R 4, capacitor C 2 and RS485 interface chip; Be connected by resistance R 4 between the input negative terminal of the first optical coupling isolation circuit and the reception output of RS485 interface chip, the reception Enable Pin of RS485 interface chip and driving Enable Pin are connected to the output of the second optical coupling isolation circuit, and the driving input of RS485 interface chip is connected to the output of the 3rd optical coupling isolation circuit; The power end of RS485 interface chip is connected to power vd D, also by capacitor C 2, connects VDD ground simultaneously.
the structure of described two protective circuits is identical, and one of them protective circuit comprises resistance R 8, R9, R12, R14, R16, capacitor C 8, C10, diode V1 and V3, outside port 1 negative signal is connected to the difference negative terminal of RS485 interface chip by resistance R 9, outside port 1 positive signal is connected to the difference anode of RS485 interface chip by resistance R 8, outside port 1 negative signal and positive signal respectively are connected VDD ground by diode V1 with V2, simultaneously, outside port 1 negative signal and positive signal also are connected VDD ground by capacitor C 8 respectively with C10, power vd D is connected to outside port 1 positive signal by resistance R 14, outside port 1 positive signal is connected to outside port 1 negative signal by resistance R 16 again, outside port 1 negative signal finally connects VDD ground by resistance R 12.
Described power supply VCC is identical with the VDD structure, includes capacitor C 6, C7, C12, C13, C14, C15, inductance L 1 and L2, choke L3, diode V5, V6 and power conversion chip; .
The 28V power end connects the anode of diode V5, and the negative electrode of diode V5 connects an end of inductance L 1, and the negative electrode of diode V5 also is connected to 28V power supply ground by diode V6 simultaneously, and the anode of diode V6 is connected with 28V power supply ground; The other end of inductance L 1 is connected with the input anode of choke L3, the input negative terminal of choke L3 directly and the 28V power supply link together, simultaneously, the other end of described inductance L 1 also is connected to 28V power supply ground by capacitor C 6 and the C12 that is connected in parallel, and the negative pole of capacitor C 12 connects 28V power supply ground;
The output plus terminal of choke L3 is connected to the input anode of power conversion chip, the output negative terminal of choke L3 connects the input negative terminal of power conversion chip, the output negative terminal of power conversion chip is connected on the shell of power conversion chip by capacitor C 13, the output negative terminal of power conversion chip is connected to by capacitor C 14 on the shell of power conversion chip, and the output negative terminal of power conversion chip is also connected to VDD power supply ground simultaneously; The output plus terminal of power conversion chip connects the VDD power supplys by inductance L 2, also by the capacitor C 7 that is connected in parallel, is connected connections with capacitor C between VDD power supply and VDD power supply ground, the negative pole connection VDD power supply ground of capacitor C 15.
The utility model compared with prior art has following beneficial effect:
(1) the utility model adopts the protective circuit that is comprised of transient voltage suppressor diode, resistance and electric capacity etc., has avoided the interference of communication link interface circuit.
(2) the utility model adopts optical coupling isolation circuit, has realized between interface circuit and micro-processor interface circuit
Electrical isolation, improved the antijamming capability of micro-processor interface circuit.
(3) the utility model interface circuit adopts Redundancy Design, and two circuit can carry out communication with external equipment respectively, have improved the reliability of communication.
Description of drawings
Fig. 1 is the utility model schematic block circuit diagram;
Fig. 2 is the circuit theory diagrams of the utility model based on the RS485 serial communication interface;
Fig. 3 is the utility model power principle figure.
Embodiment
Below in conjunction with accompanying drawing and specific embodiment, the utility model is described in further detail.
As shown in Figure 1, a kind of circuit of redundancy communication based on the RS485 serial line interface, comprise three optical coupling isolation circuits, two RS485 interface circuits and protective circuit thereof, after the gating signal of external microprocessor is isolated by the second optical coupling isolation circuit, control two RS485 interface circuits and carry out the signal reception or send; The two-way external communication signal of redundancy each other is input in two RS485 interface circuits and carries out level match by two protective circuits respectively, and the same time has and Jin Youyi road external communication signal is input to the RS485 interface circuit by protective circuit, gating signal in being input to the RS485 interface circuit is under accepting state afterwards, external communication signal after level match is isolated by the first optical coupling isolation circuit, then export to external microprocessor;
After the transmitted signal of external microprocessor is isolated by the 3rd optical coupling isolation circuit, send into simultaneously in two RS485 interface circuits, the RS485 interface circuit carries out level match to the transmitted signal after isolation, exports by protective circuit more afterwards.
As shown in Figure 2, the first optical coupling isolation circuit comprises light-coupled isolation chip, resistance R 1 and capacitor C 1; External communication signal after described level match is input to the input negative terminal of light-coupled isolation chip, the output of light-coupled isolation chip is connected to external microprocessor, the output of the chip of light-coupled isolation simultaneously also connects power supply VCC by resistance R 1, the Enable Pin of light-coupled isolation chip and power end all are connected on power supply VCC, and Enable Pin and the power end of the chip of light-coupled isolation simultaneously also connect VCC ground by capacitor C 1.
Described the 3rd optical coupling isolation circuit structure is identical with the second optical coupling isolation circuit, and the second optical coupling isolation circuit comprises light-coupled isolation chip, resistance R 3, R6 and capacitor C 4; The gating signal of external microprocessor is input to the input negative terminal of light-coupled isolation chip, the input anode of light-coupled isolation chip is connected to power supply VCC by resistance R 6, the Enable Pin of light-coupled isolation chip and power end all are connected to power vd D, also by capacitor C 4, connect VDD ground simultaneously, the output of light-coupled isolation chip is connected to power vd D by resistance R 3.
Described two RS485 interface circuit structures are identical, and one of them comprises resistance R 4, capacitor C 2 and RS485 interface chip; Be connected by resistance R 4 between the input negative terminal of the first optical coupling isolation circuit and the reception output of RS485 interface chip, the reception Enable Pin of RS485 interface chip and driving Enable Pin are connected to the output of the second optical coupling isolation circuit, and the driving input of RS485 interface chip is connected to the output of the 3rd optical coupling isolation circuit; The power end of RS485 interface chip is connected to power vd D, also by capacitor C 2, connects VDD ground simultaneously.
the structure of described two protective circuits is identical, and one of them protective circuit comprises resistance R 8, R9, R12, R14, R16, capacitor C 8, C10, diode V1 and V3, outside port 1 negative signal is connected to the difference negative terminal of RS485 interface chip by resistance R 9, outside port 1 positive signal is connected to the difference anode of RS485 interface chip by resistance R 8, outside port 1 negative signal and positive signal respectively are connected VDD ground by diode V1 with V2, simultaneously, outside port 1 negative signal and positive signal also are connected VDD ground by capacitor C 8 respectively with C10, power vd D is connected to outside port 1 positive signal by resistance R 14, outside port 1 positive signal is connected to outside port 1 negative signal by resistance R 16 again, outside port 1 negative signal finally connects VDD ground by resistance R 12.
Power supply VCC is identical with the VDD structure, as shown in Figure 3, includes capacitor C 6, C7, C12, C13, C14, C15, inductance L 1 and L2, choke L3, diode V5, V6 and power conversion chip; .
The 28V power end connects the anode of diode V5, and the negative electrode of diode V5 connects an end of inductance L 1, and the negative electrode of diode V5 also is connected to 28V power supply ground by diode V6 simultaneously, and the anode of diode V6 is connected with 28V power supply ground; The other end of inductance L 1 is connected with the input anode of choke L3, the input negative terminal of choke L3 directly and the 28V power supply link together, simultaneously, the other end of described inductance L 1 also is connected to 28V power supply ground by capacitor C 6 and the C12 that is connected in parallel, and the negative pole of capacitor C 12 connects 28V power supply ground;
The output plus terminal of choke L3 is connected to the input anode of power conversion chip, the output negative terminal of choke L3 connects the input negative terminal of power conversion chip, the output negative terminal of power conversion chip is connected on the shell of power conversion chip by capacitor C 13, the output negative terminal of power conversion chip is connected to by capacitor C 14 on the shell of power conversion chip, and the output negative terminal of power conversion chip is also connected to VDD power supply ground simultaneously; The output plus terminal of power conversion chip connects the VDD power supplys by inductance L 2, also by the capacitor C 7 that is connected in parallel, is connected connections with capacitor C between VDD power supply and VDD power supply ground, the negative pole connection VDD power supply ground of capacitor C 15.
The utility model is as follows based on the workflow of the redundancy communication method for designing of RS485 serial line interface:
The specific works flow process of redundancy communication: when data send, optocoupler B3 conducting work when transmitted signal is low level, the difference output end of two interface chips will send respectively the differential level signal.During data receiver, at first external equipment is connected to port one by test cable, carries out the reception of data.At this moment, outside port 1 will receive the differential level signal, and the reception output of interface chip D1 (1 pin) will be exported the high-low level pulse signal, optocoupler B2 conducting work during low level, thereby produce low level signal at the optocoupler output, make single-chip microcomputer receive data.As undesired in above-mentioned path communication, external equipment can be connected to port 2 by test cable, carries out the reception of data.At this moment, port 2 will receive the differential level signal, and the reception output of interface chip D2 (1 pin) will be exported the high-low level pulse signal, optocoupler B2 conducting work during low level, thus produce low level signal at the optocoupler output, make single-chip microcomputer receive data.
For protection RS485 serial ports network, guarantee system safety, increase interface protective circuit.In circuit diagram, adopt diode SMBJ V1～V4 protection RS485 interface chip SN55LBC176, avoid the chip high pressure that (thunderbolt, surge) produces when being subjected to external interference to damage the RS485 interface chip.In addition, the 390pF capacitor C 8～C11 in circuit is used for improving the EMI performance of circuit.When being connected to the 1K pull-up resistor R14 of port one positive signal, the 1K pull down resistor R12 that is connected to port one negative signal pin and being used for guaranteeing not interconnection network, circuit is in idle condition, to improve the functional reliability of equipment.Consider the special circumstances (short circuit as breakdown in the RS485 interface chip) of circuit, for preventing that in bus, the communication of miscellaneous equipment is affected, at connected resistance R 8～R11 of four 100 Ω of RS485 signal output part.
Optocoupler adopts HCPL5601, and transmission rate can reach 10MB/S, and circuit adopts independent insulating power supply power supply.The asynchronous communication data transmit in the mode of byte, before each byte transmits, first will realize shaking hands by a low level start bit.For preventing that interference signal false triggering receiver from producing negative saltus step, makes the receiving terminal microprocessor enter accepting state, external 10k Ω pull-up resistor R1.
The function of interface chip SN55LBC176 is to convert transmitted signal in communication network differential signal by transmitter, also the differential signal in communication network can be converted to the reception signal that is received by microprocessor by receiver.The reception signal of the standard serial mouth of microprocessor is by the reception output of optocoupler connecting interface chip, and transmitted signal is by the transmission drive end of optocoupler connecting interface chip.Enabled by the gating signal of the microprocessor output driver/receiver by the optocoupler control circuit: gating signal is 1, and the transmitter of circuit is effective, and receiver forbids, this moment, microprocessor can send data byte to the RS485 bus; Gating signal is 0, and the transmitter of circuit is forbidden, receiver is effective, and this moment, microprocessor can receive the data from the RS485 bus.
Power supply is input as 28V, by power transfer module MSA2805S, is transformed into 5V output, isolation mutually between power supply.Add transient voltage suppressor diode V6(SY5647A at the 28V input) and anti-reverse diode V5(2DK180), adopt inductance L 1(SD0402), 10u capacitor C 12 and 0.1u capacitor C 6 carry out differential mode filtering, 0.047uF capacitor C 13～C14 carries out common mode filtering; Output employing inductance L 2(SD0402), 10u capacitor C 15 and 0.1u capacitor C 7 are carried out differential mode filtering., through the common and different mode filter design of power supply input, output, effectively reduce the ripple of output voltage.
Be not described in detail the known technology that content belongs to this area professional and technical personnel in the utility model specification.
Claims (6)
1. circuit of the redundancy communication based on the RS485 serial line interface, it is characterized in that: comprise three optical coupling isolation circuits, two RS485 interface circuits and protective circuit thereof, after the gating signal of external microprocessor is isolated by the second optical coupling isolation circuit, control two RS485 interface circuits and carry out the signal reception or send; The two-way external communication signal of redundancy each other is input in two RS485 interface circuits and carries out level match by two protective circuits respectively, and the same time has and Jin Youyi road external communication signal is input to the RS485 interface circuit by protective circuit, gating signal in being input to the RS485 interface circuit is under accepting state afterwards, external communication signal after level match is isolated by the first optical coupling isolation circuit, then export to external microprocessor;
After the transmitted signal of external microprocessor is isolated by the 3rd optical coupling isolation circuit, send into simultaneously in two RS485 interface circuits, the RS485 interface circuit carries out level match to the transmitted signal after isolation, exports by protective circuit more afterwards.
2. a kind of circuit of redundancy communication based on the RS485 serial line interface according to claim 1, it is characterized in that: described the first optical coupling isolation circuit comprises light-coupled isolation chip, resistance R 1 and capacitor C 1; External communication signal after described level match is input to the input negative terminal of light-coupled isolation chip, the output of light-coupled isolation chip is connected to external microprocessor, the output of the chip of light-coupled isolation simultaneously also connects power supply VCC by resistance R 1, the Enable Pin of light-coupled isolation chip and power end all are connected on power supply VCC, and Enable Pin and the power end of the chip of light-coupled isolation simultaneously also connect VCC ground by capacitor C 1.
3. a kind of circuit of redundancy communication based on the RS485 serial line interface according to claim 1, it is characterized in that: described the 3rd optical coupling isolation circuit structure is identical with the second optical coupling isolation circuit, and the second optical coupling isolation circuit comprises light-coupled isolation chip, resistance R 3, R6 and capacitor C 4; The gating signal of external microprocessor is input to the input negative terminal of light-coupled isolation chip, the input anode of light-coupled isolation chip is connected to power supply VCC by resistance R 6, the Enable Pin of light-coupled isolation chip and power end all are connected to power vd D, also by capacitor C 4, connect VDD ground simultaneously, the output of light-coupled isolation chip is connected to power vd D by resistance R 3.
4. a kind of circuit of redundancy communication based on the RS485 serial line interface according to claim 1, it is characterized in that: described two RS485 interface circuit structures are identical, and one of them comprises resistance R 4, capacitor C 2 and RS485 interface chip; Be connected by resistance R 4 between the input negative terminal of the first optical coupling isolation circuit and the reception output of RS485 interface chip, the reception Enable Pin of RS485 interface chip and driving Enable Pin are connected to the output of the second optical coupling isolation circuit, and the driving input of RS485 interface chip is connected to the output of the 3rd optical coupling isolation circuit; The power end of RS485 interface chip is connected to power vd D, also by capacitor C 2, connects VDD ground simultaneously.
5. a kind of circuit of redundancy communication based on the RS485 serial line interface according to claim 1, it is characterized in that: the structure of described two protective circuits is identical, and one of them protective circuit comprises resistance R 8, R9, R12, R14, R16, capacitor C 8, C10, diode V1 and V3, outside port 1 negative signal is connected to the difference negative terminal of RS485 interface chip by resistance R 9, outside port 1 positive signal is connected to the difference anode of RS485 interface chip by resistance R 8, outside port 1 negative signal and positive signal respectively are connected VDD ground by diode V1 with V2, simultaneously, outside port 1 negative signal and positive signal also are connected VDD ground by capacitor C 8 respectively with C10, power vd D is connected to outside port 1 positive signal by resistance R 14, outside port 1 positive signal is connected to outside port 1 negative signal by resistance R 16 again, outside port 1 negative signal finally connects VDD ground by resistance R 12.
6. a kind of circuit of redundancy communication based on the RS485 serial line interface according to claim 3, it is characterized in that: described power supply VCC is identical with the VDD structure, include capacitor C 6, C7, C12, C13, C14, C15, inductance L 1 and L2, choke L3, diode V5, V6 and power conversion chip; .
The 28V power end connects the anode of diode V5, and the negative electrode of diode V5 connects an end of inductance L 1, and the negative electrode of diode V5 also is connected to 28V power supply ground by diode V6 simultaneously, and the anode of diode V6 is connected with 28V power supply ground; The other end of inductance L 1 is connected with the input anode of choke L3, the input negative terminal of choke L3 directly and the 28V power supply link together, simultaneously, the other end of described inductance L 1 also is connected to 28V power supply ground by capacitor C 6 and the C12 that is connected in parallel, and the negative pole of capacitor C 12 connects 28V power supply ground;
The output plus terminal of choke L3 is connected to the input anode of power conversion chip, the output negative terminal of choke L3 connects the input negative terminal of power conversion chip, the output negative terminal of power conversion chip is connected on the shell of power conversion chip by capacitor C 13, the output negative terminal of power conversion chip is connected to by capacitor C 14 on the shell of power conversion chip, and the output negative terminal of power conversion chip is also connected to VDD power supply ground simultaneously; The output plus terminal of power conversion chip connects the VDD power supplys by inductance L 2, also by the capacitor C 7 that is connected in parallel, is connected connections with capacitor C between VDD power supply and VDD power supply ground, the negative pole connection VDD power supply ground of capacitor C 15.
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| CN2013201579188U CN203301498U (en) | 2013-03-29 | 2013-03-29 | Redundant communication circuit based on RS485 serial interface |
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| CN2013201579188U CN203301498U (en) | 2013-03-29 | 2013-03-29 | Redundant communication circuit based on RS485 serial interface |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106300300A (en) * | 2016-10-11 | 2017-01-04 | 南京南瑞继保电气有限公司 | A kind of redundancy communication method for DC control and protection system |
| CN106788281A (en) * | 2016-12-28 | 2017-05-31 | 重庆金鑫科技产业发展有限公司 | A kind of RS485 signal amplifying apparatus |
| CN108599589A (en) * | 2018-06-20 | 2018-09-28 | 瑞纳智能设备股份有限公司 | A kind of isolated low power consumption power supply automatic switchover communication device |
-
2013
- 2013-03-29 CN CN2013201579188U patent/CN203301498U/en not_active Expired - Lifetime
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106300300A (en) * | 2016-10-11 | 2017-01-04 | 南京南瑞继保电气有限公司 | A kind of redundancy communication method for DC control and protection system |
| CN106788281A (en) * | 2016-12-28 | 2017-05-31 | 重庆金鑫科技产业发展有限公司 | A kind of RS485 signal amplifying apparatus |
| CN108599589A (en) * | 2018-06-20 | 2018-09-28 | 瑞纳智能设备股份有限公司 | A kind of isolated low power consumption power supply automatic switchover communication device |
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