CN202663433U - Receiving module of RS-485 communication circuit - Google Patents
Receiving module of RS-485 communication circuit Download PDFInfo
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- CN202663433U CN202663433U CN 201220282400 CN201220282400U CN202663433U CN 202663433 U CN202663433 U CN 202663433U CN 201220282400 CN201220282400 CN 201220282400 CN 201220282400 U CN201220282400 U CN 201220282400U CN 202663433 U CN202663433 U CN 202663433U
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Abstract
The utility model discloses a receiving module of an RS-485 communication circuit, which comprises an RS-485 chip N1, a first current-limiting resistor R2, a first filter capacitor C2, an optical coupler E1, a second filter capacitor C3, a second current-limiting resistor R1, a magnetic bead L1, a third current-limiting resistor R3, a triode V1, a resistor R4 and a resistor R5, wherein a collector electrode of a photosensitive triode of the optical coupler E1 is connected with the power supply end of a processor, an emitter electrode of the photosensitive triode is connected with a base electrode of the triode V1 through the second current-limiting resistor R3, a collector electrode of the triode V1 is respectively connected with the other ends of the second current-limiting resistor R1 and the magnetic bead L1, an emitter electrode of the triode V1 is grounded, a base electrode of the triode V1 is connected with one end of the resistor R4, and the other end of the resistor R4 is grounded. According to the receiving module, after a current transfer ratio (CTR) of the optical coupler is reduced, the communication is free of being influenced.
Description
Technical field
The utility model relates to a kind of RS-485 communicating circuit, specifically is the receiver module of RS-485 communicating circuit.
Background technology
System terminal has a kind of receiver module of RS-485 communicating circuit at present, this receiver module output is connected with processor UART receiving terminal, outside RS-485 differential signal is converted into Transistor-Transistor Logic level through 485 chips, Transistor-Transistor Logic level arrives processor UART receiving terminal through light-coupled isolation, consist of a half-duplex receiving system, described receiver module comprises RS-485 chip N1, the first current-limiting resistance R2, the first filter capacitor C2, optocoupler E1, the second filter capacitor C3, the second current-limiting resistance R1, magnetic bead L1, described the first current-limiting resistance R2 and optocoupler E1 consist of the optocoupler transmitting portion, the second current-limiting resistance R1 and optocoupler E1 consist of the optocoupler receiving unit, the end of described the first current-limiting resistance R2, the end of the first filter capacitor C2 is connected with the power end of RS-485 chip N1 respectively, the other end of the first filter capacitor C2 is connected with the earth terminal of RS-485 chip N1, the other end of the first current-limiting resistance R2 is connected with the positive pole of the light-emitting diode of optocoupler E1, the negative pole of the Light-Emitting Diode of optocoupler E1 is connected with the output of RS-485 chip, the collector electrode of the phototriode of optocoupler E1 respectively with the end of the second current-limiting resistance R1, the end of the second filter capacitor C3, the end of magnetic bead L1 connects, the grounded emitter of the phototriode of optocoupler E1, the other end of the second current-limiting resistance R1 is connected with the power end of processor, the other end ground connection of the second filter capacitor C3, the other end of magnetic bead L1 is connected with the receiving terminal of processor.
Work as optocoupler in the above-mentioned RS-485 communicating circuit through overaging, when perhaps badly work in long-time outside, optocoupler current transfer ratio CTR can occur and diminish, Ic diminishes, it is large that optocoupler Vce becomes, and surpassed processor TTL low level maximum, the problem of Communications failure in the high bit rate situation can occur.
The utility model content
Technical problem to be solved in the utility model is the receiver module that provides optocoupler current transfer ratio CTR to diminish the impregnable RS-485 communicating circuit of rear communication.
For solving the problems of the technologies described above, the receiver module of the RS-485 communicating circuit that the utility model provides, outside RS-485 differential signal is converted into Transistor-Transistor Logic level through the RS-485 chip, Transistor-Transistor Logic level arrives processor UART receiving terminal through light-coupled isolation, the receiver module of this RS-485 communicating circuit comprises RS-485 chip N1, the first current-limiting resistance R2, the first filter capacitor C2, optocoupler E1, the second filter capacitor C3, the second current-limiting resistance R1, magnetic bead L1, optocoupler E1 comprises a Light-Emitting Diode and a phototriode, the end of the first current-limiting resistance R2, the end of the first filter capacitor C2 is connected with the power end of RS-485 chip N1 respectively, the other end of the first filter capacitor C2 is connected with the earth terminal of RS-485 chip N1, the other end of the first current-limiting resistance R2 is connected with the positive pole of the light-emitting diode of optocoupler E1, the negative pole of the Light-Emitting Diode of optocoupler E1 is connected with the output of RS-485 chip, the end of the second current-limiting resistance R1 is connected with the power end of processor, the end of magnetic bead L1 is connected with the receiving terminal of processor, it also comprises the 3rd current-limiting resistance R3, triode V1, resistance R 4, resistance R 5, the collector electrode of the phototriode of described optocoupler E1 is connected with the power end of processor, the emitter of phototriode respectively with the end of the second current-limiting resistance R3, one end of resistance R 5, the end of the second filter capacitor C3 connects, the other end of resistance R 5, the other end of the second filter capacitor C3 is ground connection respectively, the other end of the second current-limiting resistance R3 is connected with the base stage of triode V1, the collector electrode of triode V1 respectively with the second current-limiting resistance R1, the other end of magnetic bead L1 connects, the grounded emitter of triode V1, the end of the base stage contact resistance R4 of triode V1, the other end ground connection of resistance R 4, the base voltage of 4 couples of triode V1 of resistance R plays bias, and resistance R 5 plays voltage zero setting effect.
After adopting above structure, the utility model compared with prior art has advantages of following:
After adopting the receiver module of above RS-485 communicating circuit, can effectively solve because after the current transfer ratio CTR of optocoupler E1 diminishes, Vce becomes the problem that causes greatly Communications failure, when Vce becomes large, because the effect of the 3rd current-limiting resistance R3 can make triode V1 be in conducting state, Vce remains on about 0.3V, be enough to guarantee the low level identification of processor, increased the reliability of RS-485 communicating circuit.
As improvement, the two ends of described the 3rd current-limiting resistance R3 also are connected to speed-up capacitor C1, the response speed of circuit when speed-up capacitor C1 can guarantee the signal high-speed transfer.
Description of drawings
Fig. 1 is the circuit theory diagrams of the receiver module of the utility model RS-485 communicating circuit.
Embodiment
Below in conjunction with the drawings and specific embodiments the utility model is described in more detail.
By the circuit theory diagrams of the receiver module of the utility model RS-485 communicating circuit shown in Figure 1 as can be known, it comprises RS-485 chip N1, the first current-limiting resistance R2, the first filter capacitor C2, optocoupler E1, the second filter capacitor C3, the second current-limiting resistance R1, magnetic bead L1, optocoupler E1 comprises a Light-Emitting Diode and a phototriode, the end of the first current-limiting resistance R2, the end of the first filter capacitor C2 is connected with the power end of RS-485 chip N1 respectively, the other end of the first filter capacitor C2 is connected with the earth terminal of RS-485 chip N1, the other end of the first current-limiting resistance R2 is connected with the positive pole of the light-emitting diode of optocoupler E1, the negative pole of the Light-Emitting Diode of optocoupler E1 is connected with the output of RS-485 chip, the end of the second current-limiting resistance R1 is connected with the power end of processor, the end of magnetic bead L1 is connected with the receiving terminal of processor, it also comprises the 3rd current-limiting resistance R3, triode V1, resistance R 4, resistance R 5, the collector electrode of the phototriode of described optocoupler E1 is connected with the power end of processor, the emitter of phototriode respectively with the end of the second current-limiting resistance R3, one end of resistance R 5, the end of the second filter capacitor C3 connects, the other end of resistance R 5, the other end of the second filter capacitor C3 is ground connection respectively, the other end of the second current-limiting resistance R3 is connected with the base stage of triode V1, the collector electrode of triode V1 respectively with the second current-limiting resistance R1, the other end of magnetic bead L1 connects, the grounded emitter of triode V1, the end of the base stage contact resistance R4 of triode V1, the other end ground connection of resistance R 4, outside RS-485 differential signal is converted into Transistor-Transistor Logic level through the RS-485 chip, Transistor-Transistor Logic level arrives processor UART receiving terminal through light-coupled isolation, the base voltage of 4 couples of triode V1 of resistance R plays bias, and resistance R 5 plays voltage zero setting effect.
The two ends of described the 3rd current-limiting resistance R3 also are connected to speed-up capacitor C1.
Below only use better example with regard to the utility model and made explanation, but can not be interpreted as it is limitations on claims, structure of the present utility model can have other variations, is not limited to said structure.In a word, all various variations of doing in the protection range of independent claims of the present utility model are all in protection range of the present utility model.
Claims (2)
1. the receiver module of a RS-485 communicating circuit, it comprises RS-485 chip N1, the first current-limiting resistance R2, the first filter capacitor C2, optocoupler E1, the second filter capacitor C3, the second current-limiting resistance R1, magnetic bead L1, optocoupler E1 comprises a Light-Emitting Diode and a phototriode, the end of the first current-limiting resistance R2, the end of the first filter capacitor C2 is connected with the power end of RS-485 chip N1 respectively, the other end of the first filter capacitor C2 is connected with the earth terminal of RS-485 chip N1, the other end of the first current-limiting resistance R2 is connected with the positive pole of the light-emitting diode of optocoupler E1, the negative pole of the Light-Emitting Diode of optocoupler E1 is connected with the output of RS-485 chip, the end of the second current-limiting resistance R1 is connected with the power end of processor, the end of magnetic bead L1 is connected with the receiving terminal of processor, it is characterized in that: it also comprises the 3rd current-limiting resistance R3, triode V1, resistance R 4, resistance R 5, the collector electrode of the phototriode of described optocoupler E1 is connected with the power end of processor, the emitter of phototriode respectively with the end of the second current-limiting resistance R3, one end of resistance R 5, the end of the second filter capacitor C3 connects, the other end of resistance R 5, the other end of the second filter capacitor C3 is ground connection respectively, the other end of the second current-limiting resistance R3 is connected with the base stage of triode V1, the collector electrode of triode V1 respectively with the second current-limiting resistance R1, the other end of magnetic bead L1 connects, the grounded emitter of triode V1, the end of the base stage contact resistance R4 of triode V1, the other end ground connection of resistance R 4.
2. the receiver module of RS-485 communicating circuit according to claim 1, it is characterized in that: the two ends of described the 3rd current-limiting resistance R3 also are connected to speed-up capacitor C1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220282400 CN202663433U (en) | 2012-06-15 | 2012-06-15 | Receiving module of RS-485 communication circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220282400 CN202663433U (en) | 2012-06-15 | 2012-06-15 | Receiving module of RS-485 communication circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN202663433U true CN202663433U (en) | 2013-01-09 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 201220282400 Expired - Lifetime CN202663433U (en) | 2012-06-15 | 2012-06-15 | Receiving module of RS-485 communication circuit |
Country Status (1)
| Country | Link |
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| CN (1) | CN202663433U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103954374A (en) * | 2014-05-22 | 2014-07-30 | 天津职业技术师范大学 | Remote temperature measuring device based on DS18B20 temperature sensor |
| CN109557859A (en) * | 2018-12-13 | 2019-04-02 | 珠海派诺科技股份有限公司 | Simple general use circuit based on RS-485 communication |
-
2012
- 2012-06-15 CN CN 201220282400 patent/CN202663433U/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103954374A (en) * | 2014-05-22 | 2014-07-30 | 天津职业技术师范大学 | Remote temperature measuring device based on DS18B20 temperature sensor |
| CN109557859A (en) * | 2018-12-13 | 2019-04-02 | 珠海派诺科技股份有限公司 | Simple general use circuit based on RS-485 communication |
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Legal Events
| Date | Code | Title | Description |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C56 | Change in the name or address of the patentee | ||
| CP03 | Change of name, title or address |
Address after: 315191 Yinzhou Industrial Park, Zhejiang, Ningbo, Yinzhou District, Ningbo Patentee after: NINGBO SANXING MEDICAL ELECTRIC CO., LTD. Address before: 315191 Zhejiang city of Ningbo province Jiangshan town Yinzhou District Mingguang Road No. 1166 Patentee before: Ningbo Sanxing Electric Co., Ltd. |
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| CX01 | Expiry of patent term | ||
| CX01 | Expiry of patent term |
Granted publication date: 20130109 |