CN207529181U - A kind of RS485 telecommunication circuits - Google Patents
A kind of RS485 telecommunication circuits Download PDFInfo
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- CN207529181U CN207529181U CN201721697367.9U CN201721697367U CN207529181U CN 207529181 U CN207529181 U CN 207529181U CN 201721697367 U CN201721697367 U CN 201721697367U CN 207529181 U CN207529181 U CN 207529181U
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Abstract
The utility model discloses a kind of RS485 telecommunication circuits, including sample circuit, RS485 ports, signal processing circuit, DC power supply, DC/DC modules and RS485 communication drive circuits；RS485 ports include signal isolation circuit, signaling conversion circuit and interface anti-clutter circuit, sample circuit, signal isolation circuit, signaling conversion circuit, interface anti-clutter circuit, signal processing circuit, RS485 communication drive circuits are linked in sequence successively, DC power supply is connect respectively with DC/DC modules, signal processing circuit, and DC/DC modules are connect with RS485 ports；Signal isolation circuit includes ISO7321 chips, the first capacitance and the second capacitance；First pin of ISO7321 chips is connect respectively with one end of power supply, the first capacitance, and the other end of the second capacitance is connected to ground, and the 8th pin of ISO7321 chips is connect respectively with one end of the second capacitance, independent 5V power supplys, the other end ground connection of the second capacitance；The 4th pin, the 5th pin of ISO7321 chips are grounded.
Description
Technical field
The utility model is related to field of communication technology, particularly a kind of RS485 telecommunication circuits.
Background technology
As a kind of common industrial circle communication bus, RS485 communications are with its communication distance is long, communication is stablized, wiring
Simply it is used widely.But it as the communication bus of a master-slave mode, usually requires that in bus and owns in actual use
Node is using host node as starting, until using bus topology between most end node and being connected in a manner of " handing in hand ".
The existing equipment using RS485 bus communications, existing 485 telecommunication circuits of RS include microprocessor chip,
Photoelectric isolating circuit and RS485 transponder chips.The serial communication of TTL level and RTS controls on microprocessor chip are carried out the coffin upon burial
Foot after being isolated by photoelectric isolating circuit, is connected on the TTL level pins of RS485 transponder chips, is received by RS485
Hair device chip is converted to A, B differential bus signal, is connected in RS485 buses.
Common twisted-pair feeder may be used in low speed, short distance, glitch-free occasion, conversely, in high speed, long-line transmission
When, then it must use impedance matching（Generally 120 Ω）RS485 private cables（STP-120Ω（For RS485 ＆ CAN）
A pair of of 18AWG）, and armored type paired shield cable should be also used in the case where interfering rugged environment（ASTP-120Ω（For
RS485 & CAN）A pair of of 18AWG）.
When using RS485 interfaces, for specific transmission line, from RS485 interfaces to its data signal transmission of load
The baud rate of permitted maximum cable length and signal transmission is inversely proportional, this length data mainly by distorted signals and is made an uproar
The factors such as sound are influenced.Theoretically, traffic rate 100Kbps and it is following when, the longest transmission range of RS485 is up to 1200
Rice, but the distance the transmitted in practical applications also difference due to transmission characteristic of chip and cable.It can in transmission process
To be amplified using the method for increasing relaying to signal, it can at most add eight relayings, that is to say, that theoretically RS485 is most
Big transmission range can reach 10.8 kilometers.If needing long distance transmission really, optical fiber may be used as propagation medium, transmitting-receiving
Both ends respectively add a photoelectric converter, and the transmission range of multimode fibre is 5 to 10 kilometers, and use single mode optical fiber up to 50 kilometers
Propagation distance.
In general, in industrial automation, in transformer and distribution power station monitoring system, the distribution of terminal data collection block generally use
Formula acquisition mode, measured data such as voltage, electric current, power etc., is generally connected to background monitoring system by fieldbus.
Current live bus types are more, as RS485 buses, CAN buses, Profibus buses, DeviceNet buses,
Longworks buses etc..Wherein due to RS485 bus hardwares are at low cost, easy realization, good reliability the features such as, so its
It is widely used in the intelligent automation device in industrial automation monitoring field.
RS485 buses are half-duplex bus, industry spot use, general communication speed under 19.2kpbs,
Bus transfer Distance Theory value is 1200 meters, but by the electromagnetic environmental impact of industry spot and the capacity institute of bus node
Limit, can actually transmit hundreds of meters it is even lower.
It is disadvantageous in that existing for technology at present：Firstly, since device is applied to industrial occasions, exist around device big
The electromagnetic interference signal of amount includes the interference of some interference signals, in addition device internal circuit that are introduced from RS485 buses, makes
Obtaining the bus communication ability actual performance of RS485 reduces, as communication distance shortens, the quantity of connecting node is reduced in bus.Its
Secondary, main control chip needs to be attached to realize that RS485 is communicated there are three signal wire with communication interface chip, wherein receive/
Hair.Send direction controlling line (Control) that main control chip (CPU) is needed to be controlled according to the current direction of data flow into line program,
It is relatively loaded down with trivial details.
Invention content
Technical problem to be solved in the utility model is overcome the deficiencies in the prior art and provides a kind of RS485 communications electricity
Road, the antijamming capability of the utility model enhancing RS485 communications, practical and reliability are high.
The utility model uses following technical scheme to solve above-mentioned technical problem：
According to the utility model proposes a kind of RS485 telecommunication circuits, including sample circuit, RS485 ports, signal processing
Circuit, DC power supply, DC/DC modules and RS485 communication drive circuits；RS485 ports include signal isolation circuit, signal is converted
Circuit and interface anti-clutter circuit, sample circuit, signal isolation circuit, signaling conversion circuit, interface anti-clutter circuit, at signal
Reason circuit, RS485 communication drive circuits are linked in sequence successively, and DC power supply connects respectively with DC/DC modules, signal processing circuit
It connects, DC/DC modules are connect with RS485 ports；Signal isolation circuit includes ISO7321 chips, the first capacitance and the second capacitance；
First pin of ISO7321 chips is connect respectively with one end of power supply, the first capacitance, and the other end of the second capacitance is connected to ground,
8th pin of ISO7321 chips is connect respectively with one end of the second capacitance, independent 5V power supplys, another termination of the second capacitance
Ground；The 4th pin, the 5th pin of ISO7321 chips are grounded.
Scheme is advanced optimized as a kind of RS485 telecommunication circuits described in the utility model, signaling conversion circuit is
RS485 signaling conversion circuits.
Scheme, RS485 signaling conversion circuits are advanced optimized as a kind of RS485 telecommunication circuits described in the utility model
Including first to 3rd resistor and MAX13487 chips；Wherein, the second pin of MAX13487 chips and MAX13487 chips
Third pin connects, the 5th pin of MAX13487 chips with, one end of first resistor connect respectively, first resistor it is another
End is connect respectively with the 5th pin of MAX13487 chips, one end of second resistance, the other end and 3rd resistor of second resistance
One end, MAX13487 chips the 6th pin connect respectively, the other end of 3rd resistor and independent current source, MAX13487 chips
The 8th pin connect respectively.
Scheme, interface anti-clutter circuit packet are advanced optimized as a kind of RS485 telecommunication circuits described in the utility model
Include RS485 telecommunication equipment lightning protection circuits.
Scheme is advanced optimized as a kind of RS485 telecommunication circuits described in the utility model, signal processing circuit includes
Microcontroller.
The utility model compared with prior art, has following technique effect using above technical scheme：
（1）The utility model can enhance the antijamming capability and driving force of RS485 communications；
（2）The RS485 interface circuits of the utility model are compacter, practical, and anti-interference and reliability is high.
Description of the drawings
Fig. 1 is the schematic diagram of the utility model.
Specific embodiment
The technical solution of the utility model is described in further detail below in conjunction with the accompanying drawings：
As shown in Figure 1, a kind of RS485 telecommunication circuits, including sample circuit, RS485 ports, signal processing circuit, direct current
Power supply, DC/DC modules and RS485 communication drive circuits；RS485 ports include signal isolation circuit, signaling conversion circuit and connect
Mouthful anti-clutter circuit, sample circuit, signal isolation circuit, signaling conversion circuit, interface anti-clutter circuit, signal processing circuit,
RS485 communication drive circuits are linked in sequence successively, and DC power supply is connect respectively with DC/DC modules, signal processing circuit, DC/DC
Module is connect with RS485 ports；Signal isolation circuit includes ISO7321 chips, the first capacitance and the second capacitance；ISO7321 cores
First pin of piece is connect respectively with one end of power supply, the first capacitance, and the other end of the second capacitance is connected to ground, ISO7321 cores
8th pin of piece is connect respectively with one end of the second capacitance, independent 5V power supplys, the other end ground connection of the second capacitance；
The 4th pin, the 5th pin of ISO7321 chips are grounded.
DC/DC power modules, for the 5V power supplys of DC supply input to be converted to the 5V power supplys by isolation, directly
The 5V power supplys for flowing power input are used to power to signal processing circuit, and the 5V power supplys by isolation are individually supplied to RS485 ports
Electricity so that realize isolated from power between RS485 ports and signal processing circuit.
Sample circuit by the signal of acquisition through signal isolation circuit, signaling conversion circuit, interface anti-clutter circuit export to
Signal processing circuit；RS485 communication drive circuits are connect with signal processing circuit, carry out the reception, transmission and processing of signal.
Signaling conversion circuit is RS485 signaling conversion circuits.
RS485 signaling conversion circuits include first to 3rd resistor and MAX13487 chips；Wherein, MAX13487 chips
Second pin is connect with the third pin of MAX13487 chips, the 5th pin and ground of MAX13487 chips, the one of first resistor
End connects respectively, and the other end of first resistor is connect respectively with one end of the 5th pin of MAX13487 chips, second resistance, the
The other end of two resistance and one end of 3rd resistor, the 6th pin of MAX13487 chips connect respectively, 3rd resistor it is another
End is connect respectively with the 8th pin of independent current source, MAX13487 chips.
Interface anti-clutter circuit includes RS485 telecommunication equipment lightning protection circuits.
Signal processing circuit includes microcontroller.
The above content is combine specific preferred embodiment further detailed description of the utility model, it is impossible to
Assert that the specific implementation of the utility model is confined to these explanations.For the ordinary skill of the utility model technical field
For personnel, without departing from the concept of the premise utility, several simple deductions or replacement can also be made, should all be regarded
To belong to the scope of protection of the utility model.
Claims (5)
1. a kind of RS485 telecommunication circuits, which is characterized in that including sample circuit, RS485 ports, signal processing circuit, direct current
Source, DC/DC modules and RS485 communication drive circuits；RS485 ports include signal isolation circuit, signaling conversion circuit and interface
Anti-clutter circuit, sample circuit, signal isolation circuit, signaling conversion circuit, interface anti-clutter circuit, signal processing circuit,
RS485 communication drive circuits are linked in sequence successively, and DC power supply is connect respectively with DC/DC modules, signal processing circuit, DC/DC
Module is connect with RS485 ports；Signal isolation circuit includes ISO7321 chips, the first capacitance and the second capacitance；ISO7321 cores
First pin of piece is connect respectively with one end of power supply, the first capacitance, and the other end of the second capacitance is connected to ground, ISO7321 cores
8th pin of piece is connect respectively with one end of the second capacitance, independent 5V power supplys, the other end ground connection of the second capacitance；
The 4th pin, the 5th pin of ISO7321 chips are grounded.
2. a kind of RS485 telecommunication circuits according to claim 1, which is characterized in that signaling conversion circuit is RS485 signals
Conversion circuit.
3. a kind of RS485 telecommunication circuits according to claim 1, which is characterized in that RS485 signaling conversion circuits include the
One to 3rd resistor and MAX13487 chips；Wherein, the second pin of MAX13487 chips and the third of MAX13487 chips are drawn
Foot connects, and the 5th pin of MAX13487 chips is connect respectively with one end of ground, first resistor, the other end of first resistor and
5th pin of MAX13487 chips, one end of second resistance connect respectively, the other end of second resistance and the one of 3rd resistor
End, MAX13487 chips the 6th pin connect respectively, the other end of 3rd resistor and independent current source, MAX13487 chips the
Eight pins connect respectively.
4. a kind of RS485 telecommunication circuits according to claim 1, which is characterized in that interface anti-clutter circuit includes RS485
Telecommunication equipment lightning protection circuit.
5. a kind of RS485 telecommunication circuits according to claim 1, which is characterized in that signal processing circuit includes microcontroller.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201721697367.9U CN207529181U (en) | 2017-12-08 | 2017-12-08 | A kind of RS485 telecommunication circuits |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201721697367.9U CN207529181U (en) | 2017-12-08 | 2017-12-08 | A kind of RS485 telecommunication circuits |
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| CN207529181U true CN207529181U (en) | 2018-06-22 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107966936A (en) * | 2017-12-08 | 2018-04-27 | 江苏飞视文化发展有限公司 | A kind of RS485 telecommunication circuits |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107966936A (en) * | 2017-12-08 | 2018-04-27 | 江苏飞视文化发展有限公司 | A kind of RS485 telecommunication circuits |
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