CN209231761U - A kind of RS485 telecommunication circuit - Google Patents
A kind of RS485 telecommunication circuit Download PDFInfo
- Publication number
- CN209231761U CN209231761U CN201920156063.4U CN201920156063U CN209231761U CN 209231761 U CN209231761 U CN 209231761U CN 201920156063 U CN201920156063 U CN 201920156063U CN 209231761 U CN209231761 U CN 209231761U
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- resistance
- pin
- electrically connected
- conversion chip
- optocoupler
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Abstract
The utility model discloses be electrically connected with first unit, second unit and third unit in a kind of RS485 telecommunication circuit, including conversion chip U1, Yu Suoshu conversion chip U1；Compared with conventional three-wire system RS485 telecommunication circuit, the application simplifies control circuit, eliminates noise jamming, greatly improves communication speed under the premise of unobvious raising cost.
Description
Technical field
The utility model relates to fields of communication technology, and in particular to a kind of RS485 telecommunication circuit.
Background technique
RS485 telecommunication circuit is as a kind of communication pattern transmitted using differential signal, since its splendid resisting is done
Characteristic is disturbed, has great application in electronic communication field especially long haul communication field.In practical applications, due to monolithic
The TTL digital level of machine and the differential signal of RS485 are inconsistent, so needing once to be converted.
At present there are two types of conventional conversion circuits, respectively 3 line telecommunication circuits and 2 line telecommunication circuits.Wherein 3 line system
For telecommunication circuit there are hardware circuit and software design are complex, stability is poor；And there is reception signal in 2 line telecommunication circuits
In the presence of the burr interference of about 10uS, be not suitable for high-speed communication.The application is exactly to be directed to changing for conventional 2 line telecommunication circuits progress
Into thoroughly solving burr phenomena, can greatly improve communication speed.
Utility model content
The purpose of this utility model is to provide a kind of RS485 telecommunication circuits, deposit to solve existing 2 line telecommunication circuit
The problem of receiving signal jagged interference.
To achieve the above object, the technical solution of the utility model are as follows:
Be electrically connected in a kind of RS485 telecommunication circuit, including conversion chip U1, Yu Suoshu conversion chip U1 first unit,
Second unit and third unit.
Preferably, the first unit includes resistance R1, resistance R2 and optocoupler D1；One end of the resistance R1 is electrically connected to
The pin 4 and another termination power of the optocoupler D1；One end of the resistance R2 is electrically connected to the pin 1 of the optocoupler D1 and another
One termination power；The pin 3 of the optocoupler D1 is grounded；The pin 2 of the optocoupler D1 is electrically connected to the pin 1 of conversion chip U1.
Preferably, the second unit includes optocoupler D3, resistance R5, resistance R6, resistance R7, resistance R8 and triode Q1；
One end of the resistance R6 is electrically connected to the pin 1 of the optocoupler D3 and another termination power；The pin 3 of the optocoupler D3 connects
Ground；The pin 4 of the optocoupler D3, resistance R7, resistance R5 common end be electrically connected to the pin 4 of the conversion chip U1；It is described
Another termination power of resistance R5；The pin 1 of the triode Q1 is electrically connected to the other end of the resistance R7；The triode
The pin 2 of Q1 connects power supply；The common end of the pin 3 of the triode Q1 and the resistance R8 are electrically connected to the conversion chip U1
Pin 2 and pin 3；The other end of the resistance R8 is grounded.
Preferably, the third unit includes resistance R3, resistance R4, capacitor C1, diac D2, fuse
FUSE1 and fuse FUSE2；The resistance R3, fuse FUSE1, diac D2 common end be electrically connected to institute
State the pin 6 of conversion chip U1；The resistance R4, fuse FUSE2, diac D2 common end be electrically connected to institute
State the pin 7 of conversion chip U1；The capacitor C1, the pin 8 of conversion chip U1, resistance R3 public termination power, capacitor C1
The other end ground connection；The pin 5 of the conversion chip U1 and the common end grounding of resistance R4.
The utility model has the advantages that
(1) compared with conventional three-wire system RS485 telecommunication circuit, the application simplifies control circuit, has saved 1 single-chip microcontroller
Control I/O port；Compared with conventional two-wire system RS485 telecommunication circuit, the application eliminates noise jamming, in unobvious raising cost
Under the premise of greatly improve communication speed.
Detailed description of the invention
Fig. 1 is the circuit diagram of the RS485 telecommunication circuit of utility model.
Fig. 2 is the circuit diagram of first unit in utility model.
Fig. 3 is the circuit diagram of second unit in utility model.
Fig. 4 is the schematic diagram of conversion chip U1 in utility model.
Fig. 5 is the schematic diagram of third unit in utility model.
Fig. 6 is before improving with jagged signal waveforms.
Fig. 7 is improved signal waveforms.
Specific embodiment
The following examples illustrate the utility model, but is not intended to limit the scope of the present invention.
Embodiment 1
Conventional 3 line RS485 telecommunication circuits be signal transmission direction foot is independent, using individual single-chip microcontroller IO into
Row control, design of hardware and software is more complex, without advantage in cost control and reliability.
Why conventional 2 line RS485 telecommunication circuits can abandon direction foot, because conversion chip is defaulted as receiving by it
State, when needing to send single-chip microcontroller TTL signal: when transmission " 0 ", chip transmission direction is switched to transmission state " 1 ", this
When send data pins ground connection, that is, realize send " 0 "；When transmission " 1 ", chip transmission direction is switched to default reception state
" 0 ", the top pull down resistor of RS485 bus maintains one state to supply rear terminal RS 485 terminal recognition at this time.Therefore it may be implemented just
Really communication.
Just because of RS485 conversion chip, there are transmission directions to switch to reception from transmission in sending data procedures, and
Data transmitting pin is grounded always, while bus data is switched to " 0 " there are the delay of a bit of time from " 1 ", eventually leads to
There is an of short duration level "0", i.e., the burr of one about 10uS in RS485 conversion chip.The burr is caused by circuit theory
Birth defect can not be filtered elimination by back-end circuit.
The technical solution of the present embodiment is to change the transmission data pins of conventional 2 lines by the level "0" being directly grounded
To take electricity from direction controlling pin, at this time when transmission direction is switched to default reception state from transmission, due to sending data pipe
Foot has been switched to " 1 " via " 0 " before this, and RS485 conversion chip will export stable high level " 1 " always at this time, will not
There are the burr phenomenas of 10uS.
The utility model RS485 telecommunication circuit is by conversion chip U1, optocoupler D1, optocoupler D3 i.e. other attached resistance capacitance groups
At wherein the pin 1 of U1 is that RS485 bus receives signal, and pin 2 is that receiving direction controls signal, low effective；Pin 3 is
Sending direction controls signal, Gao Youxiao；Pin 4 is to send data bit, pin 6, the AB line that pin 7 is RS485 bus.Work as place
When reception state, if 6 foot voltages are lower than 7 foot voltages, 1 foot exports low level " 0 ", otherwise exports high level " 1 "；When being in
When transmission state, if 4 level of pin is " 0 ", 6 foot voltages are lower than 7 foot voltages, and otherwise 6 foot voltages will be above 7 foot voltages.Light
The TTL that coupling D1 transmits single-chip microcontroller receives signal, and the TTL that D3 transmits single-chip microcontroller sends signal.
Usually 2,3 pins of U1 are defaulted as low level, i.e. reception state, and 1 foot level will react total threadiness of RS485 at this time
State, i.e., when 6 foot voltages are higher than 7 foot voltage, it is otherwise " 0 " that 1 foot level, which is " 1 ",.
When needing to send signal " 0 ", due to the conducting of optocoupler D3, the pin level that resistance R5 is connected with resistance R7 will
It can become low level " 0 ", triode Q2 is connected at this time, and the upper side level of resistance R8 becomes high level " 1 ", and U1, which is in, at this time sends
" 0 " state, it is low that the AB bus of rear end will become A high B, i.e. 6 foot voltages are higher than 7 feet, when needing to send signal " 1 ", by
It is no longer turned in optocoupler D3, the pin level that resistance R5 is connected with resistance R7 will become the high level " 1 " of default, resistance R8's
Upper side level becomes defaulting low level " 0 ", and U1 is in reception state at this time, and the level state of 4 feet is by no longer reaction in rear end
6, on 7 foot voltages, the data identification in RS485 bus will draw in capable maintenance by resistance R3, the upper and lower of resistance R4 at this time.
Embodiment 2
First is electrically connected in the RS485 telecommunication circuit of the present embodiment, including conversion chip U1, Yu Suoshu conversion chip U1
Unit, second unit and third unit.
The first unit includes resistance R1, resistance R2 and optocoupler D1；One end of the resistance R1 is electrically connected to the light
The pin 4 and another termination power of coupling D1；One end of the resistance R2 is electrically connected to the pin 1 of the optocoupler D1 and another termination
Power supply；The pin 3 of the optocoupler D1 is grounded；The pin 2 of the optocoupler D1 is electrically connected to the pin 1 of conversion chip U1.
The second unit includes optocoupler D3, resistance R5, resistance R6, resistance R7, resistance R8 and triode Q1；The resistance
One end of R6 is electrically connected to the pin 1 of the optocoupler D3 and another termination power；The pin 3 of the optocoupler D3 is grounded；The light
The pin 4 of coupling D3, resistance R7, resistance R5 common end be electrically connected to the pin 4 of the conversion chip U1；The resistance R5's is another
One termination power；
The pin 1 of the triode Q1 is electrically connected to the other end of the resistance R7；The pin 2 of the triode Q1 connects electricity
Source；The common end of the pin 3 of the triode Q1 and the resistance R8 are electrically connected to the pin 2 and pin of the conversion chip U1
3；The other end of the resistance R8 is grounded.
The third unit includes resistance R3, resistance R4, capacitor C1, diac D2, fuse FUSE1 and melts
Disconnected device FUSE2；The resistance R3, fuse FUSE1, diac D2 common end be electrically connected to the conversion chip
The pin 6 of U1；The resistance R4, fuse FUSE2, diac D2 common end be electrically connected to the conversion chip
The pin 7 of U1；
The capacitor C1, the pin 8 of conversion chip U1, resistance R3 public termination power, capacitor C1 the other end ground connection；
The pin 5 of the conversion chip U1 and the common end grounding of resistance R4.
Although above having made detailed description to the utility model with generality explanation and specific embodiment,
On the basis of the utility model, it can be made some modifications or improvements, this is apparent to those skilled in the art
's.Therefore, these modifications or improvements on the basis of without departing from the spirit of the present invention, belong to the utility model and want
Seek the range of protection.
Claims (3)
1. a kind of RS485 telecommunication circuit, which is characterized in that including conversion chip U1, be electrically connected on Yu Suoshu conversion chip U1
First unit, second unit and third unit；
The first unit includes resistance R1, resistance R2 and optocoupler D1；
One end of the resistance R1 is electrically connected to the pin 4 of the optocoupler D1 and another termination power；
One end of the resistance R2 is electrically connected to the pin 1 of the optocoupler D1 and another termination power；
The pin 3 of the optocoupler D1 is grounded；The pin 2 of the optocoupler D1 is electrically connected to the pin 1 of conversion chip U1.
2. RS485 telecommunication circuit according to claim 1, which is characterized in that the second unit includes optocoupler D3, resistance
R5, resistance R6, resistance R7, resistance R8 and triode Q1；
One end of the resistance R6 is electrically connected to the pin 1 of the optocoupler D3 and another termination power；
The pin 3 of the optocoupler D3 is grounded；
The pin 4 of the optocoupler D3, resistance R7, resistance R5 common end be electrically connected to the pin 4 of the conversion chip U1；It is described
Another termination power of resistance R5；
The pin 1 of the triode Q1 is electrically connected to the other end of the resistance R7；
The pin 2 of the triode Q1 connects power supply；
The common end of the pin 3 of the triode Q1 and the resistance R8 are electrically connected to the pin 2 of the conversion chip U1 and draw
Foot 3；The other end of the resistance R8 is grounded.
3. RS485 telecommunication circuit according to claim 1, which is characterized in that the third unit includes resistance R3, resistance
R4, capacitor C1, diac D2, fuse FUSE1 and fuse FUSE2；
The resistance R3, fuse FUSE1, diac D2 common end be electrically connected to drawing for the conversion chip U1
Foot 6；
The resistance R4, fuse FUSE2, diac D2 common end be electrically connected to drawing for the conversion chip U1
Foot 7；
The capacitor C1, the pin 8 of conversion chip U1, resistance R3 public termination power, capacitor C1 the other end ground connection；
The pin 5 of the conversion chip U1 and the common end grounding of resistance R4.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920156063.4U CN209231761U (en) | 2019-01-29 | 2019-01-29 | A kind of RS485 telecommunication circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920156063.4U CN209231761U (en) | 2019-01-29 | 2019-01-29 | A kind of RS485 telecommunication circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN209231761U true CN209231761U (en) | 2019-08-09 |
Family
ID=67511018
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201920156063.4U Expired - Fee Related CN209231761U (en) | 2019-01-29 | 2019-01-29 | A kind of RS485 telecommunication circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN209231761U (en) |
-
2019
- 2019-01-29 CN CN201920156063.4U patent/CN209231761U/en not_active Expired - Fee Related
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| 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: 20190809 Termination date: 20210129 |