CN209708119U - A kind of half-duplex RS 232-RS485 automatic switching circuit and communication equipment - Google Patents
A kind of half-duplex RS 232-RS485 automatic switching circuit and communication equipment Download PDFInfo
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- CN209708119U CN209708119U CN201920904077.XU CN201920904077U CN209708119U CN 209708119 U CN209708119 U CN 209708119U CN 201920904077 U CN201920904077 U CN 201920904077U CN 209708119 U CN209708119 U CN 209708119U
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Abstract
Present disclose provides a kind of half-duplex RS 232-RS485 automatic switching circuit and communication equipments, including RS232 level conversion module, RS485 level switch module and transmitting-receiving switching levels generation module, the RS232 level conversion module and RS485 level switch module communicate to connect, for RS232 level conversion at Transistor-Transistor Logic level and to be conveyed to RS485 level switch module, the RS485 level switch module is used to the Transistor-Transistor Logic level conversion module received being converted into RS485 differential level；The transmitting-receiving switching levels generation module and the output end of RS232 level conversion module connect, for generating transmitting-receiving control level according to the Transistor-Transistor Logic level signal received and being sent to RS485 level switch module, the transmitting-receiving for controlling RS485 level switch module is converted；Solve the problems, such as that different baud rates need the handoff delay time, conversion circuit automatic work under different baud rates does not need to be separately configured, cost is relatively low.
Description
Technical field
This disclosure relates to field of communication technology, in particular to a kind of half-duplex RS 232-RS485 automatic switching circuit and logical
Believe equipment.
Background technique
The statement of this part only there is provided background technique relevant to the disclosure, not necessarily constitutes the prior art.
Half-duplex RS 232-RS485 conversion circuit is largely used in industrial communication occasion at present, for turning RS232 interface
Change RS485 interface into, so that the data communication between host object and slave devices is completed, semiduplex RS485 telecommunication circuit
The needs according to sending and receiving data are needed, transmitting-receiving switching is carried out to half-duplex RS485 electrical level transferring chip.
The disclosed invention people has found under study for action, transmitting-receiving switching circuit that (1) generally uses at present be using single-chip microcontroller or
Complicated digital circuit completes transmission-receiving function switching, these conversion regime costs are relatively high；(2) above-mentioned conversion regime can all be met
To the delay time different problems that conversion needs when using different baud rates, thus cannot adaptive baud rate, every kind of baud
Rate requires a corresponding delay time, in use, delay time configuration error will influence whether communication quality, serious situation
Under, it will cause communication bus cisco unity malfunction.
Utility model content
In order to solve the deficiencies in the prior art, present disclose provides a kind of half-duplex RS 232-RS485 automatic switching circuits
And communication equipment, solve the problems, such as that different baud rates need the handoff delay time, conversion circuit is automatic under different baud rates
Work, does not need to be separately configured, does not need single-chip microcontroller or other complex digital circuitries, cost is relatively low yet.
To achieve the goals above, the disclosure adopts the following technical scheme that
In a first aspect, present disclose provides a kind of half-duplex RS 232-RS485 automatic switching circuits；
A kind of half-duplex RS 232-RS485 automatic switching circuit, including RS232 level conversion module, RS485 level conversion
Module and transmitting-receiving switching levels generation module, the RS232 level conversion module and RS485 level switch module communicate to connect,
For RS232 level conversion at Transistor-Transistor Logic level and to be conveyed to RS485 level switch module, the RS485 level switch module is used
RS485 differential level is converted into the Transistor-Transistor Logic level conversion module that will be received；The transmitting-receiving switching levels generation module with
The output end of RS232 level conversion module connects, concurrent for generating transmitting-receiving control level according to the Transistor-Transistor Logic level signal received
RS485 level switch module is given, the transmitting-receiving for controlling RS485 level switch module is converted.
As possible some implementations, the RS232 level conversion module includes a RS232 level conversion core
Piece, RS232 transmitting-receiving level passes through the first current-limiting resistance and the second current-limiting resistance respectively and the RS232 electrical level transferring chip connects
It connects, RS232 electrical level transferring chip is used for RS232 level conversion into Transistor-Transistor Logic level.
As possible some implementations, the RS485 level switch module includes a RS485 level conversion core
Piece, the RS485 electrical level transferring chip are used to for Transistor-Transistor Logic level to be converted into RS485 differential level, realize RS485 communication.
Limited as further, the RS485 electrical level transferring chip include RS485 level positive signal output end and
RS485 level negative signal output end, RS485 level positive signal output end export RS485 level after connecting with third current-limiting resistance
Positive signal, RS485 level negative signal output end export RS485 level negative signal after connecting with the 4th current-limiting resistance；RS485 level
Positive signal is connect by the first pull-up resistor with the first power supply, and RS485 level negative signal is by the first pull down resistor and ground line
Connection.
It is limited as further, the resistance value of first pull-up resistor and the first pull down resistor is identical.
Limited as further, the RS485 level positive signal output end and RS485 level negative signal output end it
Between be connected with terminal resistance, the terminal resistance is connected to after third current-limiting resistance and the 4th current-limiting resistance, terminal electricity
Remote networking of the resistance for RS485 communication.
Limited as further, further include RS485 level protective module, the RS485 level protective module with
The differential level output end of RS485 level switch module connects, for protecting the differential level signal of output not by surge impact.
It limits as further, two Transient Suppression Diode of the RS485 level protective module, respectively will
The positive and negative signal output end and ground line of RS485 level switch module connect, and two Transient Suppression Diodes distinguish third current limliting
After resistance and the 4th current-limiting resistance.
As possible some implementations, the transmitting-receiving switching levels generation module is by 555 chips and peripheral circuit
The monostable circuit of composition.
Second aspect, present disclose provides a kind of communication equipments, certainly including half-duplex RS 232-RS485 described in the disclosure
Dynamic conversion circuit.
Compared with prior art, the beneficial effect of the disclosure is:
The disclosure fully achieves the automatic conversion of RS232-RS485 level, and without communication baud rate when using
Gear selection, and have that circuit is simple, low in cost, the advantages of being hardly damaged.
Conversion circuit described in the disclosure is suitble to miniaturization, produces in enormous quantities, since elements all in the disclosure are all small
Type element, may be implemented whole Surface Mounting Technology productions, and manufacturing cost is extremely low.
Conversion circuit described in the disclosure is using 555 common chips, can be with according to the component parameters selected in the disclosure
Realize the half-duplex RS 232-RS485 communication of 110bps to 115200bps, the communication baud rate of 110bps to 115200bps is equal
Without changing circuit, whole automatic conversions, through measuring, RS485 level is complied fully in standard TIA/EIA-485-A to RS485
The regulation of level.
Detailed description of the invention
Fig. 1 is half-duplex RS 232-RS485 automatic switching circuit schematic diagram described in the embodiment of the present disclosure 1.
1-RS232 electrical level transferring chip；2-RS485 electrical level transferring chip；3- receives and dispatches switching levels generation module；4- first
Current-limiting resistance；The second current-limiting resistance of 5-；The second pull-up resistor of 6-；7- third pull-up resistor；8- first capacitor；The second capacitor of 9-；
The 5th current-limiting resistance of 10-；11-555 chip；12- third current-limiting resistance；The 4th current-limiting resistance of 13-；The first pull-up resistor of 14-；
The first pull down resistor of 15-；16- Transient Suppression Diode；17-RS485 level protective module；18- terminal resistance；19-RS485 electricity
Chip output circuit is changed in flat turn.
Specific embodiment
It is noted that following detailed description is all illustrative, it is intended to provide further instruction to the disclosure.Unless another
It indicates, all technical and scientific terms used herein has usual with disclosure person of an ordinary skill in the technical field
The identical meanings of understanding.
It should be noted that term used herein above is merely to describe specific embodiment, and be not intended to restricted root
According to the illustrative embodiments of the disclosure.As used herein, unless the context clearly indicates otherwise, otherwise singular
Also it is intended to include plural form, additionally, it should be understood that, when in the present specification using term "comprising" and/or " packet
Include " when, indicate existing characteristics, step, operation, device, component and/or their combination.
Embodiment 1:
As shown in Figure 1, the embodiment of the present disclosure 1 provides a kind of half-duplex RS 232-RS485 automatic switching circuit, including
RS232 level conversion module, RS485 level switch module and transmitting-receiving switching levels generation module 3, the RS232 level conversion
Module and RS485 level switch module communicate to connect, for RS232 level conversion at Transistor-Transistor Logic level and to be conveyed to RS485 level
Conversion module, the RS485 level switch module are used to the Transistor-Transistor Logic level conversion module received being converted into RS485 differential electrical
It is flat；The transmitting-receiving switching levels generation module and the output end of RS232 level conversion module connect, and receive for basis
Transistor-Transistor Logic level signal generates transmitting-receiving control level and is sent to RS485 level switch module, for controlling RS485 level conversion mould
The transmitting-receiving of block is converted.
The RS232 level conversion module includes a RS232 electrical level transferring chip 1, selects SP3232EEN chip,
RS232 transmitting-receiving level passes through the first current-limiting resistance 4 respectively and the second current-limiting resistance 5 connects with the RS232 electrical level transferring chip 1
It connects, RS232 electrical level transferring chip 1 is used for RS232 level conversion into Transistor-Transistor Logic level, the first current-limiting resistance 4 and the second current-limiting resistance
5 resistance value is 100 ohm.
The RS485 level switch module includes a RS485 electrical level transferring chip 2, selects MAX485 chip, described
RS485 electrical level transferring chip 2 is used to for Transistor-Transistor Logic level to be converted into RS485 differential level, realizes RS485 communication.
The RS485 electrical level transferring chip 2 includes that RS485 level positive signal output end and RS485 level negative signal export
End, is exported differential level by RS485 electrical level transferring chip circuit of output terminal 19, RS485 level positive signal output end and the
RS485 level positive signal is exported after the series connection of three current-limiting resistances 12, RS485 level negative signal output end and the 4th current-limiting resistance 13 are gone here and there
RS485 level negative signal is exported after connection；RS485 level positive signal is connect by the first pull-up resistor 14 with the first power supply VCC,
RS485 level negative signal output end is connected by the first pull down resistor 15 with ground line, the third current-limiting resistance 12 and the 4th
The resistance value of current-limiting resistance 13 is 20 ohm.
The resistance value of first pull-up resistor and the first pull down resistor is identical, is 5.1K ohm.
It is connected with terminal resistance 18 between the RS485 level positive signal output end and RS485 level negative signal output end,
The terminal resistance 18 is connected to after third current-limiting resistance 12 and the 4th current-limiting resistance 13, and the terminal resistance is used for RS485
The remote networking of communication, the resistance value of the terminal resistance are 120 ohm.
It further include RS485 level protective module, the RS485 level protective module 17 and RS485 level switch module
The connection of differential level output end, for protecting the differential level signal of output not by surge impact, the RS485 level protects mould
Two Transient Suppression Diode of block respectively connects the positive and negative signal output end of RS485 level switch module and ground line, two
After a Transient Suppression Diode difference third current-limiting resistance 12 and the 4th current-limiting resistance 13.
The transmitting-receiving switching levels generation module is the monostable circuit being made of 555 chips 11 and peripheral circuit, described
555 chips use NE555 chip, and wherein third pull-up resistor 7 and first capacitor 8 form resistance-capacitance network resistance, third pull-up electricity
The resistance value of resistance selects 10k ohm, and the capacitance of first capacitor 8 selects 220nF, and the resistance value of the second pull-up resistor 6 selects the Europe 10k
Nurse, the capacitance of the second capacitor 9 choose 100nF, and the resistance value of the 5th current-limiting resistance 10 chooses 100 ohm.
Specific works method are as follows: when sending signal TX level no signal, TX level is high level, at this time 555 chips
Triggering end T is high level, and the time constant of monostable circuit is determined by third pull-up resistor 7 and first capacitor 8, works as first capacitor
8 when being charged to 2/3VCC, and output end exports low level, this level controls the work of RS485 chip 2 in reception state.Work as beginning
When sending data, transmission signal TX is low level, and the triggering end T of 555 chips is low level at this time, according to the work of 555 chips
Logic can export rapidly high level, so that the work of RS485 chip 2 is in the state of transmission.In entire data transmission procedure, TX
It may be data 1, i.e. high level.When such transmission level is maintained to monostable flipflop time constant, capacitor 8 is charged to 2/
3VCC, transmitting-receiving control level can convert low level the short time, so that 2 short-term operation of RS485 chip is in reception state, but at this time the
RS485 level can be maintained at 1 level of data by one pull-up resistor 14 and the first pull down resistor 15, this is exactly that TX signal currently needs
The data of transmission, therefore have no effect on data transmission.In conclusion transmitting-receiving level generation module is according to the level for sending signal TX
Difference, to automatically realize the generation of transmitting-receiving switching levels.
Embodiment 2:
The embodiment of the present disclosure 2 provides a kind of communication equipment, including half-duplex RS 232- described in the embodiment of the present disclosure 1
RS485 automatic switching circuit.
The foregoing is merely preferred embodiment of the present disclosure, are not limited to the disclosure, for the skill of this field
For art personnel, the disclosure can have various modifications and variations.It is all within the spirit and principle of the disclosure, it is made any to repair
Change, equivalent replacement, improvement etc., should be included within the protection scope of the disclosure.
Claims (10)
1. a kind of half-duplex RS 232-RS485 automatic switching circuit, which is characterized in that including RS232 level conversion module,
RS485 level switch module and transmitting-receiving switching levels generation module, the RS232 level conversion module and RS485 level conversion
Module communication connection, for RS232 level conversion at Transistor-Transistor Logic level and to be conveyed to RS485 level switch module, the RS485
Level switch module is used to the Transistor-Transistor Logic level conversion module received being converted into RS485 differential level；The transmitting-receiving switching levels
Generation module and the output end of RS232 level conversion module connect, for generating transmitting-receiving control according to the Transistor-Transistor Logic level signal received
Level processed is simultaneously sent to RS485 level switch module, and the transmitting-receiving for controlling RS485 level switch module is converted.
2. half-duplex RS 232-RS485 automatic switching circuit as described in claim 1, which is characterized in that the RS232 level
Conversion module includes a RS232 electrical level transferring chip, and RS232 transmitting-receiving level passes through the first current-limiting resistance and the second current limliting respectively
Resistance is connect with the RS232 electrical level transferring chip, and RS232 electrical level transferring chip is used for RS232 level conversion into TTL electricity
It is flat.
3. half-duplex RS 232-RS485 automatic switching circuit as described in claim 1, which is characterized in that the RS485 level
Conversion module includes a RS485 electrical level transferring chip, and the RS485 electrical level transferring chip is for Transistor-Transistor Logic level to be converted into
RS485 differential level realizes RS485 communication.
4. half-duplex RS 232-RS485 automatic switching circuit as claimed in claim 3, which is characterized in that the RS485 level
Conversion chip includes RS485 level positive signal output end and RS485 level negative signal output end, the output of RS485 level positive signal
End exports RS485 level positive signal, RS485 level negative signal output end and the 4th current-limiting resistance after connecting with third current-limiting resistance
RS485 level negative signal is exported after series connection；RS485 level positive signal is connect by the first pull-up resistor with the first power supply, RS485
Level negative signal is connected by the first pull down resistor and ground line.
5. half-duplex RS 232-RS485 automatic switching circuit as claimed in claim 4, which is characterized in that first pull-up
The resistance value of resistance and the first pull down resistor is identical.
6. half-duplex RS 232-RS485 automatic switching circuit as claimed in claim 4, which is characterized in that the RS485 level
It is connected with terminal resistance between positive signal output end and RS485 level negative signal output end, the terminal resistance is connected to third
After current-limiting resistance and the 4th current-limiting resistance, the terminal resistance is used for the remote networking of RS485 communication.
7. half-duplex RS 232-RS485 automatic switching circuit as claimed in claim 4, which is characterized in that further include RS485 electricity
Flat protective module, the RS485 level protective module connect with the differential level output end of RS485 level switch module, are used for
Protect the differential level signal of output not by surge impact.
8. half-duplex RS 232-RS485 automatic switching circuit as claimed in claim 7, which is characterized in that the RS485 level
Two Transient Suppression Diode of protective module, respectively by the positive and negative signal output end of RS485 level switch module and ground line
Connection, two Transient Suppression Diodes are distinguished after third current-limiting resistances and the 4th current-limiting resistance.
9. half-duplex RS 232-RS485 automatic switching circuit as described in claim 1, which is characterized in that the transmitting-receiving conversion
Level generation module is the monostable circuit being made of 555 chips and peripheral circuit.
10. a kind of communication equipment, which is characterized in that certainly including the described in any item half-duplex RS 232-RS485 of claim 1-9
Dynamic conversion circuit.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920904077.XU CN209708119U (en) | 2019-06-14 | 2019-06-14 | A kind of half-duplex RS 232-RS485 automatic switching circuit and communication equipment |
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| CN201920904077.XU CN209708119U (en) | 2019-06-14 | 2019-06-14 | A kind of half-duplex RS 232-RS485 automatic switching circuit and communication equipment |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111404504A (en) * | 2020-06-03 | 2020-07-10 | 广州天嵌计算机科技有限公司 | RS485 bus differential signal amplifier |
| CN113608473A (en) * | 2021-08-06 | 2021-11-05 | 深圳爱特天翔科技有限公司 | RS232 bus management device and control system |
| CN113688079A (en) * | 2021-08-12 | 2021-11-23 | 江苏嘉擎信息技术有限公司 | Multi-level switching circuit for realizing communication current control |
-
2019
- 2019-06-14 CN CN201920904077.XU patent/CN209708119U/en active Active
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111404504A (en) * | 2020-06-03 | 2020-07-10 | 广州天嵌计算机科技有限公司 | RS485 bus differential signal amplifier |
| CN113608473A (en) * | 2021-08-06 | 2021-11-05 | 深圳爱特天翔科技有限公司 | RS232 bus management device and control system |
| CN113688079A (en) * | 2021-08-12 | 2021-11-23 | 江苏嘉擎信息技术有限公司 | Multi-level switching circuit for realizing communication current control |
| CN113688079B (en) * | 2021-08-12 | 2024-05-14 | 江苏嘉擎信息技术有限公司 | Multi-level switching circuit for realizing communication flow control |
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Address after: 250101 building 6, Yingxiu Road, Ji'nan hi tech Development Zone, Shandong, China, 2600 Patentee after: Shandong Huatian Technology Group Co.,Ltd. Patentee after: SHANDONG HOTEAM ELECTRICAL Co.,Ltd. Address before: 250101 building 6, Yingxiu Road, Ji'nan hi tech Development Zone, Shandong, China, 2600 Patentee before: SHANDONG HOTEAM TECHNOLOGIES Co.,Ltd. Patentee before: SHANDONG HOTEAM ELECTRICAL Co.,Ltd. |
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