CN206515816U - A kind of self-compensating RS485 circuits of optocoupler transmission delay - Google Patents
A kind of self-compensating RS485 circuits of optocoupler transmission delay Download PDFInfo
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- CN206515816U CN206515816U CN201720162609.8U CN201720162609U CN206515816U CN 206515816 U CN206515816 U CN 206515816U CN 201720162609 U CN201720162609 U CN 201720162609U CN 206515816 U CN206515816 U CN 206515816U
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Abstract
The utility model is related to a kind of self-compensating RS485 circuits of optocoupler transmission delay, including RS485 chips (U1), 485 signal receiving units being connected with the reception output end (R) of RS485 chips (U1) and 485 signal transmitting units being connected with the transmission input (D) of RS485 chips.The utility model realizes the compensation to low speed optocoupler transmission delay, and then solves the problem of low speed optocoupler can not realize high-speed communication, and RS485 chips need not be controlled using high speed photo coupling, and is not required to select special inverted device, reduces circuit design cost.
Description
Art
The utility model is related to a kind of RS485 circuits, and in particular to a kind of self-compensating RS485 electricity of optocoupler transmission delay
Road.
Background technology
RS485 interfaces send the transmission technology with differential received, tool as a kind of serial communication bus interface using balance
There is the ability of stronger suppression common mode interference.It is preferably to improve the anti-of RS485 circuits to do in the industrial circles such as remote meter reading
Ability is disturbed, optocoupler is usually added in RS485 circuits to realize preferable electrical isolation.However, by low speed optocoupler itself institute
The output latency issue of presence, when controlling 485 chips to carry out high-speed communication using low speed optocoupler, RS485 circuits are sent to always
" 1 " signal duration on line relative can shorten, and " 0 " the signal duration being sent in bus can be relative
It is elongated, counterpart device None- identified is gone out some " 1 " signals therein, and then cause communication failure.
The content of the invention
In view of the above-mentioned problems, the utility model provides a kind of self-compensating RS485 circuits of optocoupler transmission delay.
To solve the above problems, the technical solution of the utility model is：A kind of self-compensating RS485 electricity of optocoupler transmission delay
Road, including RS485 chips, 485 signal receiving units that are connected with the reception output end of RS485 chips and with RS485 chips
Send 485 connected signal transmitting units of input；The transmission of RS485 chips, which enables control end and received, enables control end short circuit
It is connected by delay circuit with 485 signal transmitting units, described delay circuit is：The transmission of RS485 chips enables control end
Enabled with receiving after control end short circuit through capacity earth, electric capacity two ends parallel connection triode；The base stage of triode connects through first resistor
The transmission input of RS485 chips is simultaneously connected to power supply through second resistance, and the colelctor electrode of triode is connected to power supply, three through 3rd resistor
The grounded emitter of pole pipe.
Described 485 signal receiving units, 485 signal transmitting units are between connection RS485 chips and processor
Optical coupling isolator.
The utility model enables control end and RS485 circuits by enabling control end in the transmission of RS485 chips and receiving
Earth terminal between access a suitable storage capacitor, when 485 signal transmitting units transmission 0 signal when, it is necessary first to this
Storage capacitor is charged, and RS485 chips is just changed into transmission state from reception state after a predetermined time, is realized to low speed light
The compensation of coupling transmission delay, and then solve the problem of low speed optocoupler can not realize high-speed communication.Wherein, the utility model circuit is adopted
With the reverse process of the complete pair signals of triode, while providing good discharge loop for storage capacitor, it is ensured that storage capacitor is put
Quick response when electric, it is succinct convenient to be realized in circuit design.In circuit design, suitable energy storage electricity need to be only chosen
Hold, high-speed communication just can be realized using low speed optocoupler control RS485 chips, without controlling RS485 chips using high speed photo coupling,
And be not required to select special inverted device, reduce circuit design cost.
Brief description of the drawings
Fig. 1 is circuit theory diagrams of the present utility model.
Embodiment
As shown in figure 1, a kind of self-compensating RS485 circuits of optocoupler transmission delay, including RS485 chips U1 and RS485 cores
485 connected piece U1 reception output end R signal receiving units and 485 signals being connected with the transmission input D of RS485 chips
Transmitting element；Described 485 signal receiving units, 485 signal transmitting units are to be connected between RS485 chips and processor
Optical coupling isolator.
RS485 chips U1 transmission enables control end DE and received and enables after control end RE short circuits through delay circuit and 485
Signal transmitting unit is connected, and described delay circuit is：RS485 chips U1 transmission, which enables control end DE and received, enables control
Hold after RE short circuits through electric capacity C1 ground connection G485, electric capacity C1 two ends parallel connection triode Q1；Triode Q1 base stage is through first resistor R1
Meet the transmission input D of RS485 chips and be connected to power supply V485 through second resistance R2, triode Q1 colelctor electrode is through 3rd resistor
R3 is connected to power supply V485, triode Q1 grounded emitter G485.
And the A ends of RS485 chips are by connecting power supply after resistance R5, B ends by be grounded after resistance R6 and respectively with
RS485 interfaces 485A, 485B are connected.
1 signal that the utility model is sent is pulled by A, B port resistance to power supply and over the ground, and 0 signal is by this circuit
Itself driving.When sending data, the transmission input of RS485 chips is changed into after 0 signal from 1 signal, and RS485 cores are docked at first
The reception of piece, which enables control end and sends the storage capacitor enabled between control end and the earth terminal of this circuit, is charged, until
The voltage at storage capacitor two ends exceedes after certain value, and this circuit can just drive out 0 signal, realizes to low speed optocoupler transmission delay
Compensation, and then solve low speed optocoupler the problem of can not realize high-speed communication.As long as selecting a suitable RC circuit, it is determined that
Go out a suitable charging interval, compensate the transmission delay brought by optocoupler, make in bus " 1 " signal and the equal energy of " 0 " signal
There is a suitable duration, be that high-speed communication can be achieved using low speed optocoupler.
Claims (2)
1. a kind of self-compensating RS485 circuits of optocoupler transmission delay, including RS485 chips (U1), connect with RS485 chips (U1)
Receive 485 connected signal receiving units of output end (R) and 485 signals being connected with the transmission input (D) of RS485 chips are sent
Unit；It is characterized in that：The transmission of RS485 chips (U1) enables control end (DE) and passed through after receiving enable control end (RE) short circuit
Delay circuit is connected with 485 signal transmitting units, and described delay circuit is：The transmission of RS485 chips (U1) enables control end
(DE) (G485) and after receiving enable control end (RE) short circuit is grounded through electric capacity (C1), electric capacity (C1) two ends parallel connection triode
(Q1)；The base stage of triode (Q1) connects the transmission input (D) of RS485 chips and through second resistance (R2) through first resistor (R1)
Power supply (V485) is connected to, the colelctor electrode of triode (Q1) is connected to power supply (V485), the hair of triode (Q1) through 3rd resistor (R3)
Emitter grounding (G485).
2. the self-compensating RS485 circuits of optocoupler transmission delay according to claim 1, it is characterised in that：485 described letters
Number receiving unit, 485 signal transmitting units are the optical coupling isolator for being connected to RS485 chips (U1) between processor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201720162609.8U CN206515816U (en) | 2017-02-22 | 2017-02-22 | A kind of self-compensating RS485 circuits of optocoupler transmission delay |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201720162609.8U CN206515816U (en) | 2017-02-22 | 2017-02-22 | A kind of self-compensating RS485 circuits of optocoupler transmission delay |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN206515816U true CN206515816U (en) | 2017-09-22 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201720162609.8U Active CN206515816U (en) | 2017-02-22 | 2017-02-22 | A kind of self-compensating RS485 circuits of optocoupler transmission delay |
Country Status (1)
| Country | Link |
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| CN (1) | CN206515816U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109597783A (en) * | 2018-11-30 | 2019-04-09 | 中国电子科技集团公司第四十八研究所 | A kind of double light-coupled isolation type RS485 circuits |
-
2017
- 2017-02-22 CN CN201720162609.8U patent/CN206515816U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109597783A (en) * | 2018-11-30 | 2019-04-09 | 中国电子科技集团公司第四十八研究所 | A kind of double light-coupled isolation type RS485 circuits |
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