CN203911885U - Biasing resistor controllable type 485 communication circuit - Google Patents
Biasing resistor controllable type 485 communication circuit Download PDFInfo
- Publication number
- CN203911885U CN203911885U CN201420357607.0U CN201420357607U CN203911885U CN 203911885 U CN203911885 U CN 203911885U CN 201420357607 U CN201420357607 U CN 201420357607U CN 203911885 U CN203911885 U CN 203911885U
- Authority
- CN
- China
- Prior art keywords
- biasing resistor
- control signal
- channel mos
- circuit
- con
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 238000004891 communication Methods 0.000 title claims abstract description 19
- 230000008878 coupling Effects 0.000 claims abstract description 15
- 238000010168 coupling process Methods 0.000 claims abstract description 15
- 238000005859 coupling reaction Methods 0.000 claims abstract description 15
- 230000002093 peripheral effect Effects 0.000 claims abstract description 8
- 230000005540 biological transmission Effects 0.000 claims description 5
- 102100028680 Protein patched homolog 1 Human genes 0.000 claims description 2
- 101710161390 Protein patched homolog 1 Proteins 0.000 claims description 2
- 238000000034 method Methods 0.000 abstract description 3
- 239000004065 semiconductor Substances 0.000 description 2
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 230000001052 transient effect Effects 0.000 description 1
Landscapes
- Amplifiers (AREA)
Abstract
The utility model relates to a biasing resistor controllable type 485 communication circuit which comprises a signal photoelectric coupling circuit, a biasing resistor control signal reverse circuit, and a 485 chip and peripheral circuits thereof. The 485 chip A communication interface is connected with the drain of a P-channel MOS transistor through a first resistor. The source of the P-channel MOS transistor is connected with a power source. The gate of the P-channel MOS transistor is used as the biasing resistor control signal input end. According to the utility model, the method in which an electronic switch and an ordinary biasing resistor are serially connected is adopted, so the biasing resistor of a node can be switched between an infinite biasing resistor and an ordinary biasing resistor, and the biasing resistor of a 485 bus is changed through the change of the control signal, so that the circuit is compatible with polar and nonpolar electric energy meters of the national grid at the same time, and advantages of easy and convenient operation, low cost and good practicability can be realized.
Description
Technical field
The utility model relates to a kind of 485 telecommunication circuits, is specifically related to 485 controlled telecommunication circuits of a kind of biasing resistor.
Background technology
Biasing resistor in 485 telecommunication circuits provides an idle level reliably for bus, and in two-wire system 485 telecommunication circuits, biasing resistor also will coordinate the saltus step of 485 buses from " 0 " to " 1 " especially.Along with the development of intelligent grid centralized meter-reading system, non-polar 485 chip, owing to not needing manual identified A, B, has started to be applied in intelligent electric energy meter.In non-polar 485 electric energy meters, do not exist biasing resistor or biasing resistor very large, and in having polarity 485 electric energy meters, have the biasing resistor of 10K ~ 30K.485 circuit of kilowatt meter recorder, when nonpolarity 485 electric energy meter of copy reading, biasing resistor should be as much as possible little, to guarantee enough bus driver abilities; And copy reading is while having polarity 485 electric energy meter, biasing resistor should be large as much as possible, reduces the load of bus.Therefore require the biasing resistor of kilowatt meter recorder adjustable, and kilowatt meter recorder is not being revised under the condition of hardware at present, is difficult to accomplish compatible when first two electric energy meter.
Summary of the invention
For the problems referred to above the utility model, provide a kind of 485 controlled telecommunication circuits of biasing resistor that are applied to kilowatt meter recorder, simultaneously compatible national grid has polarity and a nonpolarity electric energy meter.
For addressing the above problem, the utility model provides 485 controlled telecommunication circuits of a kind of biasing resistor: comprise flashlight electric coupling circuit, biasing resistor control signal negater circuit and 485 chips and peripheral circuit thereof, 485 described chip A communication interfaces connect the drain electrode of P channel MOS tube through the first resistance, the source electrode of P channel MOS tube connects power supply, and grid is as biasing resistor control signal input; 485 described chip B communication interfaces connect the drain electrode of N-channel MOS pipe through the second resistance, the source ground of N-channel MOS pipe, grid is as biasing resistor reverse control signal input, and biasing resistor reverse control signal is converted through biasing resistor control signal negater circuit by biasing resistor control signal.The method of using electronic switch to connect with common biasing resistor, utilize the infinitely-great feature of pass resistance break of electronic switch, the biasing resistor of node can be switched between infinitely great and common biased electrical resistance, so that compatible national grid has polarity and a nonpolarity electric energy meter simultaneously.
For the conducting simultaneously of two kinds of metal-oxide-semiconductors or the shutoff that guarantees to be connected with A, B communication interface respectively, while needing therein an a certain control signal of input, another inputs reverse control signal, so need realize by biasing resistor control signal negater circuit.At this, described biasing resistor control signal negater circuit is such: control signal is by the base stage of the 3rd resistance input triode, and the collector electrode output reverse control signal of triode also connects power supply by pull-up resistor, its grounded emitter.
This telecommunication circuit need be converted to the control signal from external control unit by photoelectric coupling circuit the control signal of 485 chips, controls the work of 485 chips.Described photoelectric coupling circuit comprises three coupling circuits, be connected with data reception signal output, reception Enable Pin and the transmission Enable Pin and data transmitted signal input of 485 chips respectively, also comprise that a coupling circuit is transferred to control signal the control signal input of 485 peripheral circuits.
Signal MCU485R_D forms signal 485R_D after driving optocoupler O1, is the transmitting-receiving control signal of RS485 chip, and the transmitting-receiving that completes RS485 data enables.
Signal MCUTx485Rx forms signal 485_D after driving optocoupler O2, is data transmitted signal, completes the transmission of RS485 data.
Signal MCUR_CON forms signal 485_CON after driving optocoupler O3, is biasing resistor control signal; / 485_CON is the reverse signal of 485_CON.
Signal 485_R forms signal MCURx485Tx after driving optocoupler O4, is data reception signal, completes the reception of RS485 data.
Signal MCUR-CON is 1 o'clock, optocoupler cut-off, and the control signal input 485-CON of 485 chips is set to 1, P channel MOS tube Q1 cut-off; Control signal reverse input end/485-CON is reversed 0 simultaneously, N-channel MOS pipe Q2 cut-off, and now biasing resistor is equivalent to the pass resistance break of metal-oxide-semiconductor, is infinity, is now applicable to and has polarity ammeter to communicate.Signal MCUR-CON is 0 o'clock, and optocoupler is saturated, and the control signal input 485-CON of 485 chips is set to 0, P channel MOS tube Q1 conducting; Control signal reverse input end/485-CON is reversed 1 simultaneously, N-channel MOS pipe Q2 conducting, and now biasing resistor is equivalent to R9, R10, is now applicable to communicating with nonpolarity ammeter.
485 chip A communication interfaces and B communication interface are respectively by a TVS pipe ground connection, and B communication interface is connected to a thermistor.Described TVS pipe can weaken the intensity of pulse signal, enters the transient voltage of 485 chips, thereby can protect 485 chips thereby reduce pulse signal, prevents that 485 chips are damaged, and reliability is high.The effect of thermistor is that when continuation over-voltage and over-current, thermistor resistance increases rapidly in order to prevent continuation over-voltage and over-current, is equivalent to open circuit, and when electric current and voltage recovers normal, thermistor resistance also returns to normal little resistance.
The method that the utility model is used electronic switch to connect with common biasing resistor, the biasing resistor of node can be switched between infinitely great and common biasing resistor, by the variation of control signal, change the biasing resistor of 485 buses, thereby simultaneously compatible national grid has polarity and a nonpolarity electric energy meter, simple to operation, with low cost, practical.
Accompanying drawing explanation
Fig. 1 is flashlight electric coupling circuit figure;
Fig. 2 is biasing resistor control signal negater circuit figure;
Fig. 3 is 485 chips and peripheral circuit diagram thereof.
Embodiment
As shown in Figure 1,485 telecommunication circuits that a kind of biasing resistor is controlled, comprise flashlight electric coupling circuit, biasing resistor control signal negater circuit and 485 chips and peripheral circuit thereof, 485 described chip A communication interfaces connect the drain electrode of P channel MOS tube Q1 through the first resistance R 9, the source electrode of P channel MOS tube Q1 meets power supply V485, and grid is as biasing resistor control signal input 485-CON; 485 described chip B communication interfaces connect the drain electrode of N-channel MOS pipe Q2 through the second resistance R 10, the source ground G485 of N-channel MOS pipe Q2, grid is as biasing resistor reverse control signal input/485-CON, and the second described resistance R 10 and the first resistance R 9 resistances are 1 kilo-ohm.485 chip A communication interfaces and B communication interface are respectively by TVS pipe TVS1, a TVS2 ground connection G485, and B communication interface is connected to a thermistor PTC1.Biasing resistor reverse control signal is converted through biasing resistor control signal negater circuit by biasing resistor control signal.Described biasing resistor control signal negater circuit is such: control signal 485-CON is by the base stage of the 3rd resistance R 12 input triode Q3, collector electrode output reverse control signal/485-CON of triode Q3 also connects power supply V485, its grounded emitter by pull-up resistor R11.Described photoelectric coupling circuit comprises three coupling circuits, be connected with transmission Enable Pin DE and data transmitted signal input D with data reception signal output R, the reception Enable Pin/RE of 485 chips respectively, also comprise that a coupling circuit is transferred to control signal the control signal input 485-CON of 485 peripheral circuits.Signal MCU485R_D forms signal 485R_D after driving optocoupler O1, is the transmitting-receiving control signal of RS485 chip, and the transmitting-receiving that completes RS485 data enables.
Signal MCUTx485Rx forms signal 485_D after driving optocoupler O2, is data transmitted signal, completes the transmission of RS485 data.Signal MCUR_CON forms signal 485_CON after driving optocoupler O3, is biasing resistor control signal; / 485_CON is the reverse signal of 485_CON.
Signal 485_R forms signal MCURx485Tx after driving optocoupler O4, is data reception signal, completes the reception of RS485 data.
Claims (4)
1. 485 telecommunication circuits that biasing resistor is controlled, it is characterized in that: comprise flashlight electric coupling circuit, biasing resistor control signal negater circuit and 485 chips and peripheral circuit thereof, 485 described chip A communication interfaces connect the drain electrode of P channel MOS tube (Q1) through the first resistance (R9), the source electrode of P channel MOS tube (Q1) connects power supply (V485), and grid is as biasing resistor control signal input (485-CON); 485 described chip B communication interfaces connect the drain electrode of N-channel MOS pipe (Q2) through the second resistance (R10), the source ground (G485) of N-channel MOS pipe (Q2), grid is as biasing resistor reverse control signal input (/ 485-CON), and biasing resistor reverse control signal is converted through biasing resistor control signal negater circuit by biasing resistor control signal.
2. 485 controlled telecommunication circuits of biasing resistor according to claim 1, it is characterized in that: described biasing resistor control signal negater circuit is such: control signal (485-CON) is by the base stage of the 3rd resistance (R12) input triode (Q3), the collector electrode output reverse control signal (/ 485-CON) of triode (Q3) also connects power supply (V485), its grounded emitter by pull-up resistor (R11).
3. 485 controlled telecommunication circuits of biasing resistor according to claim 1 and 2, it is characterized in that: described photoelectric coupling circuit comprises three coupling circuits, be connected with data reception signal output (R), reception Enable Pin (/RE) and the transmission Enable Pin (DE) and data transmitted signal input (D) of 485 chips respectively, also comprise that a coupling circuit is transferred to control signal the control signal input (485-CON) of 485 peripheral circuits.
4. 485 controlled telecommunication circuits of biasing resistor according to claim 1 and 2, it is characterized in that: 485 chip A communication interfaces and B communication interface are respectively by TVS pipe (TVS1, a TVS2) ground connection (G485), and B communication interface is connected to a thermistor (PTC1).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420357607.0U CN203911885U (en) | 2014-07-01 | 2014-07-01 | Biasing resistor controllable type 485 communication circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420357607.0U CN203911885U (en) | 2014-07-01 | 2014-07-01 | Biasing resistor controllable type 485 communication circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN203911885U true CN203911885U (en) | 2014-10-29 |
Family
ID=51786127
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201420357607.0U Expired - Lifetime CN203911885U (en) | 2014-07-01 | 2014-07-01 | Biasing resistor controllable type 485 communication circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN203911885U (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109274615A (en) * | 2018-11-09 | 2019-01-25 | 珠海格力电器股份有限公司 | Bus signal reflection suppression method, device and system and control circuit |
| CN109560967A (en) * | 2018-12-18 | 2019-04-02 | 珠海格力电器股份有限公司 | Master-slave machine switching circuit and circuit control method |
| CN112117990A (en) * | 2020-09-16 | 2020-12-22 | 珠海格力电器股份有限公司 | Communication apparatus and control method thereof |
-
2014
- 2014-07-01 CN CN201420357607.0U patent/CN203911885U/en not_active Expired - Lifetime
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109274615A (en) * | 2018-11-09 | 2019-01-25 | 珠海格力电器股份有限公司 | Bus signal reflection suppression method, device and system and control circuit |
| CN109274615B (en) * | 2018-11-09 | 2020-01-31 | 珠海格力电器股份有限公司 | Bus signal reflection suppression method, device and system and control circuit |
| CN109560967A (en) * | 2018-12-18 | 2019-04-02 | 珠海格力电器股份有限公司 | Master-slave machine switching circuit and circuit control method |
| CN112117990A (en) * | 2020-09-16 | 2020-12-22 | 珠海格力电器股份有限公司 | Communication apparatus and control method thereof |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN107065716B (en) | Digital quantity acquisition circuit with dynamic fault diagnosis capability | |
| CN204929366U (en) | DALI interface circuit | |
| CN205490115U (en) | Switching power supply circuit | |
| CN203911885U (en) | Biasing resistor controllable type 485 communication circuit | |
| CN203225733U (en) | A single-channel bidirectional logic level converter | |
| CN209526709U (en) | A kind of bidirectional level conversion circuit and two-way level converting chip | |
| CN103051325B (en) | Pull-up resistance circuit for preventing reverse current filling | |
| CN204180045U (en) | Based on the serial port level chance-over circuit of the intellectual education terminal of Internet of Things | |
| CN103746681A (en) | Power-on/power-down output tri-state control circuit for CMOS device power supply | |
| CN102307010A (en) | Data transmission voltage conversion circuit | |
| CN108134518B (en) | Voltage conversion circuit | |
| CN103501173A (en) | Pull-up resistor circuit for preventing inverse current transmission and input-output port circuit | |
| CN215419641U (en) | Communication system | |
| CN214756076U (en) | MOS pipe control circuit and device | |
| CN102231930B (en) | Light-control digital interface circuit | |
| CN105846809B (en) | A kind of buffer circuit and buffer chip | |
| CN203537553U (en) | An Interface circuit realizing serial port and infrared multiplex functions | |
| CN104764924A (en) | High-voltage MOSFET current sampling circuit | |
| CN209572001U (en) | A kind of driving circuit and level shifting circuit of signal transfer tube | |
| CN204304165U (en) | Usb adapter | |
| CN106533875A (en) | RS485 line selector circuit | |
| CN203761362U (en) | Bidirectional interface circuit | |
| CN204633748U (en) | 3.3V and 5V device bidirectional communication circuit of mixed voltage power supply system | |
| CN207782386U (en) | One kind preventing leakage circuit after chip power-down | |
| CN109449915A (en) | Circuit is protected in built-in miniaturization suitable for the power-up out of order of TR component |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CX01 | Expiry of patent term |
Granted publication date: 20141029 |