CN203644031U - RS485 signal forwarding device - Google Patents
RS485 signal forwarding device Download PDFInfo
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- CN203644031U CN203644031U CN201320771212.0U CN201320771212U CN203644031U CN 203644031 U CN203644031 U CN 203644031U CN 201320771212 U CN201320771212 U CN 201320771212U CN 203644031 U CN203644031 U CN 203644031U
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- 238000006243 chemical reaction Methods 0.000 abstract description 7
- 230000008878 coupling Effects 0.000 abstract 1
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- 238000010586 diagram Methods 0.000 description 2
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Abstract
The utility model discloses an RS485 signal forwarding device which comprises two groups of RS485 conversion circuits. A serial communication bus output end of each group of RS485 conversion circuits is connected with an RS485 interface, a power circuit provides working power for the RS485 conversion circuits, the serial communication bus output ends of the two groups of RS485 conversion circuits are connected with a power source by pull-up resistors, a data transmitting end of each group of RS485 conversion circuits is connected with a control base electrode of a transistor amplifying circuit by a coupling resistor, an emitting electrode of the transistor amplifying circuit is grounded, a collecting electrode of the transistor amplifying circuit is connected with the power source by a current limiting resistor, and a read-write enable end of each group of RS485 conversion circuits is connected with the collecting electrode of the transistor amplifying circuit. The RS485 signal forwarding device has the advantage that the problem of communication failure due to excessive loads on RS485 buses when a plurality of RS485 devices such as electric energy meters of RS485 interfaces are connected with one another in parallel can be solved.
Description
Technical field
The utility model relates to a kind of signal repeater device, particularly relates to a kind of signal retransmission unit of RS485 communication interface.
Background technology
RS485 communication has a wide range of applications in fields such as electric power, industry, traffic, common as the multifunction electric meter of electric system etc., is generally all equipped with RS485 communication interface.Take the multifunction electric meter of electric system as example, in the time carrying out automatic data logging, if the ammeter equipment connection of multiple RS485 interfaces together time, can be realized easily wiring and communicate by letter with ammeter.And in the time that the ammeter equipment connecting is too much, can produce following defect, and cause the RS485 interface of kilowatt meter recorder can not normally from ammeter equipment, read data because the load in RS485 bus is overweight, affect it and normally use.
Summary of the invention
The problem that the utility model exists for prior art, proposes a kind of RS485 signal retransmission unit.Can solve in the time that multiple RS485 equipment is connected in parallel as the electric energy meter of RS485 interface the problem that cannot communicate by letter causing because the load in RS485 bus is overweight.
The technical scheme that the utility model adopts:
A kind of RS485 signal retransmission unit, contain power circuit, RS485 change-over circuit, RS485 interface, described signal retransmission unit contains two groups of RS485 change-over circuits, the serial communication bus output of each group RS485 change-over circuit connects a RS485 interface, power circuit provides working power for described RS485 change-over circuit, wherein the universal serial bus output terminal of two groups of RS485 change-over circuits all connects power supply by pull-up resistor, wherein the data sending terminal of each group respectively connects the control base stage of a transistor amplifier circuit by a repeating resistance, the grounded emitter of described transistor amplifier circuit, its collector connects power supply by a current-limiting resistance, the read-write Enable Pin of described each group RS485 change-over circuit connects the collector of transistor amplifier circuit.
Described RS485 signal retransmission unit, the data receiver of the data sending terminal of first group of RS485 change-over circuit and second group of RS485 change-over circuit is connected power supply by first current-limiting resistance, forms equipotential and connects; The data sending terminal of the data receiver of first group of RS485 change-over circuit and second group of RS485 change-over circuit is connected power supply by second current-limiting resistance, forms equipotential and connects; The power supply termination power of described each group RS485 change-over circuit, one of its data-in port connects power supply by pull-up resistor, and one by pull down resistor ground connection.
Useful good effect of the present utility model:
The utility model is reasonable in design, and circuit structure is simple, has guaranteed communication reliability when multiple RS485 interfacing equipments connect.After the utility model connects multiple RS485 interfacing equipments, by converting the mode of 1 RS485 interface to, realize and being connected with multiple RS485 interfacing equipments, and can not cause the problem that RS485 bus is overweight due to load and cannot communicate by letter simultaneously.
Accompanying drawing explanation
Fig. 1: the utility model RS485 signal retransmission unit compositional block diagram;
Fig. 2: the utility model RS485 signal retransmission unit circuit theory diagrams.
Embodiment
As shown in Figure 1, the utility model RS485 signal retransmission unit, is mainly made up of power supply, 2 groups of RS485 change-over circuits and 2 RS485 interfaces.Described power circuit provides working power for RS485 change-over circuit.
As shown in Figure 2, wherein the serial communication bus output of each group RS485 change-over circuit connects a RS485 interface, universal serial bus output terminal (the Rxd of two groups of RS485 change-over circuits, Txd) all connect power supply by pull-up resistor, wherein the data sending terminal of each group respectively connects the control base stage of a transistor amplifier circuit by a repeating resistance, the grounded emitter of described transistor amplifier circuit, its collector connects power supply by a current-limiting resistance, and the read-write Enable Pin of each group RS485 change-over circuit connects the collector of transistor amplifier circuit.
The data sending terminal Txd1 of first group of RS485 change-over circuit is connected power Vcc with the data receiver Rxd2 of second group of RS485 change-over circuit by current-limiting resistance R11, forms equipotential and connects; The data receiver Rxd1 of first group of RS485 change-over circuit is connected power supply with the data sending terminal Txd2 of second group of RS485 change-over circuit by current-limiting resistance R12, forms equipotential and connects; The power supply termination power of each group RS485 change-over circuit, its data-in port A1, A2 connects power supply by pull-up resistor, B1, B2 is by pull down resistor ground connection.
In use, after the RS485 interface of one group of RS485 interfacing equipment (as electric energy meter) is connected, be connected as interface 1 with one of them RS485 interface of the utility model signal retransmission unit, using another one RS485 interface (interface 2) as with the communication interface of this group RS485 equipment, like this concerning with the equipment (as kilowatt meter recorder) of upper level, the RS485 bus load of seeing is exactly the load of 1 equipment.After system powers on, the data that RS485 interface 1 is received send by RS485 interface 2, and the data that RS485 interface 2 is received send by RS485 interface 1.
The course of work of described RS485 signaling conversion circuit is as follows:
In the time that numeral 1 need to send to A2, B2 from A1, B1, Txd1 is high level, Q1 conducting, Dir1 is low level, therefore Rxd1(Txd2) be high level.Txd2 is high level, Q2 conducting, and Dir2 is low level, so now U2 is in accepting state.And R8 on draw drop-down with R9, so A2>B2, so now the state of the RS485 bus of A2, B2 is numeral 1.When numeral 0 is need to send to A2, B2 from A1, B1 time, Txd1 is high level, and Q1 conducting, Dir1 is low level, therefore Rxd1(Txd2) be low level, Txd2 is low level, Q2 by, Dir2 is high level, now U2 is in transmission state.Txd2 is low level, so now the RS485 bus state of A2, B2 is numeral 0.Because circuit is symmetrical, in the time that data send A1, B1 from A2, B2, carry out similar process.
Claims (2)
1. a RS485 signal retransmission unit, contain power circuit, RS485 change-over circuit, RS485 interface, it is characterized in that: described signal retransmission unit contains two groups of RS485 change-over circuits, the serial communication bus output of each group RS485 change-over circuit connects a RS485 interface, power circuit provides working power for described RS485 change-over circuit, wherein the universal serial bus output terminal of two groups of RS485 change-over circuits all connects power supply by pull-up resistor, wherein the data sending terminal of each group respectively connects the control base stage of a transistor amplifier circuit by a repeating resistance, the grounded emitter of described transistor amplifier circuit, its collector connects power supply by a current-limiting resistance, the read-write Enable Pin of described each group RS485 change-over circuit connects the collector of transistor amplifier circuit.
2. RS485 signal retransmission unit according to claim 1, it is characterized in that: the data receiver of the data sending terminal of described first group of RS485 change-over circuit and second group of RS485 change-over circuit is connected power supply by first current-limiting resistance, form equipotential and connect; The data sending terminal of the data receiver of first group of RS485 change-over circuit and second group of RS485 change-over circuit is connected power supply by second current-limiting resistance, forms equipotential and connects; The power supply termination power of described each group RS485 change-over circuit, one of its data-in port connects power supply by pull-up resistor, and one by pull down resistor ground connection.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201320771212.0U CN203644031U (en) | 2013-12-01 | 2013-12-01 | RS485 signal forwarding device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201320771212.0U CN203644031U (en) | 2013-12-01 | 2013-12-01 | RS485 signal forwarding device |
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| Publication Number | Publication Date |
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| CN203644031U true CN203644031U (en) | 2014-06-11 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201320771212.0U Expired - Fee Related CN203644031U (en) | 2013-12-01 | 2013-12-01 | RS485 signal forwarding device |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103678232A (en) * | 2013-12-01 | 2014-03-26 | 国家电网公司 | RS485 signal forwarding device |
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2013
- 2013-12-01 CN CN201320771212.0U patent/CN203644031U/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103678232A (en) * | 2013-12-01 | 2014-03-26 | 国家电网公司 | RS485 signal forwarding device |
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Legal Events
| Date | Code | Title | Description |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20140611 Termination date: 20191201 |
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| CF01 | Termination of patent right due to non-payment of annual fee |