CN204392241U

CN204392241U - A kind of novel RS485 communicating circuit

Info

Publication number: CN204392241U
Application number: CN201520074854.4U
Authority: CN
Inventors: 江建明
Original assignee: Individual
Current assignee: Individual
Priority date: 2015-02-03
Filing date: 2015-02-03
Publication date: 2015-06-10
Anticipated expiration: 2025-02-03

Abstract

The utility model is in order to solve communication line problem involved in background technology, propose a kind of novel RS485 communicating circuit, it is characterized in that: comprise the transceiver module, isolation module and the current limliting filtration module that connect successively, described transceiver module comprises RS485 chip U1 and chip periphery circuit, it has the input connecting RS485 circuit, and the output be connected with described isolation module; Described isolation module has the source class end be connected with described transceiver module, and the secondary end be connected with described current limliting filtration module; Described current limliting filtration module receives the signal that described secondary end exports, after current limliting filtering process, export subsequent conditioning circuit to.The utility model has the advantages such as circuit theory is simple, antijamming capability is strong, is suitable for promoting the use of in power monitoring terminal.

Description

A kind of novel RS485 communicating circuit

Technical field

The utility model relates to a kind of novel RS485 communicating circuit.

Background technology

Electric power management system terminal is information gathering based on Computer Applied Technology, modern communication technology, power auto-control technology, process and real-time monitoring system.

In prior art, the management of power use of terminal use is the form adopting " multifunction electric meter+electric power management system terminal ", multifunction electric meter is utilized to measure electricity consumption situation, monitored by the ruuning situation of electrical management terminal to multifunction electric meter again, realize by cordless communication network the related system that Monitoring Data is dealt into power office, whether whether the electricity consumption situation that office side just judges electricity consumption scene according to these real time datas normal, normal etc. for the multifunction electric meter work of measuring.

The abnormal conditions such as CT short circuit, open circuit can be there are in electricity consumption scene, electricity so not only can be caused to leak meter, bring loss to power office, and not predictable danger can be brought.And the interference in present power grid environment is a lot, a lot of harmonic waves is there is in electrical network, very high to the performance requirement of electricity load management terminal so in fact, because the effect of what it played in this system in fact is a standard scale and human observer, and relevant detection data will be transferred to wireless communication networks by it, so be quite high to the requirement of its reliability, particularly at frequency collection, the requirement of quantity of state collection aspect is all higher, current electrical management terminal meter precision is poor, long-play is reliable and stable not, data acquisition poor anti jamming capability, can not accurately report CT short circuit, open circuit abnormal conditions.

When optocoupler is through overaging in current RS485 communicating circuit, or during long-time outside harsh, there will be optocoupler current transfer ratio CTR and diminish, Ic diminishes, optocoupler Vce becomes large, has exceeded processor TTL low level maximum, there will be the problem of Communications failure in high bit rate situation.

Utility model content

In order to solve communication line problem involved in background technology, the utility model provides the novel RS485 communicating circuit that a kind of circuit theory is simple, antijamming capability is strong, and its technical scheme adopted is as follows:

A kind of novel RS485 communicating circuit, comprise the transceiver module, isolation module and the current limliting filtration module that connect successively, described transceiver module comprises RS485 chip U1 and chip periphery circuit, and it has the input connecting RS485 circuit, and the output be connected with described isolation module; Described isolation module has the source class end be connected with described transceiver module, and the secondary end be connected with described current limliting filtration module; Described current limliting filtration module receives the signal that described secondary end exports, after current limliting filtering process, export subsequent conditioning circuit to.

Preferably implement as the utility model, described isolation module comprises optical coupling unit U2, current-limiting resistance R8 and pull-up resistor R9, the anode tap Anode of described optical coupling unit U2 is connected with the output of described transceiver module by current-limiting resistance R8, described pull-up resistor R9 one end connects forward height ordinary telegram, and the other end connects described anode tap Anode; The vdd terminal of described optical coupling unit U2 is as the output of isolation module.

Preferably implement as the utility model, the differential input end A of the RS485 circuit that described RS485 chip U1 tool connects and differential input end B, described differential input end A receives the forward differential signal of RS485 circuit, and described differential input end B receives the negative sense differential signal of RS485 circuit; Wherein, described differential input end A is connected to low level through a pull-up resistor R4, and described differential input end B is connected to COM port through a pull-up resistor R3.

Preferably implement as the utility model, described RS485 chip has data output end RD, data output end DI, and controls the first Enable Pin RE that described data output end RD works, the second Enable Pin DE controlling described data input pin DI work.

Preferably implement as the utility model, described current limliting filtration module comprises current-limiting resistance R1 and R16, biasing resistor R5 and R7, triode Q1, magnetic bead L1, speed-up capacitor C1 and filter capacitor C3, the base stage of described triode Q1 is connected with the output of described isolation module by described current-limiting resistance R16, described current-limiting resistance R16 is parallel with speed-up capacitor C1, described biasing resistor R5 and R7 is connected in series between forward high level and ground, and both points of contact are connected with the base stage of described triode pipe; The collector electrode of described triode Q1 connects one end of described current-limiting resistance R1, magnetic bead L1 respectively, and the other end of described current-limiting resistance R1 and magnetic bead L1 is connected to the output of current limliting filtration module; The grounded emitter of described triode Q1; The output of described current limliting filtration module is connected to filter capacitor C3.

Advantageous of the present utility model exists:

1) in current limliting filtration module of the present utility model, current-limiting resistance R16 two ends are also connected to speed-up capacitor C1, the response speed of circuit when speed-up capacitor C1 can ensure signal high-speed transfer.

2) isolation module of the present utility model adopts the mode of light-coupled isolation, receiving and transmitting signal is converted to stable RS485 signal and exports, and the RS485 achieved truly isolates communication.

Accompanying drawing explanation

Fig. 1 is principle framework schematic diagram of the present utility model.

Fig. 2 is electrical block diagram of the present utility model.

Embodiment

As follows by reference to the accompanying drawings, the application's scheme is further described:

As shown in Figure 1-2, a kind of novel RS485 communicating circuit, comprise the transceiver module 10, isolation module 20 and the current limliting filtration module 30 that connect successively, described transceiver module 10 comprises RS485 chip U1 and chip periphery circuit, it has the input connecting RS485 circuit, and the output be connected with described isolation module 20; Described isolation module 20 has the source class end be connected with described transceiver module 10, and the secondary end be connected with described current limliting filtration module 30; Described current limliting filtration module 30 receives the signal that described secondary end exports, after current limliting filtering process, export subsequent conditioning circuit to.

Described isolation module 20 comprises optical coupling unit U2, current-limiting resistance R8 and pull-up resistor R9, the anode tap Anode of described optical coupling unit U2 is connected with the output of described transceiver module 10 by current-limiting resistance R8, described pull-up resistor R9 one end connects forward height ordinary telegram, and the other end connects described anode tap Anode; The vdd terminal of described optical coupling unit U2 is as the output of isolation module 20, and this input and ground are connected to resistance R6 between hold, and the GND of optical coupling unit U2 holds and is connected to COM port.

The differential input end A of the RS485 circuit that described RS485 chip U1 tool connects and differential input end B, described differential input end A receives the forward differential signal of RS485 circuit, and described differential input end B receives the negative sense differential signal of RS485 circuit; Wherein, described differential input end A is connected to low level through a pull-up resistor R4, and described differential input end B is connected to COM port through a pull-up resistor R3, and the VCC termination of RS485 chip enters high level, and GND end is connected to COM port.

Described RS485 chip has data output end RD, data output end DI, and controls the first Enable Pin RE that described data output end RD works, the second Enable Pin DE controlling described data input pin DI work.

Described current limliting filtration module 30 comprises current-limiting resistance R1 and R16, biasing resistor R5 and R7, triode Q1, magnetic bead L1, speed-up capacitor C1 and filter capacitor C3, the base stage of described triode Q1 is connected with the output of described isolation module 20 by described current-limiting resistance R16, described current-limiting resistance R16 is parallel with speed-up capacitor C1, described biasing resistor R5 and R7 is connected in series between forward high level and ground, and both points of contact are connected with the base stage of described triode pipe; The collector electrode of described triode Q1 connects one end of described current-limiting resistance R1, magnetic bead L1 respectively, and the other end of described current-limiting resistance R1 and magnetic bead L1 is connected to the output of current limliting filtration module 30; The grounded emitter of described triode Q1; The output of described current limliting filtration module 30 is connected to filter capacitor C3.

Such scheme achieves: outside RS485 differential signal is converted into Transistor-Transistor Logic level through RS485 chip U1, Transistor-Transistor Logic level is through light-coupled isolation incoming terminal receiving terminal, signal is carried out isolation transmission by it, improve electric power terminal management system antijamming capability, simultaneously in isolation module optical coupler photoelectric coupled circuit transfer ratio CTR diminish after communication unaffected.

Above-mentioned preferred implementation should be considered as illustrating of the application's scheme implementation mode, allly to duplicate with the application's scheme, technology that is approximate or that make based on this is deduced, replaces, improvement etc., all should be considered as the protection range of this patent.

Claims

1. a novel RS485 communicating circuit, it is characterized in that: comprise the transceiver module, isolation module and the current limliting filtration module that connect successively, described transceiver module comprises RS485 chip U1 and chip periphery circuit, it has the input connecting RS485 circuit, and the output be connected with described isolation module; Described isolation module has the source class end be connected with described transceiver module, and the secondary end be connected with described current limliting filtration module; Described current limliting filtration module receives the signal that described secondary end exports, after current limliting filtering process, export subsequent conditioning circuit to.

2. novel RS485 communicating circuit according to claim 1, it is characterized in that: described isolation module comprises optical coupling unit U2, current-limiting resistance R8 and pull-up resistor R9, the anode tap Anode of described optical coupling unit U2 is connected with the output of described transceiver module by current-limiting resistance R8, described pull-up resistor R9 one end connects forward height ordinary telegram, and the other end connects described anode tap Anode; The vdd terminal of described optical coupling unit U2 is as the output of isolation module.

3. novel RS485 communicating circuit according to claim 1 and 2, it is characterized in that: the differential input end A of the RS485 circuit that described RS485 chip U1 tool connects and differential input end B, described differential input end A receives the forward differential signal of RS485 circuit, and described differential input end B receives the negative sense differential signal of RS485 circuit; Wherein, described differential input end A is connected to low level through a pull-up resistor R4, and described differential input end B is connected to COM port through a pull-up resistor R3.

4. novel RS485 communicating circuit according to claim 3, it is characterized in that: described RS485 chip has data output end RD, data output end DI, and control the first Enable Pin RE that described data output end RD works, the second Enable Pin DE controlling described data input pin DI work.

5. novel RS485 communicating circuit according to claim 3, it is characterized in that: described current limliting filtration module comprises current-limiting resistance R1 and R16, biasing resistor R5 and R7, triode Q1, magnetic bead L1, speed-up capacitor C1 and filter capacitor C3, the base stage of described triode Q1 is connected with the output of described isolation module by described current-limiting resistance R16, described current-limiting resistance R16 is parallel with speed-up capacitor C1, described biasing resistor R5 and R7 is connected in series between forward high level and ground, and both points of contact are connected with the base stage of described triode pipe; The collector electrode of described triode Q1 connects one end of described current-limiting resistance R1, magnetic bead L1 respectively, and the other end of described current-limiting resistance R1 and magnetic bead L1 is connected to the output of current limliting filtration module; The grounded emitter of described triode Q1; The output of described current limliting filtering mould module is connected to filter capacitor C3.