CN207557390U

CN207557390U - MBUS bus short circuit detection circuits

Info

Publication number: CN207557390U
Application number: CN201721743723.6U
Authority: CN
Inventors: 贺驰光; 汤可
Original assignee: Wasion Information Technology Ltd By Share Ltd
Current assignee: Wasion Information Technology Ltd By Share Ltd
Priority date: 2017-12-14
Filing date: 2017-12-14
Publication date: 2018-06-29
Anticipated expiration: 2027-12-14

Abstract

The utility model discloses a kind of MBUS bus short circuits detection circuit, including the bus voltage detection circuit being sequentially connected in series and bus state decision circuitry；Bus voltage detection circuit judges the voltage and output drive signal between the signal wire of MBUS buses, and bus state decision circuitry exports the short-circuit detecting consequential signal of MBUS buses according to drive signal.The utility model is realized the short-circuit detecting of MBUS buses by simple and reliable circuit, can not only detect the short-circuit conditions of MBUS buses in real time, and circuit is simple and reliable according to the voltage difference relationship between the signal wires of MBUS buses.

Description

MBUS bus short circuit detection circuits

Technical field

The utility model is specifically related to a kind of MBUS bus short circuits detection circuit.

Background technology

With the development and the improvement of people's living standards of national economy technology, bus communication technology has become industry Essential means of communication in production and electric/electronic device.MBUS buses are widely used in the meterings such as water meter, ammeter or gas meter In instrument, the important function of data communication is carry, therefore the status monitoring of MBUS buses is just particularly important.

Working condition that there are three types of MBUS buses, respectively short circuit are normally powered on and are not powered.According to national grid multilist collection Copy the requirement of technical specification, the normal of MBUS buses powers on or non-power supply state is regarded as MBUS normal conditions, and MBUS is total Line short-circuit condition then regards as abnormality, needs to detect, find and handle in time.

At present, for MBUS bus states monitoring technology have more research, but do not find there are can reliably, Quickly it can simply detect the circuit that the short-circuit condition of MBUS buses is detected.

Utility model content

The short-circuit condition of MUBS buses can be quickly detected, and simply may be used the purpose of this utility model is to provide a kind of The MBUS bus short circuit detection circuits leaned on.

This MBUS bus short circuits detection circuit provided by the utility model, the bus voltage including being sequentially connected in series detect electricity Road and bus state decision circuitry；The signal wire of the input terminal connection MBUS buses of bus voltage detection circuit, bus voltage inspection The input terminal of the output terminal connection bus state decision circuitry of slowdown monitoring circuit；The output terminal output kind MBUS buses of bus decision circuitry The consequential signal of short-circuit detecting；Bus voltage detection circuit judges the voltage between the signal wire of MBUS buses and output driving letter Number to bus state decision circuitry, bus state decision circuitry is according to the short circuit inspection of drive signal output MBUS buses received Survey consequential signal.

The MBUS bus short circuit detection circuits further include isolation circuit；Isolation circuit is connected to bus state and judges electricity The output terminal on road, the signal for bus state decision circuitry to be exported are delivered to late-class circuit again after carrying out electrical isolation.

The isolation circuit is optical coupling isolation circuit.

The bus voltage detection circuit includes pull down resistor, first switch pipe, the first current-limiting resistance, input pull-up electricity Resistance and output pull-up resistor；The anode circuit of MBUS buses connects positive pole signal by inputting pull-up resistor, while also leads to Cross the control terminal of the first current-limiting resistance connection first switch pipe, the cathode of movable end one end connection MBUS buses of first switch pipe Circuit also connects earth signal by pull down resistor；The movable end other end of first switch pipe is defeated for bus voltage detection circuit Outlet, simultaneously also by output pull-up resistor connection positive pole signal.

The bus state decision circuitry includes second switch pipe, the second current-limiting resistance and the second output pull-up resistor； The drive signal of bus voltage detection circuit output connects the control terminal of second switch pipe by the second current-limiting resistance；Second switch The cathode traces of movable end one end connection MBUS buses of pipe, the movable end other end of second switch pipe judge electricity for bus state Road also connects positive pole signal by the second output pull-up resistor.

The first switch pipe and second switch pipe are triode or metal-oxide-semiconductor.

This MBUS bus short circuits detection circuit provided by the utility model, according to the electricity between the signal wire of MBUS buses Pressure difference relationship realizes the short-circuit detecting of MBUS buses by simple and reliable circuit, can not only detect MBUS in real time The short-circuit conditions of bus, and circuit is simple and reliable.

Description of the drawings

Fig. 1 is the functional block diagram of the MBUS bus short circuit detection circuits of the utility model.

Fig. 2 is the circuit diagram of the MBUS bus short circuit detection circuits of the utility model.

Specific embodiment

Functional block diagram for the MBUS bus short circuit detection circuits of the utility model as shown in Figure 1：The utility model carries This MBUS bus short circuits detection circuit supplied, including bus voltage detection circuit, the bus state decision circuitry being sequentially connected in series And isolation circuit；Bus voltage detection circuit input terminal connection MBUS buses signal wire, bus voltage detection circuit it is defeated Outlet connects the input terminal of bus state decision circuitry；The output terminal output kind MBUS bus short circuit detections of bus decision circuitry Consequential signal；Bus voltage detection circuit judges the voltage between the signal wire of MBUS buses and output drive signal is to total linear State decision circuitry, bus state decision circuitry are believed according to the short-circuit detecting result of drive signal output MBUS buses received Number；Isolation circuit is connected to the output terminal of bus state decision circuitry, for by the signal that bus state decision circuitry exports into It is delivered to late-class circuit again after row electrical isolation, so as to ensure the safety of late-class circuit.

It is illustrated in figure 2 the circuit diagram of the MBUS bus short circuit detection circuits of the utility model：Bus voltage in figure Detection circuit includes pull down resistor R8, first switch pipe V1, the first current-limiting resistance R3, input pull-up resistor R1, input protection two Pole pipe V3 and output pull-up resistor R2；Bus state decision circuitry includes second switch pipe V2, the second current-limiting resistance R4 and second Export pull-up resistor R5；Isolation circuit includes opto-coupler chip D1, optocoupler current-limiting resistance R6 and optocoupler output pull-up resistor R7.MBUS The anode circuit MBUS+ of bus connects positive pole signal V5P0_ by inputting protection diode V3 with input pull-up resistor R1 ISO, simultaneously also by the control terminal (base stage of triode V1) of the first current-limiting resistance R3 connection first switch pipes V1, first switch The cathode circuit MBUS- of movable end one end (emitter of triode V1) connection MBUS buses of pipe, also passes through pull down resistor R8 Connect earth signal；The movable end other end (collector of triode V1) of first switch pipe is the output of bus voltage detection circuit End, simultaneously also by output pull-up resistor R2 connection positive pole signals V5P0_ISO；The drive of bus voltage detection circuit output Dynamic control terminal (base stage of triode V2) of the signal by the second current-limiting resistance R4 connection second switch pipes；The work of second switch pipe Moved end one end (emitter of triode V2) connects the cathode traces of MBUS buses, the movable end other end (three of second switch pipe The collector of pole pipe V2) be bus state decision circuitry output terminal, also by the second output pull-up resistor R5 connections power supply just Pole signal.

The course of work of foregoing circuit is as follows：

1) voltage between about 20~42V is had when MBUS buses normally work on power, between MBUS+ and MBUS-, this A voltage value is loaded directly by resistance R3 between the base stage of triode and collector so that the emitter sum aggregate of triode V1 Electrode conduction (at this point, the effect of diode V3 is one-way conduction, so as to ensure the high voltage on MBUS+ circuits may not flow into+ 5V power supply signals end (V5P0_ISO)), the collector voltage of triode V1 is pulled down resistance R8 and is pulled low to MBUS- circuits at this time Level has no voltage difference at this time between the base stage of triode V2 and collector, the emitter and collector of triode V2 is simultaneously at this time It does not turn on, 2 foot of optocoupler is equally pulled to high level by resistance R5 at this time, and the luminous tube of optocoupler will not be connected at this time, therefore light The level signal OVER_LOAD signals of the output pin 4 of coupling are drawn high by resistance R7 to high level, then MBUS bus short circuits at this time The output signal of detection circuit is high level.

2) when MBUS buses do not power on, MBUS+ and MBUS- is without level signal at this time；At this point, the base stage of triode V1 It is drawn high by resistance R1 and R3 to high level, the emitter of triode V1 is pulled low to low level by resistance R8, therefore triode V1 Emitter and collector can equally be connected, and have no voltage difference between the base stage of triode V2 and collector at this time, at this time triode The emitter and collector of V2 does not turn on still, and 2 foot of optocoupler is equally pulled to high level by resistance R5 at this time, at this time the hair of optocoupler Light pipe will not be connected, therefore the level signal OVER_LOAD signals of the output pin 4 of optocoupler draw high supreme electricity by resistance R7 Flat, then the output signal of MBUS bus short circuit detection circuits at this time is high level.

3) when MBUS bus short circuits, short circuit between MBUS+ and MBUS- at this time, the base stage of triode V1 is by resistance at this time R8 is pulled low to low level, and the emitter of triode V1 is also pulled low to the low level (base stage and current collection of triode at this time by resistance R8 Extremely directly it is shorted together), the emitter and collector of triode V1 does not turn at this time；Therefore, the base stage quilt of triode V2 Resistance R2 and R4 are drawn high to high level, and the emitter of triode V2 is pulled low to low level by resistance R8, at this time triode V2 Emitter and collector is connected, at this point, 2 feet of optocoupler are pulled low to low level by resistance R8,1 foot of optocoupler by resistance R6 draw high to High level, the luminous tube conducting of optocoupler at this time shines, therefore 3 foot of reception pipe of optocoupler and the conducting of 4 feet, therefore MBUS bus short circuits The output signal OVER_LOAD of detection circuit directly with ground short circuit, therefore the output signal of MBUS bus short circuit detection circuits OVER_LOAD is low level.

In summary, it is only necessary to according to the level state of the output signal OVER_LOAD of MBUS bus short circuit detection circuits It can determine whether MBUS buses are short-circuit；As long as the output signal OVER_LOAD signals of MBUS bus short circuit detection circuits are low Level signal, then it is short-circuit condition to show MBUS buses.

Claims

1. a kind of MBUS bus short circuits detection circuit, it is characterised in that including the bus voltage detection circuit being sequentially connected in series and bus Status determination circuit；The signal wire of the input terminal connection MBUS buses of bus voltage detection circuit, bus voltage detection circuit Output terminal connects the input terminal of bus state decision circuitry；The output terminal output kind MBUS bus short circuit detections of bus decision circuitry Consequential signal；Bus voltage detection circuit judges the voltage between the signal wire of MBUS buses and output drive signal is to bus Status determination circuit, bus state decision circuitry are believed according to the short-circuit detecting result of drive signal output MBUS buses received Number.

2. MBUS bus short circuits detection circuit according to claim 1, it is characterised in that further include isolation circuit；Isolation electricity Road is connected to the output terminal of bus state decision circuitry, and the signal for bus state decision circuitry to be exported carries out electrical isolation It is delivered to late-class circuit again afterwards.

3. MBUS bus short circuits detection circuit according to claim 2, it is characterised in that the isolation circuit is optocoupler Isolation circuit.

4. the MBUS bus short circuit detection circuits according to one of claims 1 to 3, it is characterised in that the bus voltage Detection circuit includes pull down resistor, first switch pipe, the first current-limiting resistance, input pull-up resistor and output pull-up resistor；MBUS The anode circuit of bus connects positive pole signal by inputting pull-up resistor, and first is connected simultaneously also by the first current-limiting resistance The control terminal of switching tube, the cathode circuit of movable end one end connection MBUS buses of first switch pipe, is also connected by pull down resistor Ground signalling；The movable end other end of first switch pipe is the output terminal of bus voltage detection circuit, simultaneously also by output Pull-up resistor connects positive pole signal.

5. MBUS bus short circuits detection circuit according to claim 4, it is characterised in that the bus state judges electricity Road includes second switch pipe, the second current-limiting resistance and the second output pull-up resistor；The driving letter of bus voltage detection circuit output Number by the second current-limiting resistance connect second switch pipe control terminal；Movable end one end connection MBUS buses of second switch pipe Cathode traces, the movable end other end of second switch pipe is bus state decision circuitry, is also connected by the second output pull-up resistor Connect positive pole signal.

6. MBUS bus short circuits detection circuit according to claim 5, it is characterised in that the first switch pipe and Two switching tubes are triode or metal-oxide-semiconductor.