CN101976828B - M-BUS (Meter-Bus) intrinsic safety barrier - Google Patents
M-BUS (Meter-Bus) intrinsic safety barrier Download PDFInfo
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Abstract
The invention discloses an M-BUS (Meter-Bus) intrinsic safety barrier which is connected between a master station and a slave station of an M-BUS system and comprises an input stage, a protection stage I, a protection stage II and an output stage, wherein the input stage is used for realizing the polarity inversion of M-BUS input and limiting short circuit current of the M-BUS; the protection stage I and the protection stage II respectively comprise a voltage limiting circuit and an overcurrent protection circuit to form the redundancy protection of the intrinsic safety barrier; and the output stage is used for realizing the expansion from one channel to a plurality of channels and increasing the number of driving slave stations. The invention realizes multi-stage voltage limitation and overcurrent protection, conforms to the intrinsic safety requirement of the M-BUS, can expand the capacity of the M-BUS system and reduces device cost.
Description
Technical field
The invention belongs to technical field of electronic equipment, be specifically related to the guard grating between a kind of non-intrinsic safety equipment and the intrinsic safety equipment, it meets the M-BUS bus standard, and the M-BUS slave station that is operated in inflammable and explosive hazardous area can be connected to the M-BUS main website by the safety grid, forms the Sefe antiexplosion system.
Background technology
M-BUS(Meter-BUS, EN1434-3) be consumer instrument current international practice standard.It is a kind of economical and practical fieldbus, has good opening, its topological structure is bus structures, adopt common two core cable to connect, finish simultaneously the function of Power supply and data communication, when connecting, need not distinguish polarity, can be according to randomly topologically structured cable wiring manufacture, its construction cost and difficulty descend greatly.
M-BUS bus electric interfaces should meet the following requirements:
When slave station was powered by main website, each slave station obtained to be not more than the electric current of 2mA, and the main website driving force should be not less than 64 slave stations.
Main website to the communication of slave station is to realize by the mode that level changes.During mark (logic level is " 1 "): the bus voltage of bus voltage during than spacing is greater than 10V, and bus voltage is less than or equal to 42V; During spacing (logic level is " 0 "): bus voltage should be greater than 12V.
Slave station to master information transmission is that the variation by the slave station size of current realizes.During mark (logic level " 1 "): marking current is 0mA～1.5mA; During spacing (logic level " 0 "): spacing current is to increase approximately 11mA～20mA on the basis of marking current value; When bus was idle, master and slave station should keep mark condition.
Guard grating claims again safe retainer, to be connected between the intrinsically safe circuit in the immaterial safety circuit of place of safety and hazardous area, can be between place of safety and hazardous area the two-way transmission signal of telecommunication, and can limit place of safety that barrier for some reason causes to the energy transmission in hazardous area, will supply with voltage or the device of current limit in certain safe range of intrinsically safe circuit.
The essential safe type guard grating is applied in the design of intrinsic safe explosion-proof system, it is to be installed on harbor and to contain intrinsically safe circuit and the device of non-intrinsically safe circuit, limited the energy that is sent to on-the-spot intrinsic safety loop by current limliting and pressure limiting circuit in the circuit, thereby the dangerous energy that prevents non-intrinsically safe circuit seals in intrinsically safe circuit, it is called associate device in the intrinsic safe explosion-proof system, be the important component part of the essence safety system.The Generally Recognized as safe grid have Zener type, isolated.
The Zener type guard grating adopts fast acting fuse, current-limiting resistance or pressure limiting diode to limit with the electric flux to input in the circuit, thereby guarantees to output to the energy in hazardous area.
Isolating safety grid has adopted the circuit structure with input, output and the mutual electrical isolation of power supply three party, meets simultaneously the requirement of essential safety restriction energy.
In the M-BUS bus system, main website is that non-intrinsic safety equipment is positioned at the place of safety, and slave station is that intrinsic safety equipment is positioned at the hazardous area, needs to arrange between the master station and follow station guard grating that meets the intrinsic safety requirement, it will meet the M-BUS bus standard, can not affect master-salve station work and between communication.
Existing guard grating is applied on the M-BUS bus, has the following disadvantages:
1, Zener type guard grating, larger current-limiting resistance, excessive voltage drop causes bus-powered deficiency, reduces the ability that drives slave station; Internal circuit does not meet the M-BUS bus standard, and master-salve station cisco unity malfunction or master-salve station can not be communicated by letter; When fault, need to change fuse or guard grating, operate extremely inconvenient, the increase maintenance cost.
2, isolating safety grid, the output power supply capacity is relatively poor to cause driving that slave station quantity reduces or communication distance reduces; Do not meet the M-BUS bus standard, when being applied on the M-BUS bus, affect communicating by letter between main website and the slave station.
Summary of the invention
An object of the present invention is to remedy the deficiencies in the prior art; a kind of M-BUS bus intrinsic safety barriter, is provided; can carry out Multi-stage pressure limiting and overcurrent protection to the input of M-BUS bus, output meets the essential safety requirement, and it meets the M-BUS bus standard and can be used for the M-BUS bus.
Another object of the present invention is that M-BUS bus run quantity is expanded, and a main website can drive many M-BUS buses in turn, has expanded the capacity of M-BUS bus system, has reduced equipment cost.
The present invention is achieved through the following technical solutions:
A kind of M-BUS bus intrinsic safety barriter,, described bus intrinsic safety barriter, is connected between the master station and follow station of M-BUS bus system; It is characterized in that, described bus intrinsic safety barriter, comprises the following circuit that connects successively:
Input stage realizes the polarity conversion of M-BUS bus input, and the short circuit current of restriction M-BUS bus;
Protected level
, comprising pressure limiting circuit and current foldback circuit, its input connects the output of described input stage, this protected level
Output connect protected level
Input;
Protected level
, described protected level
With described protected level
Connect in turn described protected level
Also comprise a pressure limiting and current foldback circuit, with described protected level
Consist of together the redundancy protecting of M-BUS bus.
If the more than one passage of M-BUS bus requirements, then described M-BUS bus intrinsic safety barriter, also further comprises output stage, and the input of this output stage connects described protected level
Output, described output stage is a number of channels expanded circuit for combination electronic switch matrix or mechanical switch matrix, realizes the expansion from a passage to a plurality of passages, increases the quantity that drives slave station.Certainly, if only need a passage, shouldn't this level.
Input stage comprises the current-limiting resistance of a bridge-type change-over circuit and a low capacity.The bridge-type change-over circuit is realized the nonpolarity of M-BUS bus input, and current-limiting resistance is not so that during output short-circuit, very large short circuit current can occur.
Protected level
And protected level
Two identical circuit modules.It comprises a current sampling resistor, an electronic switch, a diode, a control chip and other components and parts, and the electrical characteristic of whole modular circuit meets the M-BUS standard.Control chip monitors output end voltage, when overpressure situation occurring, output voltage is adjusted in the voltage of setting by regulation electronic switch, also monitor simultaneously the pressure drop on the sampling resistor of input, when overcurrent condition occurring, the control electronic switch disconnects and being connected of exporting.No matter overvoltage or over current fault have occured, if fault continues always, the inner integrated fault timer of control chip can guarantee that all electronic switch fast and reliable ground turn-offs so, and the diode that is connected on output prevents the input of reverse voltage.
Output stage comprises signal isolation decoding circuit and switch matrix circuit.After the channel selecting signal of input carried out photoelectricity isolation, decoder circuit, can select a certain channel switch conducting, make it and protected level
Output connects, and reaches a passage M-BUS bus is expanded to multichannel purpose.Certainly, the quantity of extended channel can increase or reduce as required.
The present invention adopts said structure, and its electrical characteristic meets the M-BUS standard, can directly be applied on the M-BUS bus, and two-stage protected level circuit forms function of redundancy protection, and when one-level broke down therein, another grade can be born defencive function.Every grade all has independently pressure limiting and overcurrent protection function.Can expand the M-BUS number of channels by output stage.
Beneficial effect of the present invention: effectively limit the energy of input, make intrinsically safe equipment can be applied to safely the hazardous area; Meet the M-BUS bus standard, can directly apply on the M-BUS bus; Input and output pressure drop are little; Without fragile elements such as fuses, safeguard and substantially need not change; One passage M-BUS bus can be expanded to multichannel, reduce cost; Also can be used as the Generally Recognized as safe grid uses.
Description of drawings
Fig. 1 is general principles schematic diagram of the present invention;
Fig. 2 is the circuit theory schematic diagram of input stage among the present invention;
Fig. 3 is protected level among the present invention
, the protected level II the circuit theory schematic diagram;
Fig. 4 is the isolation decoding circuit principle schematic of output stage among the present invention;
Fig. 5 is the switch matrix principle schematic of output stage among the present invention;
Fig. 6 A is switch matrix the 1st channel switching circuit execution mode one principle schematic of output stage among the present invention;
Fig. 6 B is switch matrix the 1st channel switching circuit execution mode two principle schematic of output stage among the present invention.
Embodiment
The present invention is further illustrated below in conjunction with instantiation and accompanying drawing
M-BUS bus standard regulation: the M-BUS bus is non-polar, main website be by the variation of control bus voltage (when sending logical one, output HIGH voltage; When sending logical zero, output LOW voltage) send data to slave station, the scope of voltage transformation is greater than 10V.Slave station is (when sending logical one, to keep bus current constant by the variation of control bus electric current; When sending logical zero, make bus current increase a fixed value) send data, the scope 11mA of curent change～20mA to main website.
As shown in Figure 1, M-BUS bus intrinsic safety barriter, comprises the following circuit that connects successively:
Input stage has the circuit of inputting polarity conversion and current-limiting resistance;
Protected level
, have the circuit of pressure limiting and overcurrent protection function;
Protected level
, have the circuit of pressure limiting and overcurrent protection function;
Output stage, combination electronic switch matrix or mechanical switch matrix are number of channels expanded circuits, realize the expansion from a passage to a plurality of passages, increase the quantity that drives slave station, if only need a passage, this grade circuit shouldn't.
By reference to the accompanying drawings, the particular circuit configurations of circuit modules at different levels is analyzed as follows:
As shown in Figure 2, input stage one end connects the input of M-BUS bus, and the positive and negative electrode of the other end is connected respectively to protected level
Positive and negative electrode.It comprises the current-limiting resistance of a bridge-type change-over circuit and a low capacity, and the M-BUS bus is after bridge type change-over circuit D1 realizes reversal, and positive pole is connected to protected level through a current-limiting resistance R1
Positive pole, negative pole is directly connected to protected level
Negative pole.Input stage has realized the nonpolarity input of M-BUS bus, the maximum short circuit current when having limited output short-circuit.
Protected level
And protected level
Be identical circuit structure, as shown in Figure 3, in the present embodiment, the operating voltage scope of design of protected level is 9V to 42V, and the pressure limiting point is designed to 36V, crosses flow point and is designed to 0.2A.
As shown in Figure 3, with protected level
For example illustrates its circuit structure: protected level
Comprise a current sampling resistor R3, an electronic switch (MOSFET manages Q1), diode D2, a control chip U1 and other components and parts.The positive pole of input successively series current sampling resistor R3, MOSFET is managed Q1, diode D2 to output, the pin 7 of control chip U1 and pin 8 are connected respectively to the two ends of current sampling resistor R3, the pin 5 of control chip U1 is by resistance R 4 driven MOS FET pipe Q1, the conducting of control inputs and output or shutoff, be connected to the both positive and negative polarity of the output behind the MOSFET pipe Q1 after voltage sample resistance R 5 and the R6 series connection, centre tap is connected to the pin 2 of control chip U1, and resistance R 2 and C1 are the control chip U1 necessary components and parts of working.
Its operation principle is: the pin of control chip U1 2 monitors the feedback voltage of voltage sample resistance R 5 and R6, and when input voltage during greater than 36V, its pin 5 output control signals are regulated MOSFET pipe Q1 output is adjusted to 36V; The pressure drop at control chip U1 pin 7 and pin 8 standby current sampling resistor R3 two ends, when through the electric current of R3 during greater than 0.2A, the pressure drop at current sampling resistor R3 two ends surpasses set point, and its pin 5 output control signals disconnect and being connected of exporting MOSFET pipe Q1; Diode D2 prevents the input of reverse voltage.
In the present embodiment, control chip U2 selects LT4356-3.
Protected level
The positive pole of output and protected level
The positive pole of input connects, protected level
The negative pole of output and protected level
The negative pole of input connects, and two-stage protected level circuit forms function of redundancy protection, and when one-level broke down therein, another grade can be born defencive function.
Output stage comprises signal isolation decoding circuit and switch matrix circuit.In the present embodiment, output stage expands to 16 passages, and 4 the tunnel select signal to select corresponding passage by the 4-16 decoder.
As shown in Figure 4,4 paths selection signal after the reversal of bridge type change-over circuit, drives the light lotus root by a resistance respectively, and the signal after the isolation of light lotus root is input to the input of chip U5,16 road signal driver switch matrix circuits after decoding output.
As shown in Figure 5, be the switch matrix circuit principle schematic, comprise 16 identical channel switchs, the input of each channel switch and protected level
Output connect, output is connected to lead-out terminal, control end with isolate the decoding circuit output and be connected.By channel switch, control signal can be controlled protected level simultaneously
Conducting or the shutoff of output head anode, negative pole and lead-out terminal.Channel switch is a double-pole switch.
In the present embodiment, as an example of the 1st channel switch of switch matrix circuit example its circuit structure principle is described.
As shown in Figure 6A, be the 1st channel switching circuit execution mode one principle schematic of switch matrix circuit.This circuit is comprised of 4 electronic switches: the 1st electronic switch that is comprised of resistance R A1, RA4 and triode QA2, manage the 2nd electronic switch that QA1 forms by resistance R A2, RA3 and MOSFET, by diode DA1, the 3rd electronic switch that resistance R A5 and triode QA3 form is managed the 4th electronic switch that QA4 forms by resistance R A6, RA7 and MOSFET; Wherein the end of resistance R A4 is connected to the base stage of triode QA2, and the other end is connected to the passage output signal of signal isolation decoding circuit; The source class of MOSFET pipe QA1 is connected to protected level
The negative pole of output drains as the negative pole output of this passage, is connected to lead-out terminal; The source class of MOSFET pipe QA4 is connected to protected level
The positive pole of output drains as the positive pole output of this passage, is connected to lead-out terminal.
Operation principle is: input control signal is controlled the 1st electronic switch conducting or shutoff; the 1st electronic switch is controlled the 2nd electronic switch and the 3rd electronic switch conducting or shutoff; the 3rd electronic switch is controlled the 4th electronic switch conducting or shutoff, and namely input control signal is controlled protected level simultaneously
Conducting or the shutoff of output head anode, negative pole and lead-out terminal.
Shown in Fig. 6 B, be the 1st channel switching circuit execution mode two principle schematic of switch matrix circuit.The electronic switch that is comprised of resistance R A8, RA9 and triode QA5 drives relay K A1, and the diode DA2 in parallel with relay K A1 plays afterflow effect, protected level
The positive pole of output and the common port that negative pole is connected respectively to relay K A1, the Chang Kaiduan of relay K A1 is connected respectively to the lead-out terminal of this passage.Input control signal drives the Control protected level by electronic switch
Conducting or the shutoff of output head anode, negative pole and lead-out terminal.
The present patent application people has done detailed explanation and description in conjunction with Figure of description to embodiments of the invention; but those skilled in the art should understand that; above embodiment only is the preferred embodiments of the invention; detailed explanation is just in order to help the reader to understand better spirit of the present invention; and be not limiting the scope of the invention; on the contrary, any any improvement or modification of doing based on invention spirit of the present invention all should drop within protection scope of the present invention.
Claims (3)
1. M-BUS bus intrinsic safety barriter,, described bus intrinsic safety barriter, is connected between the master station and follow station of M-BUS bus system; It is characterized in that, described bus intrinsic safety barriter, comprises the following circuit that connects successively:
Input stage realizes the polarity conversion of M-BUS bus input, and the short circuit current of restriction M-BUS bus;
Protected level I comprises pressure limiting and current foldback circuit, and its input connects the output of described input stage, and the output of this protected level I connects the input of protected level II;
Protected level II, described protected level II is connected in turn with described protected level I, and described protected level II also comprises a pressure limiting and current foldback circuit, consists of the redundancy protecting of M-BUS bus with described protected level I;
Described input stage comprises the current-limiting resistance of a bridge-type change-over circuit and a low capacity, and the input of described bridge-type change-over circuit connects the input of M-BUS bus, and output connects described protected level I input anode by the current-limiting resistance of low capacity;
Described M-BUS bus intrinsic safety barriter, also further comprises output stage, and the input of this output stage connects the output of described protected level II, realizes the expansion from a passage to a plurality of passages, increases the quantity that drives slave station; Described output stage comprises signal isolation decoding circuit and the switch matrix circuit that is linked in sequence, and described switch matrix circuit is combination electronic switch matrix or mechanical switch matrix; The signal isolation decoding circuit of described output stage drives optocoupler by a resistance, channel selecting signal after the bridge-type change-over circuit reversal of input stage is carried out light-coupled isolation, signal after the light-coupled isolation is input to the input of chip U5, output signal after decoding, the driving switch matrix circuit; The input of each channel switch of described switch matrix circuit is connected with the output of protected level II, output is connected to lead-out terminal, control end is connected with isolation decoding circuit output, by channel switch, control signal is controlled conducting or the shutoff of output head anode, negative pole and the lead-out terminal of protected level II simultaneously;
Described protected level I comprises a current sampling resistor, an electronic switch, a diode, a control chip, the positive pole of this protected level I input is series current sampling resistor, electronic switch and diode successively, input to described control chip by the current sampling signal of current sampling resistor and the output end voltage sampled signal of described output stage, this control chip links to each other with the control end of described electronic switch;
The inner integrated fault timer of described control chip; when over-voltage condition appears in the output end voltage of protected level I; output is adjusted in the voltage of setting by regulation electronic switch; when overcurrent situations appearred in the input of this protected level I, control electronic switch disconnection input was connected with output.
2. M-BUS bus intrinsic safety barriter, according to claim 1 is characterized in that, described electronic switch is MOSFET pipe (Q1), and described electronic switch controling end is the grid of described MOSFET pipe (Q1).
3. M-BUS bus intrinsic safety barriter, according to claim 1 is characterized in that, described protected level II preferably has the circuit structure identical with described protected level I.
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| CN 201010541844 CN101976828B (en) | 2010-11-12 | 2010-11-12 | M-BUS (Meter-Bus) intrinsic safety barrier |
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Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102185805B (en) * | 2011-05-17 | 2013-11-13 | 惠州市奥罗拉科技有限公司 | M-BUS (Meter-Bus) driving circuit |
| CN102496904B (en) * | 2011-12-20 | 2017-06-16 | 深圳市骏普科技开发有限公司 | A kind of Self-powered communication-bus short-circuit protection method |
| CN104682336A (en) * | 2013-12-03 | 2015-06-03 | 深圳市海洋王照明工程有限公司 | Intrinsic safety circuit |
| CN109066628A (en) * | 2018-09-05 | 2018-12-21 | 南京志卓电子科技有限公司 | It is a kind of according to instruction hardware realization multi-level output current-limiting circuit |
| CN109360404B (en) * | 2018-12-13 | 2023-08-15 | 湖南常德牌水表制造有限公司 | Multichannel intelligent meter reading remote transmission device and method for M-Bus master station |
| CN109754591A (en) * | 2018-12-21 | 2019-05-14 | 湖南常德牌水表制造有限公司 | A kind of kilowatt meter reading-out system and meter register method |
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Denomination of invention: Intrinsic safety barrier of M-BUS bus Effective date of registration: 20201104 Granted publication date: 20130327 Pledgee: CHONGQING QIANWEI SCIENCE & TECHNOLOGY GROUP Co.,Ltd. Pledgor: CHONGQING INTELLIGENCE WATER Co.,Ltd. Registration number: Y2020500000015 |
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