CN210225405U

CN210225405U - MBUS interface circuit of data transceiver

Info

Publication number: CN210225405U
Application number: CN201921396285.XU
Authority: CN
Inventors: Xiang Zhou; 周祥
Original assignee: Chongqing Source Of Green Environmental Technology Co Ltd
Current assignee: Chongqing Zhongyuan Lvlan Energy Technology Co ltd
Priority date: 2019-08-26
Filing date: 2019-08-26
Publication date: 2020-03-31
Anticipated expiration: 2029-08-26

Abstract

The utility model discloses a data transceiver MBUS interface circuit, MBUS interface circuit imbed in data transceiver, MBUS interface circuit is including the power supply circuit who is used for giving the power supply of MBUS interface circuit to and transmitting circuit and receiving circuit, power supply circuit and transmitting circuit are connected, transmitting circuit and receiving circuit are connected. The intelligent building signal transmission device is beneficial to the remote transmission of signals and has a very positive effect on the development of building intelligent engineering.

Description

MBUS interface circuit of data transceiver

Technical Field

The utility model belongs to data transceiver field, concretely relates to data transceiver MBUS interface circuit.

Background

The intelligent building control system belongs to distributed serial communication structure, and adopts data transceiver or bus controller to realize the connection between PC and serial communication bus, and completes the data organization, data conversion and data transmission via the data transceiver, so as to optimize the data structure of software platform and simplify the programming of the software platform. The data transceiver adopts an RS485 interface to connect with a field bus, is integrated with an MBUS protocol gateway, but cannot adapt to the requirements of multi-node (thousands), long distance (thousands of meters) and any wiring due to the self characteristics of the RS485 bus, and limits the application range and function expansion of the building control platform. The MBUS is a low-cost serial communication bus, has the two-way communication functions of large capacity (up to 200 points) of communication equipment, simple and convenient wiring (common twisted pair, no polarity and arbitrary branching), no need of additionally arranging a power supply for a slave station (direct extraction on the communication bus and power supply for a master station), node interruption alarm and the like. Therefore, compared with an RS485 bus, the MBUS system has low cost and strong anti-interference capability, and is widely applied to three-meter centralized reading, an intelligent home control network, a community intelligent control network, a central air-conditioning control system and the like.

In order to connect a plurality of building intelligent instruments and meters into a building control platform and better exert the efficiency of the building control platform so as to better serve building intelligent engineering, an MBUS communication interface must be expanded for the existing data transceiver.

SUMMERY OF THE UTILITY MODEL

To the defect among the prior art, the utility model provides a data transceiver MBUS interface circuit is favorable to the remote conveying of signal, has very positive effect to the development of building intelligent engineering.

Therefore, the utility model discloses a data transceiver MBUS interface circuit, MBUS interface circuit imbed in data transceiver, MBUS interface circuit is including being used for the power supply circuit for MBUS interface circuit power supply to and transmitting circuit and receiving circuit, power supply circuit and transmitting circuit are connected, transmitting circuit and receiving circuit are connected.

Further, the power supply circuit comprises a DC-DC conversion module and a power supply voltage stabilizing module which are connected in parallel.

Further, the sending circuit comprises a proportion following module and a current spreading control module which are connected in parallel.

Further, the receiving circuit comprises a bistable trigger, and the bistable trigger is used for extracting the voltage waveform and generating a signal meeting the TTL level requirement.

Furthermore, the interface circuit further comprises a signal isolation module, a short-circuit protection module and an overload alarm module, wherein the short-circuit protection module and the overload alarm module are embedded together to form a short-circuit overload protection circuit, and the number of the signal isolation modules is two and the two signal isolation modules are respectively arranged at a sending end and a receiving end of the internal communication interface of the data transceiver.

Furthermore, the signal isolation module comprises a photoelectric coupler, and the photoelectric coupler is respectively arranged at the transmitting end and the receiving end of the internal communication interface of the data transceiver and used for realizing the electrical isolation between the inside of the data transceiver and the instrument bus.

The utility model has the advantages that: the load capacity of the MBUS bus can be improved, the requirement on response parameters is reduced, the selection range of the device is wider, the device can work at a higher baud rate, and the long-distance transmission of signals is facilitated.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the technical solutions in the prior art will be briefly described below. In the drawings, like elements or portions are generally identified by like reference numerals. In the drawings, elements or portions are not necessarily drawn to scale.

Fig. 1 is a schematic circuit diagram of the power supply circuit of the present invention.

Fig. 2 is a schematic circuit diagram of the transmission circuit of the present invention.

Fig. 3 is a schematic circuit diagram of the receiving circuit of the present invention.

Fig. 4 is a schematic circuit diagram of the short circuit overload protection circuit of the present invention.

Detailed Description

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The following examples are only for illustrating the technical solutions of the present invention more clearly, and therefore are only examples, and the protection scope of the present invention is not limited thereby.

It is to be noted that unless otherwise specified, technical or scientific terms used herein shall have the ordinary meaning as understood by those skilled in the art to which the present invention belongs.

The MBUS interface circuit comprises a power supply circuit used for supplying power to the MBUS interface circuit, a sending circuit and a receiving circuit, wherein the power supply circuit is connected with the sending circuit, and the sending circuit is connected with the receiving circuit.

The power supply circuit comprises a DC-DC conversion module and a power supply voltage stabilizing module which are connected in parallel. The transmitting circuit comprises a proportion following module and a current expansion control module which are connected in parallel. The receiving circuit comprises a bistable trigger, and the bistable trigger is used for extracting a voltage waveform and generating a signal which meets the TTL level requirement. The interface circuit further comprises a signal isolation module, a short-circuit protection module and an overload alarm module, wherein the short-circuit protection module and the overload alarm module are embedded together to form a short-circuit overload protection circuit, and the number of the signal isolation modules is two and the two signal isolation modules are respectively arranged at a sending end and a receiving end of the internal communication interface of the data transceiver. The signal isolation module comprises a photoelectric coupler, and the photoelectric coupler realizes the electrical isolation between the inside of the data transceiver and the instrument bus.

In the MBUS interface circuit, two functions of bus voltage modulation and slave station equipment power supply are realized by different links, the static load current of the bus is provided by a current expansion control module, and a high-power triode is selected to provide a larger load current, so that the load capacity of the MBUS bus can be increased, and the number of slave station nodes can be up to 255.

In this embodiment, the MBUS system is a master-slave communication mode, at most one node on the bus transmits data in the same time period, and the bus is normally in an idle state, so that the driving capability of the MBUS interface circuit is enhanced except for completing level conversion. The master station transmits signal waveforms to the slave station through the MBUS bus in a voltage mode, the voltage range of the MBUS bus is 21-42V, the level of the bus 1 is higher than the level of the bus 0 by more than 10V, therefore, in the embodiment, the voltage of the master station transmitting the level 1 is defined to be 42V, the voltage of the master station transmitting the level 0 is defined to be 30V, and the bus keeps the state 1 in idle. Each slave draws a constant current, approximately 1.5m, from the MBUS bus as a power source for the slave meter, transmits a signal waveform to the master in a manner of drawing a current increment, "0" from the slave, the bus current increment being 10-20mA, and "1" from the slave, the bus current increment being 0 mA.

As shown in FIG. 1, FIG. 1 is a power supply circuit of this embodiment, the MBUS interface circuit has DC15V 1.5.5A power supply + U1 for supplying power, the power supply part generates-30V voltage by DC-DC conversion module IC1 as BUS negative electrode (-BUS), and generates +5V power by regulated power supply module IC2 to meet TTL level connection requirement of the controller.

As shown in fig. 2, fig. 2 is the transmitting circuit of the present embodiment, the T1 and the IC3 constitute a proportional follower module, and the ratio of R4 to R5 is properly selected, so that the output of the IC3 is controlled to be 0V ((TXD) ̅ = "1") and 12V ((TXD) ̅ = "0"), and the corresponding BUS voltage (+ between BUS and BUS) is 30V and 42V.

The IC4 and the T2 form a current spreading control module, and the aim of the current spreading control module is to inject current into a BUS (+ BUS) from T2, so that the voltage difference between two ends of the R7 is ensured to be 0V under a static state, namely the static load current of the BUS is completely provided by T2.

As shown in fig. 3, fig. 3 is a receiving circuit of this embodiment, the MBUS system is in a master-slave communication mode, and the slave station transmits a dynamic current waveform to the bus after receiving the master station handshake, and the master station is in an idle waiting state (the output of the IC3 remains in a "1" state).

When a certain slave station sends data, a current increment wave pattern of 10 mA-20 mA is led out from a bus, so that a dynamic voltage wave pattern is formed at two ends of a resistor R7+ R8, and the voltage wave pattern can be extracted by adopting a bistable trigger consisting of an IC5 to generate an (RXD) ̅ signal meeting the TTL level requirement.

Short-circuit protection circuit and overload alarm circuit as shown in fig. 4, the output side resistor R8 of the sending circuit plays a role in collecting bus overload alarm signals and protecting short circuit.

When the bus is overloaded and the voltage drop across the R8 is larger than a certain value, the TCb1 outputs low level, and the LED tube of the light-emitting diode lights an alarm.

When the + BUS and the-BUS are in short circuit, the maximum output current is 42/R8 (A), and the short-circuit current can be limited within a controllable value by selecting a proper R8 resistance value.

In addition, photoelectric couplers are respectively arranged at the transmitting end and the receiving end of the internal communication interface of the data transceiver, so that the internal circuit of the data transceiver is electrically isolated from the instrument bus, and the damage of the electromagnetic interference of the MBUS bus to the data transceiver is prevented.

In the above solution, the current-spreading transistor T2 only provides a static large current, and does not need too high dynamic response parameters, so that the selection of the device is easier, and the cost can be reduced.

Moreover, the bus voltage modulation is generated by the proportional following module IC3, the operational amplifier works in a low-current switching state, the output waveform distortion is small, and the MBUS bus can work at a higher baud rate.

The static voltage difference at the two ends of the R7 is 0V, and the incremental voltage difference formed by the slave station incremental current on the resistors R7 and R8 is large, so that the long-distance transmission of signals can be promoted.

In addition, only need to dispose according to the communication protocol based on Modbus that imbeds in the data transceiver, advance data template with the communication protocol configuration of intelligent instrument on the Modbus bus, can utilize the data transceiver to carry out data extraction, data organization, data transformation and data transfer to this intelligent instrument's relevant parameter.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the scope of the embodiments of the present invention, and are intended to be covered by the claims and the specification.

Claims

1. A data transceiver MBUS interface circuit is characterized in that the MBUS interface circuit is embedded in a data transceiver and comprises a power supply circuit used for supplying power to the MBUS interface circuit, a transmitting circuit and a receiving circuit, wherein the power supply circuit is connected with the transmitting circuit, and the transmitting circuit is connected with the receiving circuit.

2. The MBUS interface circuit of claim 1, wherein the power circuit comprises a DC-DC conversion module and a power regulator module connected in parallel.

3. The MBUS interface circuit of claim 1, wherein the transmitting circuit comprises a proportional follower module and a spreading control module connected in parallel.

4. The MBUS interface circuit of claim 1, wherein the receiving circuit comprises flip-flops for extracting a voltage waveform and generating a signal that meets TTL level requirements

A signal.

5. The MBUS interface circuit of a data transceiver according to any one of claims 1-4, wherein the interface circuit further comprises two signal isolation modules, a short-circuit protection module and an overload alarm module, the short-circuit protection module and the overload alarm module are embedded together to form a short-circuit overload protection circuit, and the signal isolation modules are respectively arranged at the transmitting end and the receiving end of the internal communication interface of the data transceiver.

6. The MBUS interface circuit of the data transceiver of claim 5, wherein the signal isolation module comprises a photoelectric coupler, and the photoelectric coupler is respectively arranged at the transmitting end and the receiving end of the internal communication interface of the data transceiver to realize the electrical isolation between the inside of the data transceiver and the instrument bus.