Bridge circuit device and its bus circuit based on RS485Technical field
It the utility model is related to bus circuit technology, more particularly to bridge circuit device and its bus circuit based on RS485.
Background technology
RS485 is two-wire system, half-duplex, differential signal communication interface (physical layer).Referring to Fig. 1, traditional RS485 busesMultiple equipment is allowed to be connected in same bus, these equipment communicate usually using ModBus protocol formats, and each equipment is pre-One 485ID is first set.Main frame, with the equipment interaction in bus, each equipment is distinguished by 485ID by the way of poll.It is mainAll devices can receive when machine sends request, but that equipment response that only 485ID matches, 485 buses are half pairWork, the same time can only have a data sender.The all the sensors of traditional RS485 buses are connected in a data lines,Line is longer, and signal attenuation is more serious, and communication is easier by outside electromagnetic interference.
Therefore, exist in the prior art to can in RS485 buses using and can overcome signal attenuation it is serious,Communication is easily needed by the RS485 circuit arrangements of outside electromagnetic interference.
Utility model content
The purpose of this utility model is to provide a kind of bridge circuit device available in RS485 buses and based on bridge electricityThe bus circuit of road device, it can freely increase as needed in bus or reduce bridge circuit device without to bus electricityRoad carries out complex configurations, at the same can overcome signal attenuation is serious, communication easily by outside electromagnetic interference the defects of.
According to one side of the present utility model, there is provided a kind of bridge circuit device based on RS485, including processor,For connected by bus the first RS485 serial ports of a upper bridge circuit device with for connecting next bridge circuit by bus2nd RS485 serial ports of device, it is characterised in that further comprise：
As the 3rd serial ports at the L ends of bridge circuit device, for providing polytype interface so that connection type matchesSensor；
Wherein, P end of the first RS485 serial ports as bridge circuit device, filled for connecting a upper bridge circuit by busPut；N-terminal of the 2nd RS485 serial ports as bridge circuit device, for connecting next bridge circuit device by bus；
The processor and the first RS485 serial ports, the 2nd RS485 serial ports and the 3rd serial ports carry out signal interaction.
Wherein, the 3rd serial ports is the set serial ports of RS485, RS422 and RS232 serial ports, and RS485 is based on for connectingThe sensor of work, the sensor based on RS422 work and the sensor based on RS232 work.
Wherein, the bridge circuit device further comprises：Serial ports is aided in, for connecting the sensor of desired type.
Wherein, the processor is C51 chips, and the first RS485 serial ports and the 2nd RS485 serial ports are RJ45 interfaces.
Wherein, the first RS485 serial ports, the 2nd RS485 serial ports and the 3rd serial ports be it is independent of each other, can be independently of one anotherEnter row data communication simultaneously.
Wherein, bridge circuit device also includes the dry node port positioned at L ends, for connecting dry node.
According to other side of the present utility model, there is provided a kind of bus circuit based on RS485, including m series connectionThe node and main frame being connected in RS485 buses, m are positive integer, it is characterised in that：
Each node is the bridge circuit device such as one of claim 1-4；
The P ends of first node are connected with the main frame, and the L ends of m-th of node are hanging, and the P ends of i-th of node are connected toThe L ends of the i-th -1 node, i 2,3,4 ..., m-1；
Data wire between -1 node of k-th of node and kth is independent data line segment, k 2,3,4 ..., m.
Wherein, each port in the P ends of node, L ends and N-terminal is configured with 4 lines, wherein 2 lines are signal wire, separatelyOuter one, 2 lines are ground wire, and one is 5V power lines.
Wherein, the main frame carries out data interaction by bridge circuit device and sensor.
Wherein, data interaction is carried out by bridge circuit device and sensor in main frame, the bridge circuit device can also be withThereafter bridge circuit device communication.
According to the utility model, the L ends of the bridge circuit device based on RS485 can support polytype sensor, thisThe agreement of a little sensors can be arbitrary.The bridge circuit device based on RS485 in bus is that data porter i.e. data turnSend out equipment.Bridge circuit device is bridge of the main frame with sensor communication, and it provides a difference and tradition for main frame and sensorThe communication line of RS485 buses.The bridge circuit device based on RS485 is only connected in RS485 buses, unlike traditional RS485 busesIt is directly connected to sensor like that.During using RS485 buses, main frame no longer directly interacts with sensor, but is assisted using RS485 bridgesView interacts with bridge circuit device.Bridge agreement provides order and " sensors command " after packing is transmitted into sensor in fact for main frameInteraction of the existing main frame with sensor.
Brief description of the drawings
By that will become and the specific embodiment part provided, feature and advantage of the present utility model referring to the drawingsIt is easier to understand, in the accompanying drawings：
Fig. 1 is the conventional bus circuit diagram of the prior art based on RS485；
Fig. 2 is the port composition schematic diagram according to the bridge circuit device based on RS485 of the utility model embodiment.
Fig. 3 is the composition schematic diagram according to the bridge circuit device based on RS485 of the utility model embodiment.
Fig. 4 is the bus circuit schematic diagram according to the bridge circuit device based on RS485 of the utility model embodiment.
Embodiment
Illustrative embodiments of the present utility model are described in detail with reference to the accompanying drawings.To illustrative embodimentsDescription merely for the sake of demonstration purpose, and be definitely not to the utility model and its application or the limitation of usage.
In the utility model, the bridge circuit device based on RS485 has three ports, respectively L ends, P ends and N-terminal, P endsIt is respectively used to connect upper one and next bridge circuit device with N-terminal, L ends are used to be connected to sensor.Bridge electricity based on RS485Road device is directly connected in RS485 buses.So, sensor is no longer directly connected in RS485 buses, and main frame is no longer directInteract with sensor, but interacted using 485 bus protocols with bridge circuit device.Bridge circuit device and connected sensorA node being properly termed as in RS485 buses.It all it is one section independent between each two bridge circuit device in RS485 busesData wire, that section of line i.e. L ends for being based even on RS485 bridge circuit device connection sensor are also one section of independent data wire,Bridge circuit device based on RS485 transmits data among the nodes by way of relay.It can be seen that using the utility model, sectionData line length between point shortens, therefore signal attenuation is small, and also mutually strain is strong for the signal antijamming capability on signal wire.
In the utility model, the bridge circuit device based on RS485 in bus is data porter i.e. data transfer equipment,RS485 buses are also to use RS485 physical interfaces, but without using ModBus agreements, but use custom protocol.Self-defined associationView is not essential in the utility model, and the utility model can also use other agreements by those skilled in the art, thereforeThe introduction to custom protocol is omitted here.Bridge circuit device is bridge of the main frame with sensor communication, and it is main frame and sensingDevice provides the communication line of a difference and traditional RS485 buses.Only bridge circuit of the connection based on RS485 fills in RS485 busesPut, sensor is directly connected to unlike traditional RS485 buses.During using RS485 buses, main frame is no longer directly handed over sensorMutually, but RS485 bridges agreement is used to be interacted with bridge circuit device.Bridge agreement provides order and supplies main frame by the " sensor after packingInstruction " is transmitted to sensor to realize interaction of the main frame with sensor.
2-4 describes in detail to the utility model below in conjunction with the accompanying drawings.
Fig. 2 is the port composition schematic diagram according to the bridge circuit device based on RS485 of the utility model embodiment.Fig. 3Show the composition schematic diagram of the bridge circuit device based on RS485 according to the utility model embodiment.Bridge circuit device includesProcessor, the first RS485 serial ports and the 2nd RS485 serial ports.First RS485 serial ports is used to connect a upper bridge circuit by bus2nd RS485 serial ports of device, the 2nd RS485 serial ports are used for the first RS485 that next bridge circuit device is connected by busSerial ports.The bridge circuit device further comprises the 3rd serial ports at the L ends as bridge circuit device, polytype for providingThe sensor that interface matches for connection type.
In the utility model, P end of the first RS485 serial ports as bridge circuit device, for connecting upper one by busBridge circuit device；N-terminal of the 2nd RS485 serial ports as bridge circuit device, for connecting next bridge circuit device by bus.The processor and the first RS485 serial ports, the 2nd RS485 serial ports and the 3rd serial ports carry out signal interaction.
Wherein, the 3rd serial ports is the set serial ports of RS485, RS422 and RS232 serial ports, and RS485 is based on for connectingThe sensor of work, the sensor based on RS422 work and the sensor based on RS232 work.
It is preferred that the bridge circuit device further comprises aiding in serial ports, for connecting the sensor of desired type.
It is preferred that the processor is C51 chips, the first RS485 serial ports and the 2nd RS485 serial ports connect for RJ45Mouthful.
In the utility model, the first RS485 serial ports, the 2nd RS485 serial ports and the 3rd serial ports are independent of each other, can thatThis independently enters row data communication simultaneously.
It is preferred that bridge circuit device also includes the dry node port positioned at L ends, for connecting dry node.
In the utility model, although the interface based on RS485 is half duplex communication, the bridge circuit dress based on RS485It is independent to put three interfaces of inside, and they can carry out data communication simultaneously, that is to say, that bridge circuit device is by P endsWhen data forwarding is to N-terminal, the sensor that still can be connected with L ends is communicated.This working method is than half duplex communicationTraditional RS485 buses are more efficient.
Traditional RS485 buses can only connect the sensor of RS485 interfaces, and be typically only capable to be led to Modbus agreementsNews.And in the utility model, the L ends of the bridge circuit device based on RS485 can support polytype sensor, these sensingsThe agreement of device can be arbitrary.Alternatively, L ends can also be configured to only connect a type of sensor.In RS485 bridgesIn bus, between main frame and these dissimilar sensors communication will not produce it is any conflict because actual directly with sensorThe bridge circuit device of communication is only limitted to that RS485 bridge circuit device that it is connected.
Fig. 4 shows the bus circuit schematic diagram of the bridge circuit device based on RS485 according to the utility model embodiment.As shown in figure 4, the bus circuit based on RS485 includes the m nodes and main frame being connected in series in RS485 buses, m is just wholeNumber.Each node is foregoing bridge circuit device, and the P ends of first node are connected with the main frame, m-th of nodeL ends it is hanging, the P ends of i-th of node are connected to the L ends of the i-th -1 node, i 2,3,4 ..., m-1.K-th of node andData wire between k-1 node is independent data line segment, k 2,3,4 ..., m.
It is preferred that each port in the P ends of node, L ends and N-terminal is configured with 4 lines, wherein 2 lines are signal wire,Other one, 2 lines are ground wire, and one is 5V power lines.
It is preferred that the main frame carries out data interaction by bridge circuit device and sensor.
It is preferred that carry out data interaction by bridge circuit device and sensor in main frame, the bridge circuit device can be withCommunicated with bridge circuit device thereafter.
Referring to Fig. 4, in the bus circuit based on RS485, it between node is all one section of independence that each two bridge circuit device, which is,Data wire, that section of line for being based even on the i.e. L ends connection sensor of RS485 bridge circuit device is also one section of independent dataLine, bridge circuit device transmit data among the nodes by way of relay.Clearly as the data line length between node becomesIt is short, thus signal attenuation diminishes, antijamming capability also just becomes strong.
In the utility model, bridge circuit device and that sensor that it is connected are referred to as a node altogether.
Although the utility model is described with reference to illustrative embodiments, but it is to be understood that the utility modelThe embodiment be described in detail and shown in text is not limited to, in the feelings without departing from claims limited rangeUnder condition, those skilled in the art can make various changes to the illustrative embodiments.