CN111147146B

CN111147146B - Optical fiber network-based photoelectric transceiving system of industrial field bus

Info

Publication number: CN111147146B
Application number: CN202010006134.XA
Authority: CN
Inventors: 刘建中; 魏毅; 刘志哲; 冯经韬; 王轩
Original assignee: Hangzhou Hollysys Automation Co Ltd
Current assignee: Hangzhou Hollysys Automation Co Ltd
Priority date: 2020-01-03
Filing date: 2020-01-03
Publication date: 2021-03-23
Anticipated expiration: 2040-01-03
Also published as: CN111147146A

Abstract

The application discloses industry field bus's photoelectricity receiving and dispatching system based on optical network includes: a master device; a main photoelectric transceiver connected with the main device through a cable; a splitter connected to the main optical transceiver through an optical fiber; n slave photoelectric transceivers connected with the optical splitter through optical fibers; n is a positive integer not less than 2; and each slave device is connected with the master device in a communication way based on the slave photoelectric transceiver, the optical splitter and the master photoelectric transceiver connected with the slave device. By applying the scheme of the application, the number of optical fibers is reduced, the number of photoelectric transceivers is also reduced, and the cost is saved.

Description

Optical fiber network-based photoelectric transceiving system of industrial field bus

Technical Field

The invention relates to the technical field of industrial field communication, in particular to a photoelectric transceiving system of an industrial field bus based on an optical fiber network.

Background

With the continuous development of economy and technology, the scale of the factory is larger and larger, the equipment is more and more, the devices and the components are more and more dispersed, and the scale of the control equipment of the factory is more and more complex.

At present, field buses such as Profibus-DP, Modbus and CAN are generally adopted for information transmission among control devices, and when the distance is larger than 200m, the field buses need to be converted into optical fiber signals for long-distance transmission. However, the current transmission scheme can only realize point-to-point optical fiber signal transmission, and when there are many dispersed points in the industrial field, a large number of optical fibers are required for connection, and the number of optical fiber transmission devices is also increased greatly.

Referring to fig. 1, when the devices 1-4 need to communicate with the device 5, the device 5 needs to be configured with 4 sets of independent communication lines, for example, the device 5 is communicatively connected with the device 3 through the optoelectronic transceiver 5, and the device 5 is communicatively connected with the device 1 through the optoelectronic transceiver 6, and the optoelectronic transceiver 1. Even if a plurality of devices are close to each other, the transmission fiber needs to be independently laid, and if the device needs to be used redundantly, at least 2 single-mode fibers or 2 pairs of multi-mode fibers are needed.

Along with the device quantity of mill constantly increases, lead to adopting optic fibre to carry out information transmission and need use a large amount of long optic fibre to lay, on the one hand, can lead to the construction cost of mill to rise after the optic fibre quantity is great, on the other hand, the environment of industrial field is complicated, the emergence number of the optic fibre trouble condition can be increased in the optic fibre quantity increase, and behind the optic fibre trouble, need carry out the optical fiber fusion again and accomplish the restoration, the operation is comparatively complicated, it is also comparatively long consuming time, lead to optical fiber communication to have received very big restriction when transmitting industrial field bus signal, some mills directly give up the use even.

In summary, how to reduce the number of used optical fibers and save the cost is a technical problem that needs to be solved urgently by those skilled in the art.

Disclosure of Invention

The invention aims to provide an optical fiber network-based photoelectric transceiving system of an industrial field bus, so as to reduce the use number of optical fibers and save the cost.

In order to solve the technical problems, the invention provides the following technical scheme:

an optical-electrical transceiving system of an industrial field bus based on a fiber optic network, comprising:

a master device;

a main optoelectronic transceiver connected to the main device by a cable;

an optical splitter connected to the main optical transceiver through an optical fiber;

n slave photoelectric transceivers connected with the optical splitter through optical fibers; n is a positive integer not less than 2;

and each slave device is connected with the master device through a cable, and the slave photoelectric transceiver connected with the slave device, the optical splitter and the master photoelectric transceiver are used for realizing communication connection with the master device.

Preferably, for the master optical-electrical transceiver or any one of the slave optical-electrical transceivers, the process of converting the electrical signal into the optical signal by the optical-electrical transceiver includes: according to a preset coding rule, coding the low-frequency electric signal into a high-frequency signal and then transmitting the signal through an optical fiber interface;

correspondingly, for the master optical-electrical transceiver or any one of the slave optical-electrical transceivers, the process of converting the optical signal into the electrical signal by the optical-electrical transceiver includes: and decoding the high-frequency signal received from the optical fiber interface into a low-frequency electric signal according to a preset decoding rule, and then transmitting the signal.

Preferably, the preset encoding rule is:

adopting a rectangular wave with a first frequency as a basic frequency, adopting a second frequency as a counting clock, and lengthening the low level of the modulated high-frequency signal by k clock cycles at the falling edge of the electric signal; stretching the high level of the modulated high-frequency signal by k clock cycles at the rising edge of the electric signal; when the electrical signal does not jump, the modulated high-frequency signal is a rectangular wave with the frequency equal to the first frequency;

the second frequency is higher than the first frequency, the first frequency is higher than the frequency of the electric signal, and k is a preset positive integer.

Preferably, the preset decoding rule is:

when the low level duration time of the high-frequency signal received from the optical fiber interface exceeds p clock cycles and does not exceed k clock cycles, pulling down the level of the decoded low-frequency electric signal; when the high level duration of the high-frequency signal received from the optical fiber interface exceeds p clock cycles and does not exceed k clock cycles, pulling up the level of the decoded low-frequency electric signal; when the high level duration time of the high-frequency signal received from the optical fiber interface does not exceed p clock cycles and the low level duration time does not exceed p clock cycles, the level of the decoded low-frequency electric signal is kept unchanged; wherein k and p are positive integers and p is less than k.

Preferably, the master device is specifically configured to:

sending, by the master optoelectronic transceiver, the splitter and the N slave optoelectronic transceivers, inquiry data to the N slave devices, such that a target slave device of the N slave devices to which the inquiry data is directed, after receiving the inquiry data, sends feedback data to the master device through a slave optoelectronic transceiver connected to the target slave device, the splitter and the master optoelectronic transceiver.

Preferably, the receiving function and the transmitting function of the master photoelectric transceiver are both kept in an on state, and the receiving functions of the N slave photoelectric transceivers are both kept in an on state;

and for any one of the N slave optoelectronic transceivers, after the slave optoelectronic transceiver transmits the feedback data to the master device, the slave optoelectronic transceiver continues to transmit the rectangular wave of the first frequency until the slave optoelectronic transceiver receives interrogation data not intended for a slave device connected to the slave optoelectronic transceiver, the slave optoelectronic transceiver stops transmitting the rectangular wave of the first frequency.

Preferably, the first frequency is 24MHz, and the second frequency is 96 MHz.

Preferably, the method further comprises the following steps:

a class II main optoelectronic transceiver connected to the main device by a cable;

connecting a second type of slave photoelectric transceiver with the second type of master photoelectric transceiver through an optical fiber, and connecting the second type of slave photoelectric transceiver with M slave devices through cables, wherein each slave device in the M slave devices realizes communication connection with the master device based on the second type of slave photoelectric transceiver and the second type of master photoelectric transceiver; m is a positive integer not less than 2.

In the scheme of this application, main equipment 10 is connected with main photoelectric transceiver 20 through the cable, and optical splitter 30 is connected with main photoelectric transceiver 20 through optic fibre to optical splitter 30 is connected with N from photoelectric transceiver 40 through optic fibre, can see that, compare the point-to-point connected mode in traditional scheme, in the scheme of this application, this section distance of main photoelectric transceiver 20 to optical splitter 30 has reduced the quantity of optic fibre, just also is favorable to practicing thrift the cost. And also reduces the number of opto-electronic transceivers required for the solution.

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 description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a schematic structural diagram of a conventional optoelectronic transceiver system of an industrial fieldbus;

fig. 2 is a schematic structural diagram of an optical-electrical transceiver system of an industrial fieldbus based on an optical fiber network according to an embodiment of the present invention;

FIG. 3 is a diagram of an optoelectronic transceiver hardware architecture in accordance with one embodiment of the present invention;

FIG. 4 is a schematic diagram of encoded waveforms for Profibus-DP communication in an optoelectronic transceiver in accordance with an embodiment of the present invention;

FIG. 5 is a waveform diagram of an optoelectronic transceiver receiving an optical signal and decoding and outputting a Profibus-DP according to an embodiment of the present invention;

fig. 6 is a schematic structural diagram of an optical-electrical transceiver system of an industrial fieldbus based on an optical fiber network according to another embodiment of the present invention.

Detailed Description

The core of the invention is to provide an optical fiber network-based photoelectric transceiving system of the industrial field bus, which reduces the number of optical fibers and the number of photoelectric transceivers required by the scheme, and is beneficial to saving the cost.

In order that those skilled in the art will better understand the disclosure, the invention will be described in further detail with reference to the accompanying drawings and specific embodiments. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 2, fig. 2 is a schematic structural diagram of an optical-electrical transceiver system of an optical fiber network-based industrial fieldbus according to the present invention. The optical-electrical transceiving system of the industrial field bus based on the optical fiber network can comprise:

a master device 10;

a main photoelectric transceiver 20 connected to the main device 10 through a cable;

an optical splitter 30 connected to the main optical transceiver 20 through an optical fiber;

n slave opto-electronic transceivers 40 connected to the optical splitter 30 by optical fibers; n is a positive integer not less than 2;

n slave devices 50 connected to the N slave opto-electronic transceivers 40 by cables, respectively, and each slave device 50 makes a communication connection with the master device 10 based on the slave opto-electronic transceiver 40, the optical splitter 30, and the master opto-electronic transceiver 20 connected to the slave device 50.

Specifically, the optoelectronic transceiver is a device that can convert an electrical signal into an optical signal and also convert the optical signal into an electrical signal. For example, fig. 3 is a diagram of an optoelectronic transceiver hardware architecture in one embodiment. Of course, in other specific situations, an optoelectronic transceiver with other architecture may be adopted, and the functions of the present application may be implemented.

When the electric signals are transmitted in the cable, the communication protocol CAN adopt a bus protocol such as Profibus-DP, Modbus, CAN and the like. The application takes Profibus-DP as an example. The physical layer of the Profibus-DP signal is RS485, so the transceiver in fig. 3 can use an RS485 chip, and needs to control the communication direction for half-duplex operation. The fiber interface of fig. 3 may be implemented as a fiber optic transceiver that is compatible with the requirements of GPON, EPON networks, or other high power fiber optic transceivers.

In fig. 3, an electrical signal may be accessed through an IO-BUS prefabricated cable or a prefabricated connection terminal, and then enters a processor through a transceiver chip, and after processing and internal processing, the processor may forward a received Profibus-DP signal, output a single-ended LVTTL level signal, convert the signal into a differential LVPECL level signal after level conversion, and then drive an optical module to convert the signal into an optical signal, and transmit the optical signal to the outside through an optical fiber.

Similarly, the optical module in fig. 3 may convert the received optical signal into an LVPECL level signal, and the electrical signal enters the processor after being converted from the LVPECL to the LVTTL level. After being processed by the processor, the signals are externally forwarded to the IO-BUS prefabricated cable or a prefabricated ground wiring terminal through the transceiver chip by the processor.

In addition, a corresponding function switch may be further disposed inside the optoelectronic transceiver in fig. 3, for selecting functions such as communication rate, protocol format, or error data interception. And the optoelectronic transceiver of fig. 3 is also internally provided with a power supply diagnostic function. Reset refers to a power-on reset or a fault reset. The indicator light may be used to indicate the link communication status as well as the power status of the optoelectronic transceiver. The power supply of the main chip inside the optoelectronic transceiver is provided by a 24V to 5V power supply, and if other lower voltage is needed, for example, 3.3V, the power supply can be obtained by 5V step-down.

In the communication process, the communication rates of 187.5Kbps, 500Kbps, 1.5Mbps and 3Mbps are commonly used in Profibus-DP, and the communication rate is relatively low.

The splitter 30 is a passive device, also called an optical splitter, requiring no external energy, as long as there is input light. The beam splitter 30 is composed of entrance and exit slits, a mirror, and a dispersion element, and functions to separate a desired resonance absorption line. A conventional optical splitter 30 may split the optical fiber from 1 route into 8 routes, 16 routes, 32 routes, 64 routes, etc.

While 4 slave opto-electronic transceivers 40 are shown in fig. 2 of the present application, in other embodiments, N may have other values.

Each slave device 50 may make a communication connection with the master device 10 based on the slave opto-electronic transceiver 40, the splitter 30 and the master opto-electronic transceiver 20 connected to that slave device 50.

It can be seen that the number of optical fibers is reduced in the solution of the present application compared to the point-to-point connection in the conventional solution, at the distance from the main optical transceiver 20 to the optical splitter 30. For example, in fig. 1, the device 5 needs to use the optoelectronic transceiver 5, the optoelectronic transceiver 6, the optoelectronic transceiver 7, and the optoelectronic transceiver 8 to sequentially implement the connection with the optoelectronic transceiver 3, the optoelectronic transceiver 1, the optoelectronic transceiver 2, and the optoelectronic transceiver 4, and a total of 4 single-mode optical fibers are needed. In fig. 1, the main optical transceiver 20 only needs 1 single mode fiber to connect with the optical splitter 30, i.e. 3 fibers are reduced.

And it will be appreciated that the location of the optical splitter 30 and the respective slave opto-electronic transceivers 40 may be located closer to the respective slave devices 50.

In one embodiment of the present invention, the master device 10 may be specifically configured to:

the interrogation data is transmitted to the N slave devices 50 through the master opto-electronic transceiver 20, the splitter 30 and the N slave opto-electronic transceivers 40 such that a target slave device 50 of the N slave devices 50 to which the interrogation data is directed, after receiving the interrogation data, transmits feedback data to the master device 10 through the slave opto-electronic transceiver 40, the splitter 30 and the master opto-electronic transceiver 20 connected to the target slave device 50.

For example, in the embodiment of fig. 2, the master device 10 needs to send interrogation data to the device 1 via the master optoelectronic transceiver 20, although the interrogation data may be received by both slave devices 1 to 4, only the slave device 1 will send feedback data to the master device 10. After the other 3 slaves 50 have detected the inquiry data and found it not to be sent to themselves, no reply will be made.

Each device will be assigned a unique device address or device identifier, so that for each slave device 50, the slave device 50 can determine whether the inquiry data is sent to itself by the device address or device identifier carried in the inquiry data. Of course, in other embodiments, the determination may be made in other manners, for example, the data frame is provided with an area specifically indicating the data transmitting side and the data receiving side.

Since the optical splitter 30 is characterized in that the master transmission is received from all, and the slave transmission is received only by the master, when any slave device 50 transmits data to the master device 10, for example, when the slave device 1 transmits feedback data to the master device 10 through the slave optoelectronic transceiver 1, the optical splitter 30 and the master optoelectronic transceiver 20, the other slave optoelectronic transceivers 40 cannot receive the feedback signal.

In an embodiment of the present invention, for the master optoelectronic transceiver 20 or any one of the slave optoelectronic transceivers 40, the process of converting the electrical signal into the optical signal by the optoelectronic transceiver includes: according to a preset coding rule, coding the low-frequency electric signal into a high-frequency signal and then transmitting the signal through an optical fiber interface;

accordingly, for the master optoelectronic transceiver 20 or any one of the slave optoelectronic transceivers 40, the process of converting the optical signal into the electrical signal by the optoelectronic transceiver includes: and decoding the high-frequency signal received from the optical fiber interface into a low-frequency electric signal according to a preset decoding rule, and then transmitting the signal.

In this embodiment, it is considered that if the opto-electronic transceiver transmits 1 level or 0 level from the optical port for a long time, the opto-electronic transceiver may be automatically turned off due to excessive power, and the device may be burned out if the opto-electronic transceiver is not turned off. In practical application, the frequency of the electrical signal is low, so that any one of the optoelectronic transceivers of the present application needs to be encoded into a high-frequency signal before transmitting an optical signal, and correspondingly, after receiving the high-frequency optical signal, needs to be decoded into a low-frequency electrical signal, so that the optoelectronic transceiver does not transmit a 1 level or a 0 level from the optical port for a long time.

For example, in a specific embodiment of the present invention, the preset encoding rule may be:

The values of the first frequency and the second frequency can be set and adjusted according to actual needs, for example, in an embodiment of the present invention, the first frequency is 24MHz, and the second frequency is 96 MHz.

Fig. 4 is a schematic diagram of the encoded waveforms of Profibus-DP communication of the optoelectronic transceiver in one embodiment. In the embodiment of fig. 4, the low level of the modulated high-frequency signal is extended by 6 clock cycles, i.e., k is 6, at the falling edge of the Profibus-DP input signal, resulting in a low level with a length of 6 × 1/96MHz — 0.0625 us. And at the rising edge of the Profibus-DP input signal, the high level of the modulated high-frequency signal is elongated by 6 clock cycles to form a high level with a length of 6 × 1/96 MHz-0.0625 us. When the input signal of the Profibus-DP does not jump, the modulated high-frequency signal is a rectangular wave with the frequency equal to the first frequency, namely, the optical fiber interface continuously transmits a rectangular wave signal of 24MHz at the moment, which indicates that the level of the electric signal is not changed, and prevents the photoelectric transceiver from being automatically closed or burnt out.

In an embodiment of the present invention, the preset decoding rule may be:

the first frequency is used as a base frequency, and the second frequency is used as a counting clock.

When the low level duration of the high-frequency signal received from the optical fiber interface exceeds p clock cycles and does not exceed k clock cycles, pulling down the level of the decoded low-frequency electrical signal; when the high level duration of the high-frequency signal received from the optical fiber interface exceeds p clock cycles and does not exceed k clock cycles, pulling up the level of the decoded low-frequency electric signal; when the high level duration time of the high-frequency signal received from the optical fiber interface does not exceed p clock cycles and the low level duration time does not exceed p clock cycles, the level of the decoded low-frequency electric signal is kept unchanged; wherein k and p are positive integers and p is less than k.

Fig. 5 is a waveform diagram of the optical transceiver receiving the optical signal and decoding and outputting Profibus-DP in a specific case. In the embodiment of fig. 5, when the low level duration of the high frequency signal received from the optical fiber interface exceeds 4 clock cycles and does not exceed 6 clock cycles, it can be considered that the transmission level is changed from high to low, and therefore the level of the decoded low frequency electrical signal is pulled down, i.e., the Profibus-DP output port is pulled down.

Accordingly, when the high level duration of the high frequency signal received from the optical fiber interface exceeds 4 clock cycles and does not exceed 6 clock cycles, it can be considered that the transmission level is changed from low to high, and therefore, the level of the decoded low frequency electrical signal is pulled high, i.e., the Profibus-DP output port is pulled high.

When the time of both the high level and the low level received from the optical fiber interface does not reach 4 clock cycles, the level of the Profibus-DP is considered to be unchanged, and therefore, the level of the decoded low-frequency electric signal is kept unchanged.

In addition, when the high level duration or the low level duration of the high frequency signal received from the optical fiber interface exceeds 6 clock cycles, it may be considered that the communication is abnormal, and may trigger a fault handling mechanism, such as a flashing related indicator light, etc. In this example, p is 4, k is 6, and in other specific cases, k and p can be adjusted adaptively, without affecting the implementation of the present invention.

In one embodiment of the present invention, the receiving function and the transmitting function of the master optoelectronic transceiver 20 are both kept in an on state, and the receiving functions of the N slave optoelectronic transceivers 40 are both kept in an on state;

and for any one slave opto-electronic transceiver 40 of the N slave opto-electronic transceivers 40, after the slave opto-electronic transceiver 40 transmits feedback data to the master device 10, the slave opto-electronic transceiver 40 continues to transmit the rectangular wave of the first frequency until the slave opto-electronic transceiver 40 receives interrogation data not intended for the slave device 50 connected to the slave opto-electronic transceiver 40, the slave opto-electronic transceiver 40 stops transmitting the rectangular wave of the first frequency.

It is contemplated that the main opto-electronic transceiver 20 will turn off its receive function if the main opto-electronic transceiver 20 does not receive a signal from the opto-electronic transceiver 40 for a certain amount of time.

Therefore, in this embodiment of the present application, the receiving function and the transmitting function of the master optoelectronic transceiver 20 are both kept in the on state, and since after any one of the slave optoelectronic transceivers 40 transmits the feedback data to the master device 10, the slave optoelectronic transceiver 40 continues to transmit the rectangular wave of the first frequency until the slave optoelectronic transceiver 40 receives the query data not directed to the slave device 50 connected to the slave optoelectronic transceiver 40, the slave optoelectronic transceiver 40 stops transmitting the rectangular wave of the first frequency, and thus, it can be ensured that the master optoelectronic transceiver 20 does not turn off its receiving function.

For example, if the master optoelectronic transceiver 20 transmits the inquiry data a for the slave device 1, and after receiving the inquiry data a from each of the slave devices 1 to 4, only if the slave device 1 finds that the inquiry data a is specific to itself, the slave device 1 transmits the feedback data to the master device 10 through the slave optoelectronic transceiver 1, the optical splitter 30 and the master optoelectronic transceiver 20. After the feedback data is transmitted, the slave optoelectronic transceiver 1 still continuously transmits the 24MHZ rectangular wave, so that the master optoelectronic transceiver 20 does not turn off its receiving function.

For example, after a period of time, the master optoelectronic transceiver 20 transmits the query data B again, and assuming that the query data B is also for the slave device 1, the slave device 1 transmits the feedback data for the query data B to the master device 10 through the slave optoelectronic transceiver 1, the optical splitter 30 and the master optoelectronic transceiver 20, and continuously transmits the rectangular wave of 24MHZ after the feedback data is transmitted. It should be noted that, of course, since the optoelectronic transceiver needs to control the communication direction, the slave device 1 will turn off its transmitting function during the short time period for receiving the inquiry data B, that is, the master optoelectronic transceiver 20 will not receive the optical signal during the short time period, but the short duration will not cause the master optoelectronic transceiver 20 to turn off its receiving function.

For example, after a period of time, the master optoelectronic transceiver 20 transmits the query data C again, and assuming that the query data C is for the slave device 2, the slave device 2 transmits the feedback data for the query data C to the master device 10 through the slave optoelectronic transceiver 2, the optical splitter 30 and the master optoelectronic transceiver 20, and the slave device 2 continuously transmits the rectangular wave of 24MHZ after the feedback data is transmitted. On the other hand, after receiving the inquiry data C, the slave device 1 finds that the inquiry data C is not intended for itself, and therefore, the slave photoelectric transceiver 1 connected to the slave device 1 stops transmitting the rectangular wave of 24 MHZ.

It can be seen that the scheme of the present application ensures that both the receiving function and the transmitting function of the main photoelectric transceiver 20 can be kept in the on state, which is beneficial to ensuring continuous communication. In addition, in other embodiments, the on/off of the receiving function and the transmitting function of the main optoelectronic transceiver 20 may be controlled based on a program, but such a method may not be able to perform continuous communication because the on/off of the receiving function and the transmitting function of the optoelectronic transceiver takes a long time.

In addition, in this embodiment of the present application, after the master device 10 sends the inquiry data, only one corresponding slave device 50 replies, that is, sends the feedback data, and at the same time, the situation that a plurality of slave devices 50 send the rectangular wave of the first frequency does not occur, so on the premise that the master optoelectronic transceiver 20 can receive the optical signal without closing the receiving function of the master optoelectronic transceiver 20, the situation that the master optoelectronic transceiver 20 receives signals of a plurality of slave optoelectronic transceivers 40 at the same time to cause overload reception and cannot distinguish the normal signal is avoided.

It should be noted that, since the slave optoelectronic transceiver 40 needs to control the communication direction, in practical applications, for example, a simple arbitration mechanism may be used to determine the current communication direction of the slave optoelectronic transceiver 40. For example, the slave opto-electronic transceiver 40, upon being powered up, enters an arbitration state awaiting a determination of whether the Profibus-DP signal is active or the fiber optic signal is active. Specifically, when it is determined that the Profibus-DP signal has a falling edge, the Profibus-DP signal is determined to be valid, and the slave optoelectronic transceiver 40 converts the Profibus-DP signal in the IO-BUS into an optical signal, that is, receives the electrical signal from the optoelectronic transceiver 40 and converts the electrical signal into an optical signal. Accordingly, if the optical signal is asserted when a falling edge occurs after entering the arbitration state, the slave opto-electronic transceiver 40 converts the optical signal to a Profibus-DP signal. When a complete packet of data is forwarded, the arbitration state is returned.

In an embodiment of the present invention, referring to fig. 6, the method may further include:

a class ii main photoelectric transceiver 60 connected to the main device 10 through a cable;

connecting the second-type slave photoelectric transceiver 70 with the second-type master photoelectric transceiver 60 through an optical fiber, and connecting the second-type slave photoelectric transceiver 70 with the M slave devices 50 through cables, wherein each slave device 50 in the M slave devices 50 is connected with the master device 10 on the basis of the second-type slave photoelectric transceiver 70 and the second-type master photoelectric transceiver 60; m is a positive integer not less than 2.

It should be noted that the second type of main optical transceiver 60 is only used for distinguishing from the aforementioned main optical transceiver 20, and the two types of main optical transceivers may be devices of the same type or different types, which do not affect the implementation of the present invention. Similarly, the two types of slave optoelectronic transceivers 70 are only used to distinguish them from the N slave optoelectronic transceivers 40 in the foregoing.

This embodiment of the present application is generally directed to the situation where the slave device 50 is closer to the master device 10, and therefore the master device 10 is connected to the M slave devices 50 through one class ii master optoelectronic transceiver 60 and one class ii slave optoelectronic transceiver 70.

In contrast to the conventional solutions, in which a cable connection is directly used, the devices 5, 6 in fig. 1 transmit signals to the equipment 5 using a cable, for example. The device 5 and the device 6 are not connected by optical fibers, and directly transmit signals to the equipment 5 by cables. In practice, it is acceptable for the device to have a small number of signals, but when the number of signals is large, for example, a device in a large factory can have more than 500 signals at most, a considerable number of cables are required.

In the embodiment of fig. 6 of the present application, the secondary optoelectronic transceiver 70 is connected to the primary optoelectronic transceiver 60 through an optical fiber, which is beneficial to reducing the number of cables used. Moreover, when the cables are used for transmitting fieldbus signals, the application of a large number of cables also reduces the environmental protection of construction projects, and in addition, electrical signals are also easily interfered, intercepted and intercepted in the transmission process, so that the safety and reliability of the signals are reduced.

The photoelectric transceiving system of the industrial field bus based on the optical fiber network, which is provided by the embodiment of the invention, comprises: a master device 10; a main photoelectric transceiver 20 connected to the main device 10 through a cable; an optical splitter 30 connected to the main optical transceiver 20 through an optical fiber; n slave opto-electronic transceivers 40 connected to the optical splitter 30 by optical fibers; n is a positive integer not less than 2; n slave devices 50 connected to the N slave opto-electronic transceivers 40 by cables, respectively, and each slave device 50 makes a communication connection with the master device 10 based on the slave opto-electronic transceiver 40, the optical splitter 30, and the master opto-electronic transceiver 20 connected to the slave device 50.

Those of skill would further appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both, and that the various illustrative components and steps have been described above generally in terms of their functionality in order to clearly illustrate this interchangeability of hardware and software. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

The principle and the implementation of the present invention are explained in the present application by using specific examples, and the above description of the embodiments is only used to help understanding the technical solution and the core idea of the present invention. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention.

Claims

1. An optical-electrical transceiver system of an industrial field bus based on an optical fiber network, comprising:

a master device;

a main optoelectronic transceiver connected to the main device by a cable;

the slave device comprises N slave devices which are respectively connected with N slave photoelectric transceivers through cables, and each slave device realizes communication connection with the master device based on the slave photoelectric transceiver connected with the slave device, the optical splitter and the master photoelectric transceiver;

for the master optoelectronic transceiver or any one of the slave optoelectronic transceivers, the process of converting the electrical signal into the optical signal by the optoelectronic transceiver comprises: according to a preset coding rule, coding the low-frequency electric signal into a high-frequency signal and then transmitting the signal through an optical fiber interface;

correspondingly, for the master optical-electrical transceiver or any one of the slave optical-electrical transceivers, the process of converting the optical signal into the electrical signal by the optical-electrical transceiver includes: decoding the high-frequency signal received from the optical fiber interface into a low-frequency electric signal according to a preset decoding rule, and then sending the signal;

the preset encoding rule is as follows:

2. The optical-fiber-network-based industrial fieldbus optoelectronic transceiver system of claim 1, wherein the preset decoding rule is:

3. The optical-electrical transceiver system of an industrial fieldbus based on an optical fiber network as claimed in claim 1, wherein the master device is specifically configured to:

4. The optical fiber network-based industrial fieldbus optoelectronic transceiver system of claim 3, wherein the receiving function and the transmitting function of the master optoelectronic transceiver are both kept in an on state, and the receiving functions of the N slave optoelectronic transceivers are both kept in an on state;

5. The fiber optic network-based optoelectronic transceiver system of industrial fieldbus according to claim 2, wherein the first frequency is 24MHz and the second frequency is 96 MHz.

6. The optical-electrical transceiver system for industrial fieldbus based on optical fiber network according to any one of claims 1 to 5, further comprising: