KR20010018873A - Method for Building a Control Network of Distributed Control Systems and System Thereof - Google Patents

Abstract

PURPOSE: A system for configurating a control communication network of a distributed control system is provided to interpose a PST(Physical layer Service Translator) between a MAC(Media Access Control) sub layer of an IEEE(Institute of Electrical and Electronics Engineering)802.4 token transmission bus communication agreement and a physical layer of a carrier sensing multiple access communication agreement using an IEEE802.3 collision detection, so as to combine physical layers. CONSTITUTION: A MAC(Media Access Control) sub layer(10) is an IEEE(Institute of Electrical and Electronics Engineering)802.4 token transmission bus communication agreement. A physical layer(20) is a carrier sensing multiple access communication agreement using an IEEE802.3 collision detection. A PST(Physical layer Service Translator)(30) is interposed between the MAC sub layer(10) and the physical layer(20). The PST(30) combines codes of two communication systems according to order, by using an encoding system and a decoding system.

Description

Method for Building a Control Network of Distributed Control Systems and System Thereof}

The present invention relates to a method for constructing a control network of a distributed control system combining a media access control method of the Institute of Electrical and Electronics Engineering (IEEE) 802.4 standard and a physical layer standard of the IEEE 802.3 standard.

Distributed control system is an important facility that is used in many industrial sites such as factories and power plants. The control communication network, which constitutes a distributed control system, is of great importance.

As is known, distributed controllers in a distributed control system are connected via a communication network. The communication network connecting these distributed controllers is called a control communication network. The control network must provide real-time performance and high reliability in the transmission of data. In addition, urgent messages should be transmitted within a predetermined time limit, and the cost of the communication network should be considered at the same time. The IEEE 802.4 token transfer bus approach is widely used in control networks for distributed control systems because it achieves real-time performance and deterministic data transfer performance. However, it is very expensive to implement and maintain. The IEEE 802.3 communication method is widely used, so the cost of the communication network is low, but the media access control method is not suitable for real-time applications.

The condition of the distributed control system in Korea is not properly secured the design technology of its own control communication network. Common standards for the control network of distributed control systems include the IEEE 802.4 token transfer bus protocol and the carrier sensing multiple access protocol using IEEE 802.3 collision detection. Among them, the IEEE 802.4 token transfer bus approach can achieve real-time performance and deterministic data transfer performance, but it is expensive to implement and maintain. The IEEE 802.3 communication protocol is widely used, so the cost of the communication network is low, but the media access control method is not suitable for real-time applications.

An object of the present invention is to implement an industrial communication network that satisfies real-time performance and low communication network cost.

The present invention provides a token access bus type media access control method of IEEE 802.4 standard specification and IEEE 802.3 which is low in cost of establishing and maintaining a network in order to realize an industrial communication network that satisfies real-time performance and has a low network cost. The technical challenge is to combine the strengths of the two standards by combining the physical media conventions of the standard.

The present invention provides a physical layer service translator between a media access control sublayer of the IEEE 802.4 token transfer bus protocol and a physical layer of carrier sensing multiple access protocol using IEEE 802.3 collision detection to combine two different communication schemes. Physical layer service translator (PST) through the physical layer is characterized in that the coupling.

1 is a block diagram of a communication network of the present invention

2 is a diagram of a combination of two consecutive IEEE 802.3 physical layer signals of the present invention.

3 is a diagram of a unique encoding scheme 1 used for combining two communication schemes of the present invention.

4 is an explanatory diagram of a unique encoding scheme 2 used for combining two communication schemes of the present invention.

5 is an explanatory diagram of a unique decoding scheme 1 used for combining two communication schemes of the present invention.

6 is an explanatory diagram of a unique decoding scheme 2 used for combining two communication schemes of the present invention.

7 is a circuit diagram for implementing a physical layer service converter of the present invention.

8 is an explanatory diagram of input and output signal names of a physical layer service converter of the present invention;

9 is an embodiment of a control communication network using the communication network of the present invention.

<Code Description of Main Parts of Drawing>

10: IEEE 802.4 medium access control sublayer 20: IEEE 802.3 physical layer

30: physical layer service converter 31: station manager

32: clock controller 33: medium access control mode transmitter

34: medium access control mode receiver 35: receiver blank signal generator

36: indication signal multiplexer

As shown in FIG. 1, the present invention provides a physical connection between the media access control sublayer 10 of the IEEE 802.4 token transfer bus communication protocol and the physical layer 20 of the carrier sensing multiple access communication protocol using IEEE 802.3 collision detection. Combining the physical layer via the layer service converter 30, and for the combination of the two communication schemes, the sign of the continuous IEEE 802.3 physical layer 20 having a duration of 100 ns and a frequency of 10 MHz is shown in FIG. Combined as in (a), one IEEE 802.4 medium access control sublayer 10 code having a duration of 200 ns and a frequency of 5 MHz is formed.

The physical layer service converter 30 has a unique encoding scheme 1 as shown in FIG. 3, a coding scheme 2 as shown in FIG. 4, and a decoding scheme 1 as shown in FIG. 5 to combine the two communication schemes. It implements the decryption scheme 2 as shown.

The encoding scheme 1 is used together with the decoding scheme 1, and the encoding scheme 2 is used together with the decoding scheme 2.

In order to implement the physical layer service converter 30, as shown in FIG. 7, a station manager (SMANAGER: module providing a connection function with a media controller) 31 and a clock controller (CLKCTRL) adjust time synchronization and speed. A module for adjusting the difference 32, a medium access control mode transmitter (MACTX: a module for generating a transmission signal using a unique coding scheme) 33, and a medium access control mode receiver (MACRX: a unique decoding scheme). Module 34 for analyzing the received signal using the receiver, a receiver blank signal generator (RBLK: a module in charge of processing after completion of each transmission) 35, and an indication signal multiplexer (INMUX: received data according to communication status). Module 36 to control the selection of the PHY, and the physical layer service converter 30 has an input / output signal as shown in FIG. 8, in the description of FIG. 8, the PST is a physical layer service converter and the MAC is IEEE 802.4. Media access control department Layer, PHY, is the IEEE 802.3 physical layer part.

As such, the physical layer service converter 30 of the present invention connects the media access control sublayer 10 of the IEEE 802.4 token transfer bus communication protocol and the physical layer 20 of the IEEE 802.3 standard, which are two communication methods that cannot be directly connected. The codes of two consecutive IEEE 802.3 physical layers 20 are combined to form one IEEE 802.4 medium access control sublayer 10 code. At this time, if the order of the codes of two consecutive IEEE 802.3 physical layers 20 is changed, an incorrect IEEE 802.4 medium access control sublayer 10 code is generated (see FIG. 2 (b)), so that the physical layer service converter 30 Must be able to find the correct order of the codes of two consecutive IEEE 802.3 physical layers 20. To this end, the physical layer service converter 30 combines the codes of the two communication schemes in order using an encoding scheme and a decoding scheme. As a suitable coding method and decoding method, coding method 1, coding method 2 and decoding method 1, and decoding method 2 are used. Encoding method 1 is used together with decoding method 1, and encoding method 2 is used together with decoding method 2. The encoding scheme 1 and the encoding scheme 2 use the codes silence, pad_idle, zero, one, and non_data of the media access control sublayer 10 of the IEEE 802.4 token transfer bus communication protocol in the physical layer 20 of the IEEE 802.3 standard. It is a rule to convert IDL (idle), CD1 (clocked data one), and CD0 (clocked data zero). In addition, decoding method 1 and decoding method 2 use IDL, CD1, CD0, and CARRIER_STATUS, SIGNAL_STATUS, which are the physical layer 20 codes of the IEEE 802.3 standard, to code the media access control sublayer 10 of the IEEE 802.4 token transfer bus communication protocol. This rule converts zero, one, bad_signal, non_data, and silence. In this case, X in FIG. 5 and FIG. 6 indicates don't care. The out of sequence indicates a case where the order of the physical layer 20 code pairs is not correct.

As described above, the physical layer service converter of the present invention combines the codes of the two communication methods in order using the configuration, the encoding method, and the decoding method as shown in FIG. 7 to connect the two communication methods. The station management controller 31 Controls the station management mode and the media access control mode, which are modes of the communication network. The receive and transmit clock controller 32 selects a receive clock from a clock input source to generate a receive clock, controls the phase of the received data and generates a transmit clock. The medium access control mode transmitter 33 encodes a request signal of the medium access control sublayer 10 to generate a physical layer 20 signal for the transmitter. The medium access control mode receiver 34 generates a signal of the medium access control sublayer 10 by decoding the physical layer 20 signal according to the signal on the anti-clock. Receiver blank signal generator 35 allows medium access control mode receiver 34 to perform receiver blanking logic. The indication signal multiplexer 36 selects a management mode indication signal and a medium access control indication input according to the mode.

<Example>

The present invention can be implemented in the control communication network of the distributed control system as shown in FIG. In an embodiment, the inventive IEEE 802.4 media access control sublayer 10, the physical layer service converter 30, and the IEEE 802.3 standard physical layer 20 constitute the data link layer 40 and the physical layer. Together with an application program interface (API) 50, an application layer (AL) 60, and a network management (NM) 70 to form a control communication network of a distributed control system.

According to the present invention, by using the physical layer of the widely used IEEE 802.3 communication method, it is possible to reduce the installation, maintenance, and maintenance costs of the communication network than when using the IEEE 802.4 communication network, and to use the IEEE 802.4 token transfer bus method as a medium access control method. By using it, it provides functionality to meet real-time performance and decisive operation and priority schemes required for industrial communication networks.

In addition, the communication network structure of the present invention is a structure that can efficiently configure the control communication network by combining the advantages of the IEEE 802.4 token transfer bus approach and the IEEE 802.3 communication protocol. This structure is a new approach, and the advantage of utilizing resources such as hardware or software for the existing communication network, and the design can be widened in the network system design, making a great contribution to securing network technology for control of distributed control system It is expected that the results of the present invention can be readily applied to industrial sites.

Claims (5)

A physical layer service converter 30 is interposed between the media access control sublayer 10 of the IEEE 802.4 token transfer bus communication protocol and the physical layer 20 of the carrier sensing multiple access communication protocol using the IEEE 802.3 collision detection protocol. The physical layer service converter (30) is a method for constructing a control network of a distributed control system, characterized in that by using the coding scheme and decoding scheme to combine the codes of the two communication schemes in order. 2. The IEEE 802.4 medium access control unit according to claim 1, wherein the code of consecutive IEEE 802.3 physical layer 20 having a duration of 100 ns and a frequency of 10 MHz has a duration of 200 ns and a frequency of 5 MHz. A method for constructing a control communication network of a distributed control system, characterized by comprising a layer (10) code. The method of claim 1, wherein the encoding scheme 1 is used together with the decoding scheme 1, and the encoding scheme 2 is used together with the decoding scheme 2. The encoding scheme 1 and the encoding scheme 2 are coded by the IEEE 802.3 standard, the code silence, pad_idle, zero, one, and non_data of the media access control sublayer 10 of the IEEE 802.4 token transfer bus communication protocol. It is a rule that converts IDL (idle), CD1 (clocked data one), and CD0 (clocked data zero), which are codes used in the physical layer 20 of the scheme, and the decoding scheme 1 and the decoding scheme 2 are physical layers of the IEEE 802.3 standard. (20) It is a rule that converts IDL, CD1, CD0 and CARRIER_STATUS, SIGNAL_STATUS, which are codes, into zero, one, bad_signal, non_data, and silence, which are codes of the media access control sublayer 10 of the IEEE 802.4 token transfer bus communication protocol. Control communication network configuration method of a distributed control system. A physical layer service translator 30 is interposed between the media access control sublayer 10 of the IEEE 802.4 token transfer bus communication protocol and the physical layer 20 of the carrier sensing multiple access communication protocol using the IEEE 802.3 collision detection protocol. Station manager 31, clock controller 32, media access control mode transmitter 33, media access control mode receiver 34, and receiver blank signal generator 35 to implement the layer service converter 30. And an indication signal multiplexer (36).