KR100237613B1 - Remote redundant system and control method in plc - Google Patents

Abstract

The present invention relates to a PRC remote redundancy system and a control method. In the related art, a remote slave unit (RSU) can receive data from a master station when the master station is powered off or when communication is lost due to disconnection of a communication line. Therefore, the output data finally received just before the communication interruption can be output through the output module, so it is impossible to control the output value of the remote station in case of emergency such as communication interruption, and to control the input and output in case of abnormal status of the remote station. In addition, there is a problem that the reliability of the remote system is deteriorated because false data due to noise is outputted to the output module without being filtered when it is transmitted through communication. Therefore, the present invention provides two modems (1) (1 ') for data communication with a counterpart station via a communication cable; A transmission / reception module (2) for performing data transmission and reception with a master station by a predetermined protocol; An output data storage section 4 for receiving and storing data to be output to the output card at the master station; An input data storage unit 6 for reading and storing input data from the input module; An emergency output data storage unit 5 for setting and storing an emergency output value; An input / output control module 7 for outputting data to or receiving data from an input / output module I / 0 of a remote station, and controlling input / output card information and attachment / detachment; The system is configured with redundancy using the input / output module 8 which actually performs external device control, and interlock devices are inserted between the remote slave units configured as redundant to monitor each other so that no error data is output in the abnormal state. It prevents malfunctions and improves reliability.

Description

PRC remote redundancy system and control method

The present invention relates to a PRC remote redundancy system in which a remote slave unit of a remote station is configured in redundancy and exchanges and checks mutual data between the duplicated units so as to prevent a malfunction by not receiving data when an abnormal state occurs. In particular, the present invention relates to a PRC remote redundancy system and a control method for improving reliability of a remote system by inserting interlock devices between redundant remote slave units to monitor each other.

When configuring a control system using PLC, if the PLC and I / O module are needed at a long distance, the remote slave unit combines the communication function and the I / O control function without installing the PPC and the communication module. Since it is economical to install (RSU), the remote slave unit (RSU) has been widely used for the input / output expansion application of PPC CPI and the remote input / output control application.

The configuration of a communication system consisting of a conventional link master station and a remote slave unit (RSU) used for the same purpose as described above is, as shown in FIG. 1, a module mounted on a PLC (PLC) master station on a network. A master station (M1) consisting of a link station (LINK) and an input / output module (I / O) for controlling all input / output contacts on the network as well as having a communication right and controlling its input / output contacts; To the remote station (S1, S2, S3, ..., Sn) composed of n remote slave units (RSU) for controlling its input / output module (I / O) through data communication with the master station (M1). It is composed.

In the above, the remote slave unit (RSU) includes a modem (1) for data communication with a counterpart station via a communication cable, as shown in FIG. A transmission / reception module (2) for performing data transmission and reception with a master station by a predetermined protocol; An output data storage section 4 for receiving and storing data to be output to the output card at the master station; An input data storage unit 5 for reading and storing input data from the input module; An input / output control module 6 for outputting and inputting data to and from the remote station's input / output module (I / O), and controlling input / output card information and removal items; It consists of the input / output module 7 which actually performs external device control.

Looking at the prior art configured as described above in detail.

The link station (LINK) of the master station (M1) is a link module installed in the PLC and acts as a master station (M1) on the network and has a communication right, and the remote slave unit (RSU) of up to n stations is connected. It can be set as a slave station, and the remote slave unit (RSU) sets its own station number and master station in hardware and receives data from the master station M1 to exchange data with the master station.

Referring to FIG. 2, the data output sequence of the remote slave unit RSU to the output module will be described. First, the transmission / reception module 2 receives data received from the master station M1 via the modem 1 through a transmission / reception buffer ( 3) it is stored in the output data storage unit (4).

Then, the input / output control module 6 reads the data received and stored in the output data storage unit 4 and outputs the stored data to the output module of the input / output module 7.

In contrast to the above, in the process of receiving data from the input module, the input / output control module 6 reads an external input value from the input module of the input / output module 7 and stores it in the input data storage unit 5. .

Then, the transmission / reception module 2 transfers the data of the input data storage unit 5 to the transmission / reception buffer 3 and transmits the data to the master station M1 through the modem 1 when the transmission request of the master station M1 is made.

As described above, the remote stations S1, S2, S3, ..., Sn perform data input / output to their I / O module 7, and the master station M1 sets the remote stations S1, S2, I / O data can be transmitted / received by sequentially communicating with S3, ..., Sn, so remote I / O control is possible by using remote slave unit (RSU) of several stations as its remote I / O module (I / O_). Do.

However, in the prior art as described above, the remote slave unit (RSU) cannot immediately receive data from the master station when the master station is disconnected from the remote station or when communication is lost due to disconnection of the communication line. In case of emergency such as communication loss, the output value of remote station cannot be controlled.In case of abnormal state of remote station, input / output cannot be controlled. When the false data is transmitted to the communication module as it is output to the output module as it is without filtration, there is a problem that reduces the reliability of the remote system.

Accordingly, an object of the present invention for solving the conventional problems as described above is to configure a remote slave unit (RSU) in redundancy, exchange and check data between the duplicated remote slave units, and thereby It is to provide a PRC remote redundancy system and control method to prevent the system malfunction by preventing the output.

Another object of the present invention is to insert an interlock device between redundant remote slave units to monitor each other so that the data of the remote station is not output in the case of a power failure of the master station or a communication breakdown due to disconnection of a communication line. In order to improve the reliability of the remote station, PLC's remote redundancy system and control method are provided.

1 is a diagram of a communication system consisting of a conventional link master station and a remote slave unit (RSU).

2 is a detailed block diagram of a remote slave unit (RSU) in FIG.

3 is a schematic diagram of a PRC remote redundancy system according to the present invention.

4 is a block diagram of an interlock device for monitoring during redundancy operation between a remote slave unit and a remote slave unit.

5 is an operation process diagram for a PRC remote redundancy control method of the present invention.

* Explanation of symbols for main parts of the drawings

1,1 ′: modem 2: transmission / reception module

3: transmission / reception buffer 4: output data storage unit

5: emergency output data storage 6: input data storage

7: I / O control module 8: I / O module

11,11 ': interlock signal generator 12,12': controller

13,13 ′: shared ram CO: interface cable

In order to achieve the above object, the present invention relates to a PRC remote redundancy control method. As shown in FIG. 5, when the data is transmitted / received between a master station and a remote station comprising a plurality of duplicated remote slave units, Determining a primary and secondary remote slave unit in the slave unit; A second step of comparing the received data with the secondary remote slave unit if there is received data after determining the primary and secondary remote slave units in the first step; A third step of processing data if the two data received by the housewife remote slave unit are the same in the second step, and requesting retransmission to the master station if different; A fourth step of checking whether there is transmission data to the master station; a fifth step of transmitting if there is transmission data in the fourth step; and a fifth step of checking the status of the remote slave unit of the other party using an interlock device if there is no transmission data. Steps; If there is an abnormality in the fifth step, the sixth step is performed so that the present situation can be reported to the master station to deal with.

In this way, the PRC remote redundancy system configuration of the present invention for performing the method consisting of each step includes two modems (1) (1) for performing data communication with the other station via a communication cable, as shown in FIG. ')and; A transmission / reception module (2) for performing data transmission and reception with a master station by a predetermined protocol; An output data storage section 4 for receiving and storing data to be output to the output card at the master station; An input data storage unit (6) for reading and storing input data from an input module when transmitting data to the master station; An emergency output data storage unit 5 for setting and storing an output value to be transmitted to the master station in an emergency; An input / output control module 7 for outputting data to or receiving data from an input / output module (I / O) of a remote station, and controlling input / output card information and attachment / detachment; It consists of the input / output module 8 which actually performs external machine control.

The interlock device inserted between the redundant remote slave unit and the remote slave unit to monitor each other is generated by generating an interlock signal for notifying when a communication breakdown or abnormal condition occurs, as shown in FIG. An interlock signal generator 11; A control unit 12 which receives an interlock signal through a cable and detects an abnormal state of a counterpart remote slave unit and compares input / output data; The control unit 12 is configured as a common Lang 13 for storing the data to be compared.

Referring to the operation and effect of the present invention configured as described in detail as follows.

The remote slave unit RSU of the remote station stores the data received at the master station M1 via the modem 1 or another modem 1 'in the transmission / reception buffer 3 via the transmission / reception module 2.

The transmission / reception module 2 stores the received data in the output data storage unit 4 when the received data is output data, and in the emergency output data storage unit 5 in the case of emergency output data.

On the contrary, when transmitting to the master station, the transmission / reception module 2 transfers the data stored in the input data storage unit 6 to the transmission / reception buffer 3 and the modem 1 or another modem 1 'when the master station transmits a request. ) Send the input value to the master station through both. In the normal operation, the input / output control module 7 outputs the data of the output data storage unit 4 to the output module constituting the input / output module 8, and vice versa from the input module constituting the input / output module 8. The input value is read and stored in the input data storage section 6 so that the transmission / reception module 2 can transmit to the master station.

By the same procedure as above, the master station can control the input / output contact of the remote slave unit (RSU) of the remote station.

In this way, a remote station having a redundant Remote Slave Unit (RSU) needs to be monitored to ensure that data is not exchanged when the master station loses power or an abnormal condition occurs.

Therefore, an interlock device is inserted to monitor each other between the redundant remote slave unit and another remote slave unit (RSU).

The operation of the interlock device inserted as described above will be described with reference to FIG.

When one of the remote slave units (RSU1) configured as duplex cannot receive data from the master station when the power of the master station is cut off or the state of communication interruption due to disconnection of the communication line is performed, the remote slave unit (RSU1) The interlock signal generating unit 11 of the interlock device generates and generates an interlock signal to indicate that an abnormal state has occurred.

The interlock signal is then read from the interlock device of the counterpart remote slave unit RSU2 via the interface cable.

The interlock signal thus read is input from the control unit 12 'to detect the occurrence of an abnormal state.

Therefore, the controller 12 ′ detects an abnormal state of the remote slave unit RSU1 and does not exchange data with the unit RUS1 to prevent malfunction.

Then, when the user operates normally, the remote slave unit RSU1 and the other remote slave unit RSU2 exchange data received from the master station with each other.

At this time, the comparison operation is performed by the control unit 12 (12 ') of the interlock device, and the received data is stored in the common RAM 13 (13') and compared using the stored data.

As a result of the comparison, if the data is the same, the received data is used. If the data are not the same, the received data is requested from the master station again, received, compared, and processed.

As described above, when a communication line breakage or an abnormal state of one remote slave unit occurs, another remote slave unit configured as redundancy is detected as a signal from the interlock device so that there is no problem in communication.

At this time, the interlock device improves the reliability of the entire remote communication system by comparing data in real time.

And, in the above data exchange between one remote slave unit RSU1 and another remote slave unit RSU2, one unit becomes the primary remote slave unit RSU and the other becomes the secondary remote slave unit RSU. .

In addition, two communication lines are initially tested, and one communication line is selected to establish a communication line for communication.

As described above, the present invention improves the reliability of the output data by configuring the slave unit of the remote station in redundancy, and inserts an interlock device for abnormal state detection and malfunction so that the data can be compared and processed in real time to ensure the reliability of the entire communication system. There is an effect to improve the.

Claims (5)

In the remote slave unit (RSU), which has a communication function through a modem and an input / output control function, two or more modems for performing data communication with a counterpart station through a communication cable and an output value for informing the counterpart station in case of emergency are outputted. And a data storage unit further included in the remote slave unit to configure a redundant system. The PRC remote redundancy system according to claim 1, wherein the remote slave unit is configured to operate by designating one as the primary RSU (remote slave unit) and the other as the secondary RSU during data communication with another remote slave unit. 2. The PRC remote redundancy system according to claim 1, wherein an interlock device is inserted between the redundant remote slave units to exchange data with each other, and to check and prevent false output. 4. The apparatus of claim 3, wherein the interlock device comprises: an interlock signal generator for generating and generating an interlock signal for notifying when a communication breakdown or abnormal condition occurs; A control unit which receives an interlock signal through a cable and detects an abnormal state of a counterpart remote slave unit and compares input / output data; And a common RAM for storing data to be compared in the control unit. A first step of determining primary and secondary remote slave units in the plurality of redundant remote slave units when transmitting and receiving data between a remote station and a master station including a plurality of redundant remote slave units; A second step of comparing the received data with the secondary remote slave unit if there is received data after determining the primary and secondary remote slave units in the first step; A third step of processing data if two data received by the primary and secondary remote slave units are the same in the second step, and requesting retransmission to the master station if different; A fourth step of checking whether there is transmission data to the master station; a fifth step of transmitting if there is transmission data in the fourth step; and a fifth step of checking the status of the remote slave unit of the other party using an interlock device if there is no transmission data. Steps; And a sixth step of reporting the current status to the master station to cope with the abnormality in the fifth step.

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