JP2007323457A - Data transmission method of duplexed controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a data transmission method of duplexed controllers capable of simplifying hardware for transmitting data between the duplexed controllers. <P>SOLUTION: In order to equalize the data of the master controller and the slave controller of the duplexed controllers, scan transmission of a network is used. Thus, the same function is realized without using a module or a cable for tracking. Thus, hardware constitution is simplified, and it is effective for product cost reduction and storage space reduction as well. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a data transmission method of a duplex controller for equalizing data between duplex controllers.

  Controllers used in industrial applications such as petrochemical, steel, pulp, and food plant monitoring and control systems, and controllers used in public applications such as water and sewage, road, airport, and building monitoring systems In order to maintain high reliability, the equipment is duplicated to achieve continuous operation. It is necessary to equalize data between duplicated controllers, for example, a master controller and a slave controller.

  FIG. 3 is a configuration diagram of a typical monitoring and control system including a duplexed controller. The duplicated controllers 11 a and 11 b are connected to the control LAN 12, transmit data to an HMI (Human Machine Interface) 13, and receive an operation command from the HMI 13. On the other hand, the controllers 11a and 11b are connected to the process input / output unit (PIO unit) 14 by process input / output signal cables 15a and 15b, and take in process signals from the plant via the PIO unit 14. In addition, an operation signal is output to the actuator (operation end) of the plant via the process input / output signal cables (PIO cables) 15a and 15b and the PIO unit 14.

  The duplicated controllers 11a and 11b are composed of power supplies 16a and 16b, CPUs 17a and 17b, tracking cards 18a and 18b, and network interfaces 19a and 19b, respectively, and can execute the same function.

  Usually, since a standby redundant system is formed, one becomes the master controller 11a and the other becomes the slave controller 11b. When the master controller 11a is normal, the master controller 11a performs online control, and when the master controller 11a becomes abnormal, the standby slave controller 11b is online and continues control.

  In order to continue the control smoothly from the master controller 11a to the slave controller 11b, it is necessary to always transmit the data held by the master controller 11a to the slave controller 11b. We are transmitting.

  Next, the PIO unit 14 includes a power supply 21, a CPU interface 22, a digital input / output card 23, an analog input / output card 24, a pulse input / output card 25, and a contact input / output card 26.

  Signals for monitoring the plant status are from various sensors, digital input is the digital input / output card 23, analog input is the analog input / output card 24, pulse input is the pulse input / output card 25, and contact input is the contact input / output card 26. Via the controller.

In addition, operation signals for controlling the plant are sent from the controllers 11a and 11b.
The digital output is output to various actuators via the digital input / output card 23, the analog output is output via the analog input / output card 24, the pulse output is output via the pulse input / output card 25, and the contact output is output via the contact input / output card 26.

Since the controllers 11a and 11b are duplicated, the CPU interface 22 of the PIO unit 14 can communicate through the CPU 17a of the master controller 11a and the PIO cable 15a and through the CPU 17b of the slave controller 11b and the PIO cable 15b. The data transmission method between the controllers 11a and 11b and the PIO unit 14 is a method in which the CPUs 17a and 17b periodically access PIO data.

Here, by enabling I / O input / output to / from one P / O input / output device from multiple controllers, system cost is reduced, mounting efficiency is improved, and system construction flexibility is increased. Some have improved (for example, refer to Patent Document 1).
JP 2002-82896 A

  However, since the data transmission method between the controllers 11a and 11b and the PIO unit 14 is a method in which the CPUs 17a and 17b periodically access PIO data, the tracking cards 18a and 18b and the tracking cable 20 are required. For this reason, simplification of the hardware configuration for data transmission between the duplicated controllers 11a and 11b is desired.

  An object of the present invention is to provide a data transmission method of a duplex controller that can simplify hardware for data transmission between the duplex controllers.

  The duplex controller data transmission method of the present invention is characterized in that network scan transmission is used to equalize data between the master controller and the slave controller of the duplex controller.

  According to the present invention, the same function can be realized without using a tracking module or cable by using the scan transmission as the data transmission method of the duplicated controller and taking the online data into the local station. . Therefore, the hardware configuration is simplified, which is effective for reducing the cost of the product and the storage space.

  FIG. 1 is a system configuration diagram for realizing a data transmission method of a duplex controller according to an embodiment of the present invention. In the embodiment of the present invention, the scan transmission method is adopted as the data transmission method between the controllers 11a and 11b and the PIO unit 14. For this reason, the tracking cards 18a and 18b and the tracking cable 20 which are conventionally required are no longer necessary.

  Here, the scan transmission method is a function for simultaneously writing the information of its own station to each station connected to the network by applying broadcast transmission, and each station connected to the network can automatically capture the information of other stations. It can be done. This scan transmission method is a technology that has been cultivated in the control LAN, but it can be used for transmission between the controller and the PIO unit due to the development of electronic technology.

  As described above, in the conventional example shown in FIG. 3, the CPUs 17 a and 17 b write data to the PIO unit 14 and perform reading at regular intervals. Therefore, for duplication, the data and online internal data are transmitted to the standby system via the tracking cards 18a and 18b.

  On the other hand, in the present invention, scan transmission is adopted for transmission between the CPUs 17a and 17b and the PIO unit. This eliminates the need for periodic data reading and data writing from the CPUs 17a and 17b. Further, the data of the PIO unit 14 is automatically written in the CPUs 17a and 17b at the scan transmission cycle.

  By using this scan transmission function to place online internal data in the scan transmission area, the standby CPU 17b can automatically obtain online internal data as a result.

  FIG. 2 is an explanatory diagram of the operation by the data transmission method of the duplex controller according to the embodiment of the present invention. This shows a system composed of duplicated controllers 11a and 11b and two PIO units 14a and 14b. The controllers 11a and 11b and the PIO units 14a and 14b have scan memories 27a to 27d, respectively, and are drawn out by arrows in FIG. For example, when the master controller 11a writes its own data in A1 of the scan memory 27a, the data written by the master controller 11a is automatically transferred to A2, A3, and A4 of the scan memories 27b, 27c, and 27d by scan transmission. Is done.

  Similarly, if the PIO unit 14a writes its own data to C2 of the scan memory 27b, the data of the PIO units 14a and 14b is automatically transferred to C1, C3, and C4 of the scan memories 27a, 27c, and 27d. The The data of the PIO unit 14b is also automatically transferred to D1, D2, and D4 of the scan memories 27a, 27b, and 27d by writing to D3 of the scan memory 27c.

  Therefore, the slave controller 11b can automatically capture the data of the PIO units 14a and 14b and the internal data of the master controller 11a by accessing the scan memory 27d of its own station without performing tracking transmission. .

The system block diagram for implement | achieving the data transmission method of the duplication controller concerning embodiment of this invention. Explanatory drawing of operation | movement by the data transmission method of the duplication controller concerning embodiment of this invention. The block diagram of a typical supervisory control system provided with the duplexed controller.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Controller, 12 ... Control LAN, 13 ... Human machine interface, 14 ... Process input / output unit, 15 ... Process input / output signal cable, 16 ... Controller, 17 ... CPU, 18 ... Tracking card, 19 ... Network interface, 20 ... Tracking cable, 21 ... Power supply, 22 ... CPU interface, 23 ... Digital I / O card, 24 ... Analog I / O card, 25 ... Pulse I / O card, 26 ... Contact I / O card, 27 ... Scan memory

Claims (2)

  A data transmission method for a duplex controller, wherein network scan transmission is used to equalize data between a master controller and a slave controller of the duplex controller. 2. The data transmission method of a duplex controller according to claim 1, wherein the scan transmission of the network is performed by using a bus access part between the CPU of the duplex controller and the process input / output unit.

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