JP2007304921A - Cpu duplex system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a CPU duplex system having a CPU duplex switching unit capable of easily constructing the CPU duplex system even when the CPU modules are inexpensive and various. <P>SOLUTION: A system has two CPU modules 1 and alternately changes the states of control/standby of two CPU modules has one CPU duplex switching unit 5 for two CPU modules. The CPU duplex switching unit comprises a CPU state input circuit 2 for inputting abnormal states of two CPU modules, an abnormality diagnostic circuit 3 for detecting abnormality, and a duplex system switching circuit 4 for determining the switch between the control state and standby state of two CPU modules. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a CPU duplication system used in a control apparatus such as a plant that requires high reliability.

  Generally, in a control device such as an important blunt that requires high reliability, it is required to have double CPU modules that perform the control calculation.

  2 and 3 are configuration diagrams showing an example of a conventional CPU duplex system (see, for example, Patent Document 1). In the CPU duplex system shown in FIG. 2, the CPU module 21 is equipped with an abnormality diagnosis circuit 23 and a dual system switching circuit 24. Each CPU module 21 monitors its own (own system) abnormality by its own abnormality diagnosis circuit 23, and normal / abnormal of the other party (other system) via the dual system switching circuit 24, And control / standby status is monitored. Here, when an abnormality occurs in the active CPU module 21 or when other control / standby switching conditions are satisfied, the control authority is given to the standby CPU module 21 by both the dual system switching circuits 24. Is transferred, and the active system and the standby system are switched. Reference numeral 29 denotes a signal line for connecting the two dual system switching circuits 24 and outputting a control / standby state command signal.

  In the CPU duplication system shown in FIG. 3, the CPU status signal is transmitted by connecting the two CPU modules 31, the RAS module 32 corresponding to them, and the CPU module 31 and the RAS module 32. It comprises a data bus 35 and a signal line 39 for connecting the two RAS modules 32 and transmitting a control / standby state signal. On the RAS module 32, an abnormality diagnosis of the CPU module 31 paired therewith is made. An abnormality diagnosis circuit 33 and a dual system switching circuit 34 are mounted. The abnormality diagnosis circuit 33 of the RAS module 32 is provided with an abnormality monitoring timer 38 as a part thereof. In addition, the RAS module 32 has a priority system selection function for setting the control / standby state at the start-up for the dual system switching circuit 34 and a manual selection function for manually switching the control / standby state. A provided switch 40 is provided.

  Conventionally, by providing such a CPU duplication system, a risk avoidance at the time of trouble in the CPU module has been attempted.

JP 2001-60160 A (FIGS. 1 and 5)

  In FIG. 2, the conventional CPU duplex system described above needs to have an abnormality diagnosis circuit 23 and a dual system switching circuit 24 having a sufficient function for monitoring an abnormality on the CPU module 21, and such a CPU is required. In order to build a duplex system, it is necessary to use a dedicated CPU module for duplex or develop a CPU module having an equivalent function. Also, the CPU redundant system of FIG. 3 can be easily applied to general-purpose CPU modules having the same bus specifications, but when applied to CPU modules having different path specifications, a new RAS module 32 needs to be developed. . Therefore, the conventional system configuration has problems in terms of cost and changing the model of the CPU module.

  The present invention has been made to solve the above problems, and provides a CPU duplication system including a CPU duplication switching unit that can easily construct a CPU duplication system even with a wide variety of CPU modules at low cost. To do.

  In the dual CPU system according to the present invention, there are two CPU modules, and the control / standby states of the two CPU modules are alternately changed as necessary. The CPU duplication switching unit has a CPU duplication switching unit that switches between a CPU status input circuit that inputs an abnormal state of two CPU modules, an abnormality diagnosis circuit that detects an abnormality, and a control / standby state of the two CPU modules. And a dual system switching circuit for making a decision.

  According to the present invention, the CPU redundant detection unit and the dual system switching function are provided in a separate CPU redundant switching unit, so that no special switching processing is required for the CPU module, and a CPU redundant system is constructed at low cost. it can. In addition, by mounting a plurality of CPU module status signal inputs in the CPU status input circuit of the CPU duplex switching unit so as to meet the output specifications of various CPU modules, the CPU module can be applied to various CPU modules having different output specifications.

FIG. 1 is a system configuration diagram showing a dual CPU system according to Embodiment 1 of the present invention.
The CPU duplex system of the present invention shown in the figure includes two CPU modules 1, one CPU duplex switching unit 5, a signal line 7 for transmitting a CPU status signal from the CPU module 1, and a CPU module based on the CPU duplex switching unit 5. 1 and a signal line 9 for transmitting a control / standby state command.

  Here, the CPU module 1 is a general-purpose module not equipped with an abnormality diagnosis circuit, a dual system switching circuit, or the like. On the other hand, the CPU duplex switching unit 5 was developed for the CPU duplex system of the present invention, and is a CPU duplex switching unit having an abnormality diagnosis function, a dual system switching function, a CPU signal input function, and the like.

  On the CPU duplex switching unit 5, two CPU status input circuits 2 that can input CPU status signals output from the two CPU modules 1 in accordance with the output specifications, and two that diagnose each of the two CPU modules 1 are diagnosed. The abnormality diagnosis circuit 3 and one dual system switching circuit 4 for determining switching between the control / standby states of the two CPU modules 1 are mounted. An abnormality monitoring timer 8 is provided as a part of the abnormality diagnosis circuit 3 of the CPU duplex switching unit 5. Further, the CPU duplex switching unit 5 has a priority system selection function for setting the control / standby state at the start-up for the dual system switch circuit 4 and a manual selection for manually switching the control / standby state. A switch 10 having a function is provided.

  Next, functions and operations of the dual CPU switching unit of the present invention will be described below. First, the CPU module 1 outputs a CPU status signal to the CPU duplex switching unit 5 through the signal line 7 at regular intervals. This signal enables digital (DO) output, LAN communication output, and serial communication output according to various CPU modules. The CPU duplex switching unit 5 receives the CPU status signal from the CPU module 1 by the CPU status input circuit 2, and the CPU status input circuit 2 accesses the abnormality diagnosis circuit 3 every time it is received.

  The abnormality diagnosis circuit 3 clears the abnormality monitoring timer 8 by access from the CPU state input circuit 2. As a result, the normal / abnormal state of the CPU module 1 is grasped, and when the abnormality monitoring timer 8 times out, the CPU module 1 is determined to be abnormal, and the dual system switching circuit 4 controls / waits to the CPU module 1. A status command is output and control switches from the local system to another system.

  At the time of start-up and manual switching, a control / standby state command signal is similarly output from the dual system switching circuit 4 according to an instruction from the switch 10 to determine the control / standby state.

  As described above, according to the present invention, the duplex switching dedicated unit is provided outside the CPU module, and various interfaces with the CPU module are mounted. Therefore, it is not necessary to create a duplex switching logic and can be applied to a wide variety of CPU modules. Therefore, it is possible to construct a CPU duplex system at a low cost.

BRIEF DESCRIPTION OF THE DRAWINGS It is a system block diagram which shows the CPU duplication system in Embodiment 1 of this invention. It is a system block diagram which shows an example of the conventional CPU duplication system. It is a system block diagram which shows the other example of the conventional CPU duplication system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 CPU module 2 CPU status input circuit 3 Abnormality diagnosis circuit 4 Duplex system switching circuit 5 CPU duplication switching unit 7 Signal line (CPU status signal)
8 Abnormality monitoring timer 9 Signal line (Control / standby state command signal)
10 switch

Claims (2)

In a CPU duplex system having two CPU modules and alternately changing the control / standby state in the two CPU modules as necessary,
One CPU duplication switching unit for the two CPU modules;
The dual CPU switching unit is a CPU state input circuit that inputs an abnormal state of the two CPU modules, an abnormal diagnosis circuit that detects an abnormality, and a dual determination that switches between control / standby states of the two CPU modules. A dual CPU system comprising a system switching circuit.   2. The CPU duplex system according to claim 1, wherein the CPU status input circuit has a plurality of input means such as digital, LAN communication, serial communication and the like.

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