JP3090816B2 - Redundant control system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control system which collects information from a terminal by a control device and performs predetermined arithmetic processing. The present invention relates to a redundant control system in which an input / output device that relays information transmission between the control device and the communication device is duplicated.

[0002]

2. Description of the Related Art For example, in a process control system for controlling a plant in a factory, the operating state (process data) of each device constituting the plant is detected by each sensor attached to each device, and the detected state is sent to a central monitoring and control room. The data is transmitted to the control device composed of the installed computer. in this case,
Process data detected by each sensor is once normalized by an input / output device, A / D converted, converted into a format that can be understood by the control device, and then input to the control device.

In order to improve the reliability of the entire control system, the two input / output devices described above are connected in parallel, and usually, the input / output devices specified on the operation side are used.
When an abnormality occurs in the active-side input / output device, a redundant control system that designates the standby-side device as the active-side device is employed.

[0004] Such a redundant control system is configured, for example, as shown in FIG. The sensor 1 attached to each device constituting the plant is called a "smart sensor", and a small microprocessor is built in the sensor 1, so that it not only detects a physical quantity but also
Change measurement items according to external control commands,
It has a function to change the measurement range.

[0005] Smart transmission devices 3 a and 3 b as input / output devices having the same configuration are connected to the sensor 1 via a signal line 2. The smart transmission devices 3a and 3b are connected to a control device 5 via a transmission line 4.

[0006] The control device 5 composed of an information processing device such as a computer is provided with the pair of smart transmission devices 3a and 3a.
One of b is designated as the active transmitter, and the other is designated as the standby transmitter.

Each of the smart transmission devices 3a and 3b is configured, for example, as shown in FIG. The smart transmission devices 3a and 3b are constituted by a kind of computer. That is, a ROM 8 for storing fixed data such as a program, a RAM 9 for temporarily storing various variable data such as data received from the sensor 1 via a bus line 7 to a CPU 6 for executing various information processing, a transmission path 4 Control unit-side transmission / reception unit 1 for transmitting information to and from control device 5 via
0, a sensor transmitting / receiving unit 11 for transmitting information to and from the sensor 1 via the signal line 2 is connected.

In the redundant control system having such a configuration, the control device 5 sends a data read request to the sensor 1 via the transmission line 4 to, for example, the smart transmission device 3a designated as the active side. The read request input to the smart transmission device 3a is received by the controller-side transmitting / receiving unit 10. When the CPU 6 of the smart transmission device 3 a receives the read request via the control operation side transmission / reception unit 10, it creates a read request text according to the program in the ROM 8 and sends the read request text to the sensor 1 via the sensor side transmission / reception unit 11 and the signal line 2. Send to

The sensor 1 that has received the read request text measures data corresponding to the read request, incorporates this data into the response text, and transmits it to the requesting smart transmission device 3a.

The CPU 6 of the smart transmission device 3a receiving the response text from the sensor 1 at the sensor-side transmitting / receiving section 11
Determines whether the data included in the response text is normal or abnormal, and if the data is normal, returns the data to the control device 5 via the control device-side transmitting / receiving unit 10 and the transmission path 4.

The controller 5 not only collects data from the sensor 1 but also sends various control commands to the sensor 1 as necessary, such as a command to change a measurement item and a command to change a measurement range. It is also possible.

When an abnormality occurs in the active smart transmission device 3a and the operation becomes inoperable, the control device 5 designates the standby smart transmission device 3b as the active side, and designates the active smart transmission device 3b in which the abnormality has occurred. The smart transmission device 3b is designated as the standby side. Therefore, even if an abnormality occurs in either one, control device 5 can normally and continuously collect data from sensor 1.

In addition, for example, at the time of inspection and maintenance (maintenance) instead of occurrence of an abnormality, the operating smart transmission equipment 3a is switched to the standby side as necessary, and necessary inspection and maintenance (maintenance) is performed.

[0014]

However, the dual control system shown in FIGS. 7 and 8 has the following problems to be improved. In such a redundant control system, in order to improve the reliability of data collection from the sensor 1, each smart transmission device 3a, 3b
Performs self-diagnosis at regular intervals. When an abnormality is detected, the controller 5 is notified at that time. This self-diagnosis is performed both during the period when each of the smart transmission devices 3a and 3b is designated as the active side and during the period when each of the smart transmission devices 3a and 3b is designated as the standby side.

This self-diagnosis is performed by the smart transmission equipment 3a,
CPU 6 shown in FIG.
9. Control device side transmission / reception unit 10 and sensor side transmission / reception unit 11
It is actually operated to check whether or not each operation in is normal.

For example, in the smart transmission device 3a designated as the operation side, when the self-diagnosis of the sensor side transmission / reception section 11 is performed, the actual read request requested from the control device 5 is incorporated into the text to actually execute the self-diagnosis. To the sensor 1 to check whether or not the response text from the sensor 1 is normal.

However, since the smart transmission device 3b designated as the standby side does not transmit information to the sensor 1 in principle, the smart transmission device 3b on the standby side cannot perform self-diagnosis on the sensor transmitting / receiving section 11. Occurs.

It is possible to create a test read request text and drive the sensor-side transmitting / receiving unit 11 only for the purpose of self-diagnosis. However, when the test text is transmitted to the sensor 1 via the signal line 2, there is a concern that the text on the signal line 2 may compete with the regular read request text transmitted by the active smart transmission device 3 a. In this case, one of the texts is kept waiting, and in some cases, there is a concern that the regular read request text is kept waiting.

Also, on the sensor 1 side, if two texts are input at the same time or with a short time interval, there is a concern that the processing response to the normal read request text may be delayed in some cases.

As described above, the smart transmission device 3 on the standby side
If the text for test is sent from b to the sensor 1, there is a concern that the legitimate processing of the active smart transmission device 3a may be adversely affected.

Therefore, in the conventional redundant control system, as a practical problem, the self-diagnosis of the sensor-side transmitting / receiving unit 11 in the smart transmission device 3b on the standby side has not been executed.

The present invention has been made in view of such circumstances, and the input / output device on the operating side performs the execution timing of the information transmission for diagnosis performed by the input / output device on the standby side with the terminal. By setting in consideration of the timing of legitimate information transmission, it is possible to perform a complete self-diagnosis of the standby side input / output device without affecting the regular information transmission performed by the active side input / output device at all, It is an object of the present invention to provide a redundant control system that can further improve the reliability of the entire system.

[0023]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a control device for collecting information from a terminal and performing a predetermined arithmetic processing, and a parallel connection between the control device and the terminal. With a pair of inserted input / output devices, the input / output device designated as the active side by the control device of the pair of input / output devices relays information transmission between the terminal device and the control device, In a redundant control system in which the input / output device designated as the standby side maintains the standby state, the information between the input / output device designated as the active side and the terminal for the input / output device designated as the standby side Transmission monitoring means for monitoring the state of transmission, and transmission self-diagnosis means for transmitting information for self-diagnosis between the terminal and the terminal after completion of information transmission between the terminal and the operating side input / output device are added. doing.

Further, in the redundant control system according to another invention, after the information transmission between the input / output device designated by the operating side and the terminal being executed by itself is completed, the designated input / output device is designated by the standby side. A standby-side transmission diagnostic unit for transmitting information for diagnosing the standby-side input / output device to / from the input / output device is added.

Further, in another invention, a control device for collecting information from a plurality of terminals at a fixed period and performing predetermined arithmetic processing, and a control device and a terminal interposed in parallel are provided between the control device and each terminal. A pair of input / output devices, of which the input / output device designated as the active side by the control device relays information transmission between each terminal and the control device, and the standby side In a redundant control system in which the input / output device designated as `` maintains the standby state, '' when the input / output device designated as the active side has finished transmitting information to / from each terminal to the control device, Virtual switching means for virtually switching between the operating side and the standby side only during one cycle of the above is added. Further, for the standby input / output device virtually designated as the active side,
Transmission self-diagnosis means for executing self-diagnosis information transmission with each terminal during the next one cycle is added.

[0026]

In the redundant control system configured as described above, the input / output device designated as the standby side monitors the normal information transmission executed between the active input / output device and the terminal, and When the information transmission is completed, information transmission for self-diagnosis is executed between itself and the terminal.

Therefore, the information transmission for self-diagnosis does not compete with the regular information transmission performed by the operating side input / output device. Therefore, a complete self-diagnosis of the standby-side input / output device can be performed without affecting the normal information transmission performed by the active-side input / output device at all.

In another aspect of the invention, diagnosis of information transmission to the standby input / output device is executed by the active input / output device, not by the standby input / output device. Therefore, there is no conflict between the normal information transmission performed by the operating side to the terminal device and the diagnostic information transmission performed by the operating side to the standby side.

Further, in another invention, when collecting information from a plurality of terminals at regular intervals, when one cycle in which the control device collects information from all the terminals in one cycle ends, the next one is completed. The working side and the standby side are virtually switched only during the period.

The standby-side I / O device virtually designated as the active side performs self-diagnosis at the timing when the active-side I / O device virtually designated as the standby side is transmitting normal information. Information can be transmitted to and from a terminal. Therefore, the control device collects information every other cycle, but each terminal responds to the regular information transmission and the self-diagnosis information transmission every cycle.

[0031]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of a redundant control system according to the embodiment. The same parts as those of the conventional redundant control system shown in FIG. 7 are denoted by the same reference numerals. Therefore, the detailed description of the overlapping part is omitted.

In the system of this embodiment, the sensors 1 as three terminals are connected to the smart transmission devices 13a and 13b as input / output devices via a common signal line 2.
a, 1b, and 1c are commonly connected. Therefore,
Each of the smart transmission devices 13a and 13b can independently execute information transmission with each of the sensors 1a to 1c. Further, the smart transmission devices 13a and 13b are also connected to each other via the common signal line 2.

Each of the smart transmission devices 13a, 13b
Is composed of a CPU 6, a ROM 8, a RAM 9, a control device-side transmission / reception unit 10, a sensor-side transmission / reception unit 11, and the like, similarly to the smart transmission devices 3a and 3b shown in FIG. Further, it is connected to the control device 5 via the transmission line 4.

The control device 5 of the redundant control system having the above-described configuration is configured to control any one of the smart transmission devices 13.
a and 13b are designated as active sides, and the other smart transmission devices 13b and 13a are designated as standby sides. In this embodiment, it is assumed that the smart transmission device 13a is designated as the active side and the smart transmission device 13b is designated as the standby side.

The collected in this state, the sensor 1a controller 5 at a predetermined period T _0, 1b, data from 1c. More specifically, as shown in FIG. 2 (a), 1 cycle each period T ₀ in the 3 equal portions T _1. Each sensor 1 in T ₂ , T ₃
A read request for a, 1b, and 1c is sent to the active smart transmission device 13a via the transmission path 4.

Each sensor 1a, 1b, 1 from the controller 5
On the other hand, the active-side smart transmission device 13a that has received the read request with respect to each of the periods T ₁ . T ₂ , T
_The data is transmitted to each of the sensors 1a, 1b, and 1c within ₃ . Each sensor 1a, 1b, 1c has the same T ₁ . The data is measured within T ₂ , T _3, and the measured data is incorporated into the response text and returned to the smart transmission device 13a as the transmission source.

Therefore, the smart transmission device 1 on the operating side
2 (a) between the sensor 3a and each of the sensors 1a, 1b, 1c.
The regular information transmissions A ₁ , A ₂ and A ₃ are executed at the timings shown in FIG.

The active smart transmission device 13a, which has received the response text from each of the sensors 1a, 1b, 1c, transmits the data to the control device 5 via the transmission line 4. FIG.
(A) each sensor 1a at the timing shown in, 1b, normal information transmission A ₁ between 1c, A _2, smart transmission equipment operating side running A ₃ 13a is incorporated in the self-device The operation of the CPU 6, the RAM 8, the RAM 9, the control operation side transmission / reception unit 10 and the sensor side transmission / reception unit 11 is self-diagnosed according to a self-diagnosis program, and is transmitted to the control device 5 via the transmission line 4 only when an abnormality is detected.

Similarly, the smart transmission device 13b on the standby side
Also, CPU6, RAM8, RAM built into own equipment
9. Control operation side transmission / reception section 10 and sensor side transmission / reception section 11
Is self-diagnosed according to the self-diagnosis program, and is transmitted to the control device 5 via the transmission line 4 only when an abnormality is detected.

Next, a self-diagnosis procedure for the sensor-side transmitting / receiving unit 11 in the smart transmission device 13b on the standby side will be described. That is, the smart transmission device 13b on the standby side
Monitors the timing of the normal information transmissions A ₁ , A ₂ , and A ₃ executed by the active-side smart transmission device 13 a by the sensor-side transmission / reception unit 11 via the common signal line 2.

Then, as shown in FIG. 2A, the standby-side smart transmission device 13b transmits the regular information transmissions A ₁ , A ₂ , A ₃ executed by the active-side smart transmission device 13a.
At the end of each of the periods T ₁ , T ₂ , and T ₃ , information transmission B for self-diagnosis with the sensors 1a, 1b, and 1c.
_1, it executes the B _2, B _3.

Specifically, the smart transmission device 1 on the standby side
The test text is transmitted from 3b to each sensor 1a, 1b, 1c via the signal line 2, and each sensor 1a, 1b,
Each response text from 1c is received, and it is determined whether each response text is normal.

FIG. 2B shows that the control unit 5 controls the sensors 1a,
Change the order of collecting each data from 1b, 1c,
When only the specific sensor 1a collects data in a short cycle, the information transmission A ₁ , A ₂ , A ₃ . A ₄ ... And the self-diagnosis information transmissions B ₁ , B ₂ , B ₃ . B ₄ ... illustrates each timing.

As shown in the figure, regardless of the timing at which the active smart transmission device 13a executes normal information transmission, each information transmission for self-diagnosis executed by the standby smart transmission device 13b is performed. Contention with each legitimate information transmission is prevented.

In the thus configured redundant control system, the information transmission B ₁ , B ₂ , B ₃ for self-diagnosis performed by the smart transmission device 13b on the standby side with each of the sensors 1a, 1b, 1z is , Smart transmission device 13a on the operating side
Does not compete on the signal line 2 with the regular information transmissions A ₁ , A ₂ , A ₃ performed between the sensors 1a, 1b, 1c. Therefore, it does not affect the normal information transmissions A ₁ , A ₂ , and A ₃ performed by the active smart transmission device 13a.

That is, the smart transmission device 13 on the operating side
without affecting the legitimate information transmission performed by a.
Complete self-diagnosis of the smart transmission device 13b on the standby side can be performed. Therefore, the reliability of the entire redundant control system can be further improved.

FIG. 3 is a block diagram showing a schematic configuration of a duplex control system according to another embodiment of the present invention. FIG.
The same reference numerals are given to the same parts as those of the embodiment. Therefore, the detailed description of the overlapping part is omitted.

In the system of this embodiment, as shown in FIG. 4, the smart transmission device 14a
The normal information transmission A at a predetermined period T ₄ between the sensor 1
By running _1, A _2, A _3, ... of the sensor 1
Collect data from

Further, the smart transmission device 1 on the operating side
4a, for example, every time the transmission of a predetermined number N (= 3) of information is completed, the smart transmission device 1 on the standby side via the signal line 2.
The information transmission for diagnosis B ₁ , B ₂ . In this case, the standby-side smart transmission device 14b returns a response text to the diagnostic text received from the active-side smart transmission device 14a to the active-side smart transmission device 14a.

The active-side smart transmission device 14a determines whether the sensor-side transmission / reception unit 11 of the standby-side smart transmission device 14b is normal or abnormal from the response text. When an abnormality is detected, the control unit 5 is notified of the occurrence of an abnormality on the standby side.

In the redundant control system configured as described above, the sensor-side transmitting / receiving section 11 of the smart transmission device 14b on the standby side is diagnosed by the smart transmission device 14a on the active side. Therefore, regular information transmission A ₁ , A
_2, A _3, ... so that no conflict with information transmission B _1, B ₂ for diagnosis, it is possible to obtain substantially the same effects as in Example system shown in FIG.

FIG. 5 is a block diagram showing a schematic configuration of a redundant control system according to still another embodiment of the present invention. The same parts as those in the embodiment of FIG. 1 are denoted by the same reference numerals. Therefore, the detailed description of the overlapping part is omitted.

The control device 16 in this embodiment system
Usually designates one smart transmission device 15a as the active side and the other smart transmission device 15b as the standby side.

In addition, the control device 16 sends the regular information transmissions A ₁ , A ₂ , and A _{1 to} all the sensors 1a, 1b, 1c.
Whenever the required time over a certain period T ₀ set in the course of A _3, switching the operating side and the standby side virtually. For example, in FIG. 6, the period of time t ₁ ~t ₂ is a smart transmission equipment 15a is operational side, the smart transmission equipment 15b
Is the standby side. Then, in the period of the next time t ₂ ~t _3, stand-by side and operating side virtually off switched.

T, at which the active side and the standby side are virtually switched
In a period of ₂ ~t _3, the smart transmission equipment 15b is virtually becomes operational side, the smart transmission equipment 15a is virtually stand-by side.

In this period t ₂ -t ₃ ,
The original active-side smart transmission device 15a virtually designated as the standby side does not execute regular information transmission with the sensors 1a, 1b, and 1c. On the other hand, in this period t ₂ ~t _3, the smart transmission equipment 15b of the standby side specified for virtually operating side, smart transmission equipment 15a of the given virtually the standby side operating side legitimate inherent at the timing that implement information transmission, information transmission B ₁ for self-diagnosis with each sensor _{1a, 1b, 1c, B 2} . To run the B _3.

Therefore, the virtual switching period t _{2 to} t ₃
, The control device 16 controls the sensors 1a, 1b, 1c
Do not receive data from. Then, during this period t _{2 to} t
_When one cycle T _{0 of 3} elapses, the control device 16 returns the virtual switching to the original state. Then, the control device 16 receives data from each of the sensors 1a, 1b, 1c via the smart transmission device 15a.

Therefore, the control device collects data from the sensors 1a, 1b, 1c every other cycle, but the sensors 1a, 1b, 1c transmit regular information transmissions A _{1 to} A ₁ every cycle. ₃ and information transmission B _{1 to} B ₃ for self-diagnosis
Respond to each text.

Therefore, at the same time, the normal information transmission A _{1 to} A ₃
And the information transmissions B _{1 to} B ₃ for self-diagnosis are not executed, so that substantially the same effects as those of the systems of the above-described embodiments can be obtained. Further, in the system of this embodiment, the transmission processing load on the sensors 1a, 1b, 1c does not particularly increase.

[0060]

As described above, in the redundant control system according to the present invention, the active input / output device performs the execution timing of the information transmission for diagnosis performed by the standby input / output device with the terminal. The setting is made in consideration of the legitimate information transmission timing. Therefore, a complete self-diagnosis of the standby-side input / output device can be performed without affecting the normal information transmission performed by the active-side input / output device, and the reliability of the entire system can be further improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of a redundant control system according to an embodiment of the present invention.

FIG. 2 is a time chart showing the operation of the system of the embodiment.

FIG. 3 is a block diagram showing a schematic configuration of a redundant control system according to another embodiment of the present invention.

FIG. 4 is a time chart showing the operation of the system of the embodiment.

FIG. 5 is a block diagram showing a schematic configuration of a redundant control system according to still another embodiment of the present invention.

FIG. 6 is a time chart showing the operation of the system of the embodiment.

FIG. 7 is a block diagram showing a schematic configuration of a conventional duplex control system.

FIG. 8 is a block diagram showing a schematic configuration of a general smart transmission device.

[Explanation of symbols]

1,1a. 1b, 1c sensor, 2 signal line, 4 transmission line, 5, 16 control device, 6 CPU, 8 ROM, 9
… RAM, 10… Control device side transmitting / receiving section, 11… Sensor side transmitting / receiving section, 13a, 13b, 14a, 14b, 15a,
15b: Smart transmission equipment.

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) H04Q 9/00-9/16 G05B 15/02 H04L 1/22 H04L 29/14

Claims (3)

(57) [Claims] 1. A control device for collecting information from a terminal and performing a predetermined arithmetic processing, and a pair of input / output devices interposed in parallel between the control device and the terminal. Of the pair of input / output devices, the input / output device designated as active by the control device relays information transmission between the terminal and the control device, and the input / output device designated as standby is In a redundant control system that maintains a standby state, the input / output device specified as the standby side is a transmission monitoring unit that monitors a state of information transmission between the input / output device specified as the active side and the terminal. And transmission self-diagnosis means for transmitting information for self-diagnosis between the terminal and the terminal after the information transmission between the terminal and the active side input / output device is completed. system. 2. A control device for collecting information from a terminal and performing a predetermined arithmetic processing, and a pair of input / output devices interposed in parallel between the control device and the terminal. Of the pair of input / output devices, the input / output device designated as active by the control device relays information transmission between the terminal and the control device, and the input / output device designated as standby is In a redundant control system that maintains a standby state, the input / output device designated as the active side is the input / output device designated as the standby side after information transmission to / from the terminal being executed by itself is completed. And a standby transmission diagnostic unit for transmitting information for diagnosing a standby input / output device to and from the redundant control system. 3. A control device that collects information from a plurality of terminals at a constant period and performs a predetermined arithmetic processing, and a pair of input / output devices inserted in parallel between the control device and each of the terminals. Device, the input / output device designated as the active side by the control device of the pair of input / output devices relays information transmission between the terminals and the control device, and the standby side In a redundant control system in which a designated input / output device maintains a standby state, the control device performs the following when the designated input / output device terminates information transmission with each of the terminals. Virtual switching means for virtually switching between the active side and the standby side only for one cycle; and the standby-side input / output device virtually designated as the active side,
A duplex control system comprising transmission self-diagnosis means for executing information transmission for self-diagnosis with each of the terminals during the next cycle.