JP2557538B2 - Duplex system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a duplex system suitable for plant control and the like by a process computer.

(Prior Art) In the field of recent plant control, two process computers are provided for a common control target plant, one of them is operated as an online machine, and the other is operated as a standby machine to control reliability. A duplex system is adopted to improve the performance.

Conventionally, in such a redundant system, while monitoring the status of the partner system, the status of the partner system is changed from the standby status in response to the partner system being switched from the online status to the standby status for some reason. There was control to switch to the online state.

However, since the partner system status monitoring process and the self system status setting process are repeated in the same phase and the same cycle after the device is activated in both the partner system and the self system,
If you start both systems at the same time when starting up the system,
Since both systems are initially in a standby state, a so-called racing state in which the online state of both systems and the standby state of both systems are alternately repeated thereafter occurs, and the system cannot be normally started up.

Therefore, in this type of duplex system, as shown in FIG. 8, when starting up the system, an extra time lag T is required in order to avoid competition between the two.

(Problems to be Solved by the Invention) As described above, in the conventional duplex system of this type, in response to switching of the partner system from the online state to the standby state while monitoring the states of the partner system with each other. The control is performed to switch the own system from the standby state to the online state, and both systems have repeatedly fetched the other system's state and set the own system's state at the same phase and the same cycle after startup. If both are started at the same time, a so-called racing state occurs in which both the online state and the standby state are alternately repeated, the system cannot be started normally, and in order to avoid this, there must be a time difference between the startup of both systems. There was a problem.

The present invention has been made in view of the problems described in detail,
The purpose of the invention is to provide a duplex system that can smoothly start up the system.

[Structure of Invention]

(Means for Solving the Problem) The first invention of the present application is directed to a common control target
In a duplex system including two control devices, one of which operates as an online machine and the other of which operates as a standby machine, both control devices are placed under a common management device,
The management device gives a status instruction to each control device by 2-bit information, and each control device sets its own status according to the status instruction, and the 2-bit information is an online command. In the above case and in the case of the standby instruction, the bit sequence is reversed and transmitted from the management device to both control devices.

The second invention of this application is, on the side of each of the control devices,
The management device is informed of whether it is in the online state or the standby state, and the management device switches between the online states or the standby states when both control devices are notified at the same time. It is characterized in that it is determined to be abnormal, and the fact is notified to both control devices.

The third invention of this application is, on the side of each of the control devices,
The management device is notified of whether it is in the online state, the standby state, or the standby ready state, and the management device side notifies each of the state notifications when switching between the online device and the standby device. Based on the above, the switching procedure between the current online machine and the current standby machine is controlled.

(Operation) According to the first aspect of the invention as described above, one system has two
If bit information (1,0) is given, 2-bit information (0,1) is given to the other system, so 2-bit information (1,0) is an online command, and 2-bit information ( By arranging 0, 1) as the standby command, it is possible to reliably avoid giving the same status command to both systems.

According to the second invention of this application, when both the control devices notify the online state or the standby state at the same time, it is determined that this is a switching abnormality and the two control devices are notified of that. If a racing condition occurs, this can be avoided immediately.

According to the third invention of this application, since the management apparatus is notified of whether the own apparatus is in the online state, the standby state, or the standby ready state, sequence control is realized between the two control apparatuses based on this. By
It is possible to avoid the racing state described above.

(Embodiment) FIG. 1 is a block diagram showing an embodiment of a duplex system according to the present invention.

As shown in the figure, this duplex system includes two control devices, an A system control device 1A and a B system control device 1B, which are provided in parallel with each other with respect to a common control target (not shown).
It has.

Further, these two control devices 1A and 1B are integrally controlled by a common management device C.

Then, the management device C is adapted to give a status instruction to each of the control devices 1A and 1B by using 2-bit information (A, B).

2-bit information (A, B) sent from the management device C
Is transmitted to both control devices 1A and 1B by reversing the bit sequence. That is, the 2-bit information (A, B) sent from the management device C is transmitted as it is (A, B) to the A system control device 1A, whereas the B system control device 1B is transmitted.
Is transmitted as information (B, A).

Therefore, as shown in FIG.
When (0,1) is sent to give the system online instruction, the 2-bit information is transmitted as it is to the A system controller 1A as (0,1), while the B system controller 1B is transmitted. Is transmitted as (1,0) with the bit sequence reversed.

Similarly, when 2-bit information (1,0) is sent from the management device C to give the B-system online instruction, the 2-bit information is left as it is (1,0) and the A-system control device 1
While it is transmitted to A, it is transmitted to the B-system controller 1B as (0,1) with the bit arrangement reversed.

Furthermore, the switching abnormality is detected from the control device C by both control devices 1A and 1A.
When 2-bit information (1,1) is sent to B,
The 2-bit information is transmitted as (1,1) with the same content to both system control devices 1A and 1B.

On the other hand, in each of the A-system and B-system control devices 1A and 1B, a =
An online instruction is recognized when 0, b = 1, and a standby instruction is recognized when a = 1, b = 0.

In each of the A-system and B-system control devices 1A and 1B, the self-system instruction recognition process and the self-system state notification process are alternately repeated at regular intervals.

In the self-system status notification process, as shown in FIGS. 3 and 4, the online status, the standby status, and the standby ready status are each transmitted to the management apparatus C by 2-bit information.

That is, the contents of the 2-bit information (a1, a2) notified from the A-system control device 1A have (1,0) (0,0) (1,1), and are in the online state, the standby state, and the standby preparation, respectively. It shows a completed state.

Similarly, the contents of the 2-bit information (b1, b2) notified from the B-system control device 1B are (1,0), (0,0), (1,1)
With online status, standby status,
Shows the standby ready state.

Then, on the side of the management device C, as shown in FIG. 6, status notifications are fetched from the A system and the B system at appropriate timings (steps 601, 602), and according to the agreement described in FIGS. 3 and 4, ( (Steps 603 to 608), A system online, A system standby, A system standby ready, B system online, B standby, B system standby ready are respectively recognized (steps 609 to 614).

Therefore, when a so-called racing state occurs in which the control devices 1A and 1B of the A system and B system are both in the online state and in the standby state, as shown in FIG. 5, a state monitoring process (step 501 6), the switching abnormality is judged based on the recognition result (steps 502, 503), and immediately a = b = for both control devices 1A, 1B.
1 (switching abnormality) can be sent (steps 504, 505) to notify each control device 1A, 1B that an operation abnormality has occurred (steps 504, 505).

Next, assuming that the A-system control unit 1A is online and the B-system control unit 1B is in the standby state, from this state, the A-system control unit 1A is in the standby state and the B-system control unit is in the online state. The sequence control for switching to will be described with reference to the flowchart of FIG.

As shown in the figure, when a B-system online instruction is issued from the management device C (step 701), the instruction is B
It is transmitted to the system controller 1B as a B system online instruction, and to the A system controller 1A as an A system standby instruction.

Then, the A-system control device 1A waits for the arrival of the instruction (step 704YES) and notifies the management device C of the standby preparation completion (step 705).

On the other hand, the B-system control device 1B waits for the instruction (step 708YES) and waits for the A-system standby preparation completion notification from the A-system control device 1A (step 70).
9).

In this state, in the management device C, the A system control device 1A
Standby ready notification from B system controller 1B
Relay processing is performed for delivery to (step 702).

In this way, when the standby preparation completion notification from the A system control device 1A is transmitted to the B system control device 1B (step 709 YES), the B system control device 1B immediately switches to the online state in response to this. Do (step 710),
At the same time, the system B online completion is notified to the management device C (step 711).

On the other hand, on the side of the A system control device 1A, after notifying the management device C of the standby preparation completion (step 705), the system waits for the B system online completion notification from the B system control device (step 705). 706).

At this time, the management apparatus C carries out a relay process for passing the B system online completion notification from the B system control apparatus to the A system control apparatus (step 703).

In this way, the B system controller 1B to the A system controller 1A
B system online completion notification to
706YES), and in response to this, the A system control device 1A switches to the standby state (step 707).

According to the above processing, even if both online states and both standby states occur in the transition period from the online state to the standby state and from the standby state to the online state, the management apparatus C follows the determined order in the A system, the B system, and the B system. Since the switching between the system control devices 1A and 1B is appropriately controlled, the so-called racing state, which has been a problem in the past, does not occur.

Further, although the above description has been made in the case where the online machine and the standby machine are switched after the control device starts to operate, the same is true when the system is started up. Under the control of the management device B, the A system and the B system are controlled. Each control device 1A, 1B can smoothly transition to a normal operating state.

[Effects of the Invention] As is clear from the above description, according to the first invention of this application, the 2-bit information transmitted from the management device is transmitted to both control devices by reversing the bit sequence. Therefore, it is possible to avoid giving the same instruction to both control devices by mistake.

Further, according to the second invention of this application, when an abnormal state such as both online and both standby occurs between both control devices, it is possible to make each control device immediately recognize this.

Further, according to the third invention of this application, it is possible to smoothly switch between the online machine and the standby machine at the time of system startup, switching during operation, and the like.

[Brief description of drawings]

FIG. 1 is a block diagram schematically showing the overall configuration of a duplex system according to the present invention, FIG. 2 is an explanatory diagram showing the contents of 2-bit information sent from a management device, and FIG. 3 is an A system control device. 2 is an explanatory view showing the contents of 2-bit information notified from FIG. 4, FIG. 4 is an explanatory view showing the contents of 2-bit information notified from the B-system control device, and FIG. 5 is both online states,
FIG. 6 is a flowchart showing the process of the management device when both standby states occur, FIG. 6 is a flowchart showing the details of the state monitoring process in FIG. 5, and FIG. 7 is both control devices at the time of switching between the online state and the standby state. And a flowchart showing the operation of the management apparatus, 8
The figure is a block diagram schematically showing the operation of the conventional apparatus. 1A ... A system control device 1B ... B system control device C ... Management device A, B ... 2-bit information for status indication a1, a2 ... 2-bit information notified from A system control device b1 , b2 ... 2-bit information notified from the B system controller

Claims (3)

(57) [Claims] 1. A duplex system comprising two control devices for a common control target, one of which is operated as an online machine and the other of which is operated as a standby machine. In addition to being placed under the device, the management device gives a status instruction to each control device by 2-bit information, and each control device side sets its own status in accordance with the status instruction, and Information is transmitted to the both control devices from the management device and the opposite bit in the case of the online command and the standby command. 2. Each of the control devices notifies the management device whether it is in an online state or a standby state, and on the management device side, both control devices simultaneously enter an online state. 2. The duplex system according to claim 1, wherein when the standby state is notified, it is determined that this is a switching abnormality and both control devices are notified of that. 3. The control device side notifies the management device whether it is in an online state, a standby state, or a standby ready state, and the management device side determines that the online device is 2. The duplex system according to claim 1, wherein, when the standby machine is switched, the switching procedure between the current online machine and the current standby machine is controlled based on the status notifications.