JPH04367903A - Programmable controller dualizing system - Google Patents

Abstract

PURPOSE:To reduce the tracking time by performing the most efficient division of a tracking buffer. CONSTITUTION:In the programmable controller dualizing system in which tracking buffers 4, 5 are provided against a common controlled system, and also, two sets of programmable controllers 1, 2 of an operating system and a holding system having two scan periods of a high speed and a low speed are provided in parallel, and which tracks data to the holding system programmable controller 2 from the operating system programmable controller 1. by synchronizing with the scan periods of a high speed and a low speed, this system is provided with means 6, 7 for dividing the tracking buffers 4, 5 at the time of tracking, based on the tracking amount of a high speed and the tracking amount of a low speed.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention provides a programmable controller duplex system in which two programmable controllers equipped with a tracking buffer and having two scan periods, high speed and low speed, are provided in parallel for a common control object. The present invention relates to a system, and particularly to a programmable controller duplication system that implements the most efficient tracking buffer division to reduce tracking time.

0002

[Prior Art] Recently, in various industrial fields, programmable controller redundancy systems in which two programmable controllers, an active system and a standby system, are installed in parallel for a common control object have been widely used. ing. In this dual programmable controller system, each controller is usually equipped with a tracking buffer, and when each controller has two scan levels, high speed and low speed, the programmable controller system in the operating system is Data is written from the controller to the standby programmable controller (hereinafter referred to as tracking) so that the standby programmable controller can read it.

However, in a dual programmable controller system that has two tracking functions, high speed and low speed, it is necessary to set the high speed tracking buffer size and low speed tracking buffer size using an engineering tool. Whenever a task was added to each scan level or a slow scan task was moved to a high speed scan, the tracking amount had to be recalculated and reconfigured for each controller using the engineering tool.

Tracking becomes an overhead for an active programmable controller that performs continuous control, and there has recently been a strong demand to minimize the time required for tracking.

[0005]

[Problems to be Solved by the Invention] As described above, in conventional programmable controller duplication systems, tracking buffers are fixedly allocated to high speed and low speed, which results in inefficient tracking, that is, tracking time. The problem was that it became large.

It is an object of the present invention to provide an extremely reliable programmable system capable of implementing the most efficient tracking buffer partitioning to reduce tracking time.
The objective is to provide a dual controller system.

[0007]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides an active system and a standby system that are equipped with a tracking buffer and have two scan periods, high speed and low speed, for a common control object. 2 programmable
In a programmable controller duplication system in which controllers are arranged in parallel and data is tracked from the active programmable controller to the standby programmable controller in synchronization with high-speed and low-speed scan cycles, high-speed tracking amount and low-speed tracking can be achieved. The tracking buffer dividing means divides the tracking buffer at the time of tracking based on the amount.

In particular, the tracking buffer dividing means includes a means for calculating a high-speed tracking amount and a low-speed tracking amount, and based on the calculation result by this means and the tracking buffer size, the number of blocks required for the high-speed buffer, It consists of means for calculating the number of blocks required for a low-speed buffer and the number of blocks for the tracking buffer, and means for determining the tracking type from the calculation result of this means and varying the division of the tracking buffer based on the determination result. .

[0009]

[Operation] Therefore, in the dual programmable controller system of the present invention, the tracking buffer during tracking is divided according to the amount of high-speed tracking and the amount of low-speed tracking. By changing , changes in high-speed and low-speed tracking amount can be absorbed and optimal tracking can be performed.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a block diagram showing an example of the configuration of a dual programmable controller system according to the present invention. In FIG. 1, for a common control target (not shown), two programmable controllers 1 and 2, an active system and a standby system, each having two scanning cycles, high speed and low speed, are connected in parallel by a tracking cable 3. It is set up. Further, each programmable controller 1 and 2 includes tracking buffers 4 and 5 and tracking buffer dividing means 6 and 7. Then, data is tracked from the active programmable controller 1 to the standby programmable controller 2 in synchronization with the high-speed and low-speed scan cycles, so that the standby programmable controller 2 can read the data.

Here, each of the tracking buffers 4 and 5 is divided, for example, as shown in FIG. 2 (FIG. 2 shows the tracking buffer 5 of the standby programmable controller 2). In FIG. 2, the tracking buffer 5 is divided into four blocks B1 to B4, and blocks B1 and B2 are high-speed buffers,
Blocks B3 and B4 are used as low-speed buffers, respectively. The tracking buffer 5 is structured so that while the active system is writing data, the standby system can read blocks other than those being written.

On the other hand, each tracking buffer dividing means 6
, 7 is a means for calculating the high-speed tracking amount and the low-speed tracking amount, and the number of blocks required for the high-speed buffer, the number of blocks required for the low-speed buffer, and the tracking buffer based on the calculation result by this means and the tracking buffer size. a means for calculating the number of blocks, and determining the tracking type from the calculation result by this means,
and means for varying the division of the tracking buffer based on the determination result.

Next, a method of dividing the tracking buffer in the dual programmable controller system of this embodiment configured as described above will be explained with reference to FIGS. 3 to 10.
Explain using.

As shown in FIG. 3, in the tracking buffer dividing means 7 of the standby programmable controller 2, first, for example, at the start of tracking, the registration status of the task is searched by a program, so that the high-speed tracking amount HV, And a low-speed tracking amount LV is calculated.

Next, the calculated high-speed tracking amount HV, low-speed tracking amount LV, size BV of the tracking buffer 7, and minimum block unit UV are calculated.
From these, the number Hn of blocks required for a high-speed buffer, the number Ln of blocks required for a low-speed buffer, and the number Bn of blocks for the tracking buffer 7 are calculated using the following equations. Hn=HV/UV (add 1 if there is a remainder) Ln=LV
/UV (add 1 if there is a remainder) Bn=BV/UV

Next, it is determined from the calculated result that the tracking type is check, and the tracking buffer 7 is divided based on the check result. In other words, if the check results show only high-speed tracking,
The tracking buffer 7 is divided according to the processing flow shown in FIG. 4, when only low-speed tracking is required, according to the processing flow shown in FIG. 5, and when both types of tracking are required, according to the processing flow shown in FIG.

First, in FIG. 4, if the number of blocks Hn required for the high-speed buffer is larger than the number of blocks Bn of the tracking buffer 7 (Hn>Bn), the buffer is divided into two, each with the number of buffer blocks of Bn/2. use. Conversely, if the number Hn of blocks required for the high-speed buffer is smaller than the number Bn of blocks of the tracking buffer 7 (Hn<Bn), it is used as the number of buffer blocks of Bn without division.

In addition, in FIG. 5, when the number of blocks Ln required for the low-speed buffer is larger than the number of blocks Bn of the tracking buffer 7 (Ln>Bn), the buffer is divided into two, each with the number of buffer blocks of Bn/2. use. Conversely, if the number Ln of blocks required for the low-speed buffer is smaller than the number Bn of blocks of the tracking buffer 7 (Ln<Bn), it is used as the number of buffer blocks of Bn without division.

On the other hand, in FIG. 6, when the number of blocks Hn+Ln required for high-speed and low-speed buffers is smaller than the number of blocks Bn for the tracking buffer 7 (Hn+Ln≦B
n) is a two-part buffer division as shown in FIG. In addition, if the number of blocks Hn required for the high-speed buffer is less than half the number of blocks Bn of the tracking buffer 7 (H
n<Bn/2), the buffer is divided into three as shown in FIG. Furthermore, the number of blocks L required for slow buffering is
When n is less than half the number of blocks Bn of the tracking buffer 7 (Hn<Bn/2), the buffer is divided into three as shown in FIG. Furthermore, in cases other than the above, the buffer is divided into four as shown in FIG.

As described above, in this embodiment, two programmable systems, an active system and a standby system, each having tracking buffers 4 and 5 and having two scan periods, high speed and low speed, are used for a common control object. controller 1
and 2 in parallel to track data from the active programmable controller 1 to the standby programmable controller 2 in synchronization with high-speed and low-speed scan cycles, the high-speed tracking amount, and the low-speed tracking amount, and based on the calculated high-speed tracking amount, low-speed tracking amount, and tracking buffer size, the number of blocks required for the high-speed buffer,
Tracking buffer dividing means 6 and 7 are provided for calculating the number of blocks required for a low-speed buffer and the number of blocks for a tracking buffer, determining the tracking type from the calculation result, and varying the division of the tracking buffer based on the determination result. This is what I did.

Therefore, since the tracking buffers 4 and 5 during tracking are divided according to the amount of high-speed tracking and the amount of low-speed tracking, adding tasks and
Changes in high-speed and low-speed tracking can be absorbed by changing the state of the controller, such as deletion. This eliminates the need to divide the tracking buffer using an engineering tool every time the system is changed or expanded, as in the past, and it becomes possible to perform optimal tracking and reduce tracking time.

In the above embodiment, a case has been described in which the programmable controller 1 is an active system and the programmable controller 2 is a standby system, but the present invention is not limited to this. Even when the controller 1 is a standby system, the present invention can be similarly applied to obtain the same effects as described above.

[0024]

As explained above, according to the present invention, the tracking buffer dividing means for dividing the tracking buffer during tracking based on the high-speed tracking amount and the low-speed tracking amount is provided.
It is possible to provide an extremely reliable programmable controller duplication system that can implement the most efficient tracking buffer division and reduce tracking time.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a programmable controller duplication system according to the present invention.

FIG. 2 is a block diagram showing an example of access to the tracking buffer of the standby programmable controller in the same embodiment.

FIG. 3 is a flow diagram for explaining a tracking buffer dividing method in the same embodiment.

FIG. 4 is a flowchart for explaining a tracking buffer division method in the same embodiment.

FIG. 5 is a flowchart for explaining a tracking buffer division method in the same embodiment.

FIG. 6 is a flow diagram for explaining a tracking buffer dividing method in the same embodiment.

FIG. 7 is a diagram showing an example of buffer division types when there is high-speed and low-speed tracking in the same embodiment.

FIG. 8 is a diagram showing an example of buffer division types when there is high-speed and low-speed tracking in the same embodiment.

FIG. 9 is a diagram showing an example of buffer division types when there is high-speed and low-speed tracking in the same embodiment.

FIG. 10 is a diagram showing an example of buffer division types when there is high-speed and low-speed tracking in the same embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1... Active programmable controller, 2... Standby programmable controller, 3... Tracking cable, 4, 5... Tracking buffer, 6, 7... Tracking buffer dividing means, B1 to B4... Blocks.

Claims (2)

[Claims] [Claim 1] Two programmable systems, an active system and a standby system, each equipped with a tracking buffer and have two scan periods, high speed and low speed, for a common control object.
In a programmable controller duplex system in which controllers are provided in parallel and data is tracked from the active programmable controller to the standby programmable controller in synchronization with the high-speed and low-speed scan cycles, the high-speed tracking amount . A programmable controller dual system, comprising tracking buffer dividing means for dividing the tracking buffer during tracking based on the amount of low-speed tracking. 2. The tracking buffer dividing means includes means for calculating a high-speed tracking amount and a low-speed tracking amount, and based on the calculation result by this means and the tracking buffer size, the number of blocks required for the high-speed buffer and the number of blocks required for the low-speed buffer. means for calculating the number of blocks required for the buffer and the number of blocks for the tracking buffer, and determining the tracking type from the calculation result by the means;
2. The dual programmable controller system according to claim 1, further comprising means for varying division of the tracking buffer based on the determination result.