JPH03160501A - Distributed control system - Google Patents

Abstract

PURPOSE:To eliminate necessity for especially set up a station equipped with a backup function by mutually backing up respective operator stations by controlling a table for the unit of a job. CONSTITUTION:When detecting the fault (down) of an operator station 11 under executing a job 1, the operator station detecting down activates the backup station of the job 1 according to the table of an internal part. In such a case, the executing station is the operator station 11 and the backup station of the job 1 is an operator station 12. Then, the operator station 12 is activated and takes charge of the execution of the job 1 in place of the operator station 11. Thus, since each operator station backs up for the unit of the job, it is not necessary to especially set up the station equipped with the backup function.

Description

[Detailed Description of the Invention] Industrial Application Fields The present invention relates to a distributed control system that performs control operations on various processes, and in particular, to redundancy of the system. Conventional technology> An operator station that has a CRT display device and monitors the overall control operation, and a control station that receives signals from the process site, performs calculations, and issues control signals are connected to a bus. In a distributed control system, in order to prepare for work interruption in the event of a failure of an operator station, stations with exactly the same capacity and size are installed on the bus, creating hardware redundancy in the system. ．． Problems to be Solved by the Invention However, recently, systems in which multiple operator stations are installed on a bus are often constructed, and an equivalent station is installed between each operator station within the system to back up control operations. In order to install the same number of machines, it was necessary to increase the amount of hardware, which led to problems such as higher costs and larger size. There is also a system in which a computer station is installed in the system in addition to the operator station and control station, and all work is set on this computer station, and the work details are sent and instructed to the operator station and control station. However, such systems did not have measures in place in the event that the computer station malfunctioned. The present invention aims to solve the above-mentioned problems, and aims to provide system redundancy without increasing hardware.

Means for Solving the Problems> The present invention, which has solved the above problems, divides work into job units of one function and backs them up at multiple operator stations, and its configuration is as follows. That's right. That is, at least one control station that performs control calculations and sends and receives signals to various controlled objects, and at least two operator stations that monitor these control stations are connected to a bus. In a distributed control system, the work to be set at the operator station is divided into jobs for each function,
a storage means for storing, in each of the operator stations, the job number, the operator station number at which the job is to be executed, and the operator station number at which the job is to be backed up in a ledger format; This is a distributed control system characterized by having a job file that stores jobs to be executed and jobs to be backed up. Effects> In the split control system of the present invention, when a failure of an operator station is discovered, the operator station corresponding to the job number currently being executed is stored in each operator station in ledger form. The station starts the job on its behalf. Embodiment> An embodiment of the distributed control system of the present invention will be described below with reference to the drawings. FIG. 1 is a functional block diagram showing the split control system of the present invention. The system in this figure consists of operator stations 11,
12, 13, computer station 2, control station 31. In this example, 32 stations are interconnected by bus B, and three operator stations 11, 12. No. 13 has the same configuration. Also, each operator station 11,
12. 13 is the identification number (in this example, 11,
12. 13) is added in advance. Note that the control station 31 controls the controlled object S1, and the control station 32 controls the controlled object S2. Furthermore, each operator station 1 according to the system of the present invention
t, 12. 13, the ledger 11,
12. Set 13. These ledgers 11, 12
, L3 is set to register the job number, backup station number, and execution station number. The backup station and execution station are selected and registered from the operator stations in this system. Furthermore, the actual content of the job is determined at each operator station 11, 12. Register in job files N, F2, and F3 in 13. Here, an example of a job that is set in the system of the present invention and should be made redundant is the stock management job as shown in FIG. This brand management is performed by controlling valves V1, V2 from tanks T1, T2, ..., Tn, which store different liquid products.
, V3 and output via pipe P'L1B1, B2,
..., the job is to ship liquid products from Bl, and job 1 is to ship the product in tank 11 from 1001 exit B1, and job 2 is to ship the product in tank Tn to 200.
Shipped from output 11B2, product in tank T2 as job 3 100. This is an example of shipping from li exit Bl1. The case where the above job is set and executed in the system as shown in FIG. 1 will be explained in detail using the flowcharts shown in FIGS. 2(a) and 2(b). Figure 2(a) is
Jobs 1, 2, 3, etc. from operator station view
This is a flowchart showing the operation when reserving and registering... For example, when operator station 11 starts reservation for job 1, it sets job number 1 to machine #i[1, specifies backup station 12 to back up job 1, and executes job 1. Set up station 11. Since the operator station 11 is the execution station for job 1, the contents of job 1 are stored in its own job file F.
In addition, operator station 11 has job number 1 and backup station number 12.
, execution station 11 via a bus to operator station 12 . Send to Ledger 12, L3 in 13. Note that the operator station 12 is
Since it is a backup station for operator station 11, it also sends the contents of job 1,
Store the contents of job 1 in job file F2. Similarly, for job 2, the contents of job 2, backup station 13, and execution station 12 are input from the operator station 11, and these job number 2, backup station number 13,
Set execution station number 12 to operator station 12. Ledger in 13 12. 13, and also sends the contents of job 2 to the execution station 12 and backup station 13. Operator station 12. In step 13, the contents of job 2 are stored in job files F2 and F3. By repeating the above operations, the operator
Station 11, 12. Ledger 11 in 13, 1
The same content is set in 2 and L3, and the job file “
1. The contents of the job to be executed by the operator station and the contents of the job to be backed up are set in F2 and F3. In addition, operator stations 11, 12. 13 have the same configuration, the input work for job numbers and their contents, backup station numbers, and execution station numbers is not limited to operator station 11, but is the same regardless of which operator station they are input from. This completes the job setting work. Next, assuming that the job execution has started, explanation will be given using the flowchart shown in FIG. 2(b). Operator stations 11, 12. Specify the job execution command using one of the following options. For example, when operator station 13 commands to start executing job 1, this execution start message is sent to bus B.
via operator station 11. 12 to each operator station 11, 12. 1
3 is your own ledger 11, 12. 13, and if you are the execution station, start executing the job. Here, since the execution station of job 1 is operator station 11, operator station 11 starts its execution, and the execution station of job 1 is transferred to other operator stations 12. Notify 13. Also, job execution is performed from the operator station side to the control stations 31, 321I1! When transitioning to I, the control station monitor notifies the operator station of job execution transition. In such a job execution state, each operator station 11, 12 . 13 mutually monitor their operating status. Then, when a failure (down) of the operator station 11 executing job 1 is detected, the operator station that detected the failure activates the backup station for job 1 according to the internal lever. In this case, the execution station is operator station 11, the backup station for job 1 is operator station 12, and the
Station 12 is activated and takes charge of executing job 1 on behalf of operator station 11. At this time, in order to prevent duplicate execution of one job, the operator reserved as the execution station
Interrupt the operation of station 1. After that, the downed operator station 11 is monitored, and if it returns to normal, each backup station will be in charge of the jobs registered in the ledger 11 at this point, and from then on, the jobs newly registered in the station IL1 will be handled. Then, the operator station 11 starts its execution. Furthermore, for job 2.3, the execution station and backup station are activated in the same manner. In this way, the present invention configures a system in which each operator station backs up each job. In addition, although the example in which three operator stations are connected to the system has been described in FIG. 1, the number of operator stations is not limited to three. There are also systems that reserve jobs to be executed on computer station 2, but even in such systems, the job number, execution station number,
If the backup station number is managed in a ledger at each operator station, backup will be ensured even if computer station 2 goes down, without having to set up a computer station with equivalent functionality in the system. <Effects of the Invention> As described above, according to the distributed control system of the present invention, each operator station backs up each other through ledger management on a job-by-job basis. There is no need to install the system at a specific station, and the load for backup functions at a specific station can be reduced. Furthermore, even if a particular station, such as a computer station on which jobs are collectively set, goes down, the entire system can continue working.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the horizontal control of a distributed control system implementing the present invention, Figures 2 (a) and (b) are flowcharts representing the operation of the system of the present invention, and Figure 3 is a diagram showing the settings of the system of the present invention. This is a diagram showing an example of a job. 11 12. 13... Operator station, 2... Computer station, 31.32.
...Control station, B...Bus, ((L) Figure Z (b)

Claims (1)

[Claims] (1) At least one control station that performs control calculations and sends and receives signals to and from various controlled objects, and at least two operator stations that monitor these control stations are connected to a bus. In a distributed control system, the work to be set at the operator station is divided into jobs for each function,
a storage means for storing, in each of the operator stations, the job number, the operator station number at which the job is to be executed, and the operator station number at which the job is to be backed up in a ledger format; 1. A distributed control system comprising a job file storing jobs to be executed and jobs to be backed up.