JPH11175104A - Decentralized controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid adverse influence on a plant even when a fault occurs in a CPU module for commanding or when an application program has a registration error. SOLUTION: The decentralized controller is provided with plural CPU modules 1-1 ,... and 1-n for control operation, input modules 2-1 ,... and 2-n for fetching an external signal, control output modules 3-1 ,... and 3-n for outputting the signal to an external part and a bus line 4. Then, the control output modules 3-1 ,... and 3-i detect fault in a control arithmetic part to give instruction to the control output modules 3- ,... and 3-i and a registration error in the application program, respond to the detection of the fault or the registration error, to turn a signal output part into a manual mode.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distributed control device used in a production plant, a plant for controlling a boiler, and the like.

[0002]

2. Description of the Related Art Generally, a distributed control device for controlling a plant includes a plurality of control operation units (CPs) for performing digital operations.
U module), a signal input unit (input module) for receiving a signal from the plant, a signal output unit (control output module) for outputting a signal to the plant, and a control operation unit, a signal input unit, and a signal output unit. A bus line to be connected, a signal from the plant is taken in from the signal input unit through the bus line to the control operation unit, a predetermined operation is performed by the control operation unit, and the operation result is transmitted to the plant from the bus line and the signal output unit. Output.

[0003]

In the above-mentioned conventional distributed control apparatus, when a failure occurs in a CPU module instructing a control output module, or when there is a registration error of an application program in which there are a plurality of CPU modules instructing. In such a case, if the control output is continuously output as it is, the effect on the plant becomes large.

[0004] The present invention has been made in view of the above problems, and avoids the influence on the plant caused by a failure of a commanding CPU module or a registration error in an application program. It is an object of the present invention to provide a decentralized control device which can be used.

[0005]

According to the present invention, there is provided a distributed control apparatus comprising: a plurality of control operation units for performing a control operation; a signal input unit for receiving an external signal; and a signal output unit for outputting a signal to the outside. And a bus line for connecting the control operation unit, the signal input unit, and the signal output unit, wherein the signal output unit detects a failure of the control operation unit instructing the signal output unit and a registration error of the application program. Means,
Means for manually switching in response to the detection of the failure or registration error.

In this decentralized control device, when a failure occurs in the control operation unit that instructs the signal output unit, or when there is a registration error of an application program in which there are a plurality of CPU modules that instruct the signal output unit, the signal output unit transmits the information. And output manually. By using manual operation, it is possible to prevent the failure of the control operation unit and the registration error of the application program from affecting the plant.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The light will be described in more detail. FIG. 1 shows one embodiment of the present invention.
FIG. 2 is a block diagram illustrating a configuration of a configuration distributed control device. This
Distributed control device has a plurality of CPU modules (control functions).
Calculation part) 1_-1, ..., 1_-nAnd the input module (signal input
Part) 2_-1, ..., 2_-mAnd the control output module (signal output
Force part) 3_-1, ..., 3_-iAnd these CPU modules 1
_-1, ..., 1 _-n, Input module 2_-1, ..., 2_-m, System
Output module 3_-1, ..., 3_-iConnect the bus line
4. In this distributed control device, usually,
Input module 2 from the signal from the plant_-1, ..., 2_-m
CPU module 1 through the bus line 4_-1…
... 1_-nAnd execute the control calculation. The operation result
The bus line 4, the control output module 3_-1, ..., 3_-i
Output to plant.

[0008] This distributed control device adds, to an application program containing a control operation to be executed by a CPU module, one that specifies a control output module instructed by the CPU module. Figure 2 shows an example
Shown in In the example of FIG. 2, the control output module table is called, and the number of tables is the same as the maximum number of control output modules that can be used.
When the flag is not set to 0, it indicates that it is not used. FIG. 2 is an example in which the corresponding flags of the control output module 2 and the control output module n-1 are set.

Here, the processing operation of the CPU module 1 will be described with reference to the flowchart of FIG. When a regular (eg, every 100 ms) processing timing arrives (step ST1), the CPU module 1 sets the variable I to 1 (step ST2), refers to the control output module table, and obtains the I = first control output module. It is checked whether the flag has been set (step ST3).
If the flag is set, the control output module I writes a preset value (for example, 10) to the counter of the location of the own CPU module in the CPU module diagnosis table on the control output module I (step ST4).
FIG. 3 shows an example of the CPU module diagnosis table. FIG.
Indicates that the No. 2 CPU module uses the control output module.

After the preset processing in step ST4, the variable I is incremented by one (step ST5).
Is greater than n (step ST6), step ST3
And repeat the steps ST3 to ST6 to write the preset value to the counter of the location of the own CPU module in the CPU module diagnosis table on each control output module for which the flag is set.

As shown in FIG. 5, in each control output module 3, when a regular (eg, every 100 ms) processing timing comes (step ST11), the count value of the CPU module diagnosis table is subtracted (step ST1).
2). Here, the CP instructing the control output module
The diagnostic table counter of the U module does not become 0 because it is periodically preset in the processing of step ST4 in the CPU module. Therefore, the CPU module of the counter that has counted up, that is, has become 0, determines that there is no command to the control output module. Therefore, the CPU diagnosis module diagnosis table is checked, and if all the counter values are 0, it is diagnosed that the CPU module has failed and the mode is switched to the manual mode.

Further, even if all the counters have not been counted up and the determination in step ST13 is NO, it is determined whether or not the number of counters which have not been counted up is 2 or more (step ST1).
4) If the determination is YES, that is, if there are two or more counters whose count value is not 0, it is determined that there are two or more CPU modules for instructing the control output module. (Step ST15).

If the number of counters counted up in step ST14 is not 2 or more, that is, if there is only one CPU module instructing the control output module, the process is terminated as it is, and the program returns to the next step. Prepare for the arrival of processing timing.

[0014]

According to the present invention, the signal output unit (control output module) has means for detecting a failure of the control operation unit for instructing the signal output unit and a registration error of the application program. A means for switching to manual operation in response to the detection is provided.In the conventional device, only the abnormality of the signal output unit alone could be switched to manual operation. On the other hand, this can be detected, and these can also be manually switched at the signal output unit, thereby preventing an adverse effect on the plant.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a distributed control device according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a control output module table provided on a CPU module of the distributed control device of the embodiment in FIG. 1;

FIG. 3 is a diagram illustrating a CPU module diagnostic table provided on a control output module of the distributed control device of the embodiment in FIG. 1;

FIG. 4 is a flowchart for explaining a processing operation of a CPU module of the distributed control apparatus of the embodiment in FIG. 1;

FIG. 5 is a flowchart for explaining a processing operation of a control output module of the distributed control device of the embodiment in FIG. 1;

[Explanation of symbols]

1 _-1 ,..., 1- _n CPU module 2 _-1 ,..., 2- _m input module 3 _-1 ,..., 3- _i control output module 4 bus line

Claims (1)

[Claims] 1. A plurality of control operation units for performing a control operation, a signal input unit for receiving an external signal, a signal output unit for outputting a signal to the outside, a control operation unit, a signal input unit, and a signal output unit And a bus line for connecting to the signal output unit, wherein the signal output unit detects a failure of the control operation unit instructing the signal output unit, a registration error of the application program, and a detection of the failure or the registration error. And a means for manually switching in response to the command.