JP4025540B2 - Multiplexing controller - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a multiplexing control apparatus that includes a plurality of process control operation units and performs control multiplexed by these.
[0002]
[Prior art]
In general, multiplexing control is performed in the case where high reliability is required for process control such as a power plant. In multiplexed control, arithmetic processing for control of one control target device is performed in parallel in a plurality of process control arithmetic units, and for example, from each control signal obtained by the multiple parallel processing, for example, low value priority, high value priority, Selection is made by intermediate value priority or majority decision, and the selection result is output as an actual control signal. In the conventional multiplexing control apparatus, selection circuits such as a low value priority circuit, a high value priority circuit, an intermediate value selection circuit, and a majority decision circuit are provided, and the selection is performed by these selection circuits. As such a multiplexing control device, examples disclosed in, for example, Japanese Patent Laid-Open Nos. 61-52701, 7-261802, and 9-44203 are known.
[0003]
[Problems to be solved by the invention]
For a control system using a multiplexing control device, downsizing of the control system is an important issue as well as high reliability. From the viewpoint of downsizing, the prior art (prior art 1) disclosed in Japanese Patent Laid-Open No. 61-52701 is insufficient. That is, in the prior art 1, a signal selection circuit is provided for each of a plurality of controlled objects handled by one multiplexing control apparatus, and the amount of hardware of the signal selecting circuit increases as the number of controlled objects increases. In addition, the number of signal cables connecting the multiplexing control device and each signal selection circuit is increased, thereby increasing the size of the control system.
[0004]
The conventional technique (conventional technique 2) disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 7-261802 proposes a structure for solving such a problem in the conventional technique 1. FIG. 5 schematically shows an example of the configuration of a multiplexing control apparatus when the prior art 2 is actually applied. This is an example of triple control, and the multiplexing control device is provided with three process control operation units 101, 102, and 103, which are connected via the network 108 and can send and receive data to and from each other. ing. Each process control arithmetic unit performs the same control arithmetic processing asynchronously and sends the result to the process signal input / output unit 161 via the interfaces 111, 121, 131 of each process control arithmetic unit. The process signal input / output unit is provided with a plurality of process signal input / output cards 171a to 171n. In these process signal input / output cards, a signal selection circuit 181 is incorporated together with a signal conversion circuit and a determination circuit. With this signal selection circuit, a low value selection, a high value selection, Selection is performed by intermediate value selection or majority decision, and the result is output to the controlled object as a control signal.
[0005]
As described above, in the prior art 2, a signal selection circuit is mounted on a process signal input / output card incorporated in a process signal input / output unit (on-site panel in Japanese Patent Application Laid-Open No. 7-261802). Common to controlled objects. As a result, it is possible to reduce the amount of hardware of the signal selection circuit as compared with the prior art 1, and it is possible to reduce the number of necessary signal cables. However, the structure of the prior art 2 still has a considerable amount of hardware problems associated with the signal selection circuit. That is, since the number of mounted parts of the process signal input / output card increases and the circuit configuration becomes complicated, the number of input / output signals that can be handled by one card, that is, the number of controlled objects that can be handled by one card is relatively small. For this reason, the number of cards increases and the size of the process signal input / output unit increases. In addition, by mounting a signal selection circuit of selection logic corresponding to the controlled object, the process signal input / output card is dedicated, and the assembly of the process signal input / output unit becomes complicated.
[0006]
The present invention has been made against the background of the above-described conventional circumstances, and the object of the present invention is to provide a multiplexing control device that can achieve further compactness and ensure the same reliability as the conventional one. It is to provide.
[0007]
[Means for Solving the Problems]
The present invention includes a plurality of control arithmetic units,
A PI / O unit interposed between the controlled object and the plurality of control calculation units;
An external determination circuit;
With
Each control calculation unit
Output means for outputting a control signal to be the actual control system when the other control arithmetic unit is not in the actual control system state and there is no abnormality in the own system and is at the highest level in accordance with a predetermined priority order When,
The control processing for the same controlled object is performed asynchronously with each other to obtain a self-calculation result signal, which is output to another control calculation unit, and the other calculation result signal output from the other control calculation unit A calculation means for outputting a self-selection calculation result signal selected from the comparison with the self-calculation result signal;
In addition to performing self-diagnosis, mutual diagnosis of calculation result signals and self-calculation result signals taken from other control calculation units is performed, and external determination of these normal / abnormal self-diagnosis results and normal / abnormal mutual diagnosis results Diagnostic means for sending to the circuit;
With
PI / O unit is
The first and second switching paths are interposed in series for each system path connecting the controlled object and each control calculation section, and the output means of the corresponding control calculation section should be the actual control system in the first switching path. Closed by the control signal and controlled to open when in the standby system ,
The external judgment circuit
Each control unit includes a determination unit corresponding to each control calculation unit, and each determination unit takes in a self-diagnosis result from a corresponding control calculation unit, a self-diagnosis result from a non-corresponding control calculation unit, and a mutual diagnosis result, When the self-diagnosis result of the part is abnormal or all of the self-diagnosis results of the non-corresponding control arithmetic part are normal and all of the mutual diagnosis results to the corresponding control arithmetic part in the non-corresponding control arithmetic part are abnormal At this time, a control signal for opening the second switching path of the corresponding PI / O unit from the previous closing to the opening is generated.
A multiplexing apparatus characterized by the above is disclosed.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below. FIG. 1 schematically shows the configuration of a multiplexing control apparatus according to an embodiment. The multiplexing control apparatus according to the present embodiment is an example of triple control, and includes three process control operation units 1, 2, and 3 that are connected via the network 8 and can send and receive data to each other. I have. These process control arithmetic units 1, 2, and 3 have a signal selection function by software, and in addition to control arithmetic processing, selection is also made for the arithmetic processing result. Specifically, the three process control arithmetic units 1, 2, and 3 perform control arithmetic processing for the same controlled object in an asynchronous manner in parallel. Signals obtained as a result of the calculation are exchanged with each other via the network 8, and each process control calculation unit also obtains a calculation result signal of another system in addition to the result of its own system. Then, each process control calculation unit or a process control calculation unit set as a single actual control system as described later selects one signal from the three calculation result signals by the own system and the other system by the signal selection function. For the analog signal, the triple control systems including the process control arithmetic units 1, 2, 3 and the interfaces 11, 21, 31 provided for each of these process control arithmetic units are normal for analog signals. If there is an abnormality in one system and the remaining two systems are normal, the low value selection or the high value selection is performed. On the other hand, for a digital signal, majority selection is used on condition that each of the triple control systems is normal.
[0012]
The selected signal is output to the process signal input / output unit 61 via any one of the interfaces 11, 21, and 31 as one of the three process control operation units as an actual control output, that is, an actual output. The process signal input / output unit 61 is provided with a plurality of process signal input / output cards 71a to 71n. These process signal input / output cards 71a to 71n have only a signal conversion function of converting a digital signal into an analog signal and converting an analog signal into a digital signal. The signal is input to the process control operation unit such as the open / close signal of the signal and the output from the process control operation unit to the controlled object.
[0013]
As described above, in the configuration in which the process control operation unit performs signal selection by software, each process control operation unit has an equivalent qualification regarding the actual output. Therefore, a single actual control system that is allowed to produce actual output and a standby system that performs computation and abnormality diagnosis described later but does not perform actual output are set. The only actual control system is set as follows. Priorities are set in advance for each process control operation unit. And the only real control of the process control arithmetic unit with high priority is provided on condition that the other process control arithmetic unit is not in the state of the actual control system and that the self-diagnostic system described below is normal. System. For example, the contact point 11a at the interface is brought into a connected state only for the process control operation unit 1, which is the only actual control system.
[0014]
In addition, regarding the configuration in which signal selection is performed by software in the process control operation unit, it is important from the viewpoint of ensuring reliability to cope with an abnormality in each process control operation unit and each control system including it. . In the present invention, with respect to ensuring the reliability, each process control operation unit performs self-diagnosis to determine normality / abnormality of the own system, and mutual diagnosis to determine normality / abnormality of other systems between the process control operation units To do. Further, an external determination circuit 5 having a hardware structure is provided to separate the abnormal control system from the control state based on these diagnosis results.
[0015]
The self-diagnosis is performed by judging abnormality of own system hardware (CPU, interface circuit, etc.) and software, upper / lower limit abnormality of input signal, calculation result abnormality, and the like. The abnormality of the calculation result is determined by comparing the calculation result of the own system with the calculation result of the other system and whether the deviation is equal to or greater than a certain value. On the other hand, in the mutual diagnosis, the calculation results of the respective process control calculation units are compared, and when there is a certain deviation or more between the calculation result of one system and the calculation result of the other two systems, for example, the process control calculation unit 1 When the calculation result of (A system) has a certain deviation from the calculation result of process control calculation units 2 and 3 (B system and C system), the process control calculation units 2 and 3 Diagnose part 1 as abnormal.
[0016]
FIG. 2 shows a determination logic configuration of the external determination circuit 5, and FIG. 3 shows an example of a circuit configuration that can be used therefor. Although only the A system is shown in FIG. 3, the same applies to the B system and the C system, and the external determination circuit 5 includes these three systems. The system A in the figure will be described. A contact 51 and a contact 52 that are opened and closed according to the results of the determination of the normality / abnormality of the hardware system and the normal / abnormality of the software system in the self-diagnosis of the A system are connected in series. The A system determination result section, the contact 53 and the contact 54 that are opened / closed in parallel according to the determination results of the normal / abnormality of the hardware system in the self-diagnosis of the B system and the normal / abnormality of the A system in the mutual diagnosis The connected B system determination result section, and the contacts 55 and 56 that are opened / closed according to the determination results of the normality / abnormality of the hardware system in the self-diagnosis of the C system and the normal / abnormality of the A system in the mutual diagnosis. Are connected to each other in parallel. The B system determination result unit and the C system determination result unit are provided in parallel, and are provided in series with the A system determination result unit. Further, the contacts 51, 52, 54, and 56 are closed by normality determination, and the contacts 53 and 55 are closed by abnormality determination. The contact points 53 and 55 are closed by the abnormality determination so that the B system and the C system can determine the normality / abnormality of the A system on the condition that the own system is normal. Therefore, the normal / abnormal determination of the A system by the external determination circuit 5 is determined to be abnormal when the self-diagnosis result is abnormal, and even if the self-diagnosis result is not abnormal, it is determined to be abnormal from another system by mutual diagnosis. Is determined to be abnormal. However, the mutual diagnosis result is that neither the B system nor the C system is abnormal. This determination result is output to the interface, and in the case of an abnormality, the system A is disconnected from the control state by opening the contact 11b of the interface.
[0017]
As described above, the multiplexing control device according to the present invention is configured so that the signal selection function is softened and imposed on the process control operation unit, so that the structure of the process signal input / output card can be simplified. The function of the process signal input / output card can be completed only by the signal conversion function, and the generalization of the process signal input / output card can be enhanced. As a result, the multiplexing control device and the control system using the same can be made more compact. On the other hand, it is possible to diagnose the presence or absence of abnormality by self-diagnosis and mutual diagnosis by software, and according to the result, an external judgment circuit is provided that performs separation operation of the process control arithmetic unit with a hardware structure Therefore, high reliability can be secured.
[0018]
FIG. 4 shows the configuration of a reactor water supply flow rate control device and a reactor recirculation flow rate control device of a nuclear power plant that is an example of a suitable application target of the multiplexing control device according to the present invention. The reactor water supply flow rate control device 81 controls the water supply flow rate by operating the water supply pump 83 based on the water level signal in order to keep the water level of the reactor 82 appropriate. On the other hand, the reactor recirculation flow rate control device 84 appropriately controls the recirculation pump 85 that adjusts the reactor power by circulating the water in the reactor based on the reactor power. Both of these control devices are important control systems in nuclear power plants, and very high reliability is required. At the same time, there is a strong demand for cost reduction through downsizing due to the liberalization of power. The multiplexing control apparatus according to the present invention is particularly suitable for taking advantage of the features of high reliability and compactness. In the figure, reference numeral 86 denotes a turbine and a generator, reference numeral 87 denotes a condenser, and reference numeral 88 denotes a condensate pump.
[0019]
【The invention's effect】
As described above, according to the present invention, the multiplexing control device can be made more compact by making the selection function of the signals output from the plurality of process control arithmetic units software and causing the process control arithmetic unit to perform the function. Peeled off. In addition to providing this selection function as software, an abnormality diagnosis function such as a process control operation unit is provided, and an external determination circuit having a hardware structure is provided, so that high reliability can be realized. As a result, the control system is strongly required to be compact with high reliability. For example, it can greatly contribute to cost reduction of a nuclear power plant.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a multiplexing control apparatus according to an embodiment.
FIG. 2 is a flowchart of determination logic in an external determination circuit.
FIG. 3 is a circuit configuration diagram of an external determination circuit.
FIG. 4 is a configuration diagram of a nuclear power plant suitable for applying a multiplexing control device.
FIG. 5 is a configuration diagram of a conventional multiplexing control apparatus.
[Explanation of symbols]
1, 2, 3 Process control operation unit 11, 21, 31 Interface 5 External determination circuit

Claims (1)

A plurality of control operation units;
A PI / O unit interposed between the controlled object and the plurality of control calculation units;
An external determination circuit;
With
Each control calculation unit
Output means for outputting a control signal to be the actual control system when the other control arithmetic unit is not in the actual control system state and there is no abnormality in the own system and is at the highest level in accordance with a predetermined priority order When,
The control processing for the same controlled object is performed asynchronously with each other to obtain a self-calculation result signal, which is output to another control calculation unit, and the other calculation result signal output from the other control calculation unit A calculation means for outputting a self-selection calculation result signal selected from the comparison with the self-calculation result signal;
In addition to performing self-diagnosis, mutual diagnosis of calculation result signals and self-calculation result signals taken from other control calculation units is performed, and external determination of these normal / abnormal self-diagnosis results and normal / abnormal mutual diagnosis results Diagnostic means for sending to the circuit;
With
PI / O unit is
The first and second switching paths are interposed in series for each system path connecting the controlled object and each control calculation section, and the output means of the corresponding control calculation section should be the actual control system in the first switching path. Closed by the control signal and controlled to open when in the standby system ,
The external judgment circuit
Each control unit includes a determination unit corresponding to each control calculation unit, and each determination unit takes in a self-diagnosis result from a corresponding control calculation unit, a self-diagnosis result from a non-corresponding control calculation unit, and a mutual diagnosis result, When the self-diagnosis result of the part is abnormal or all of the self-diagnosis results of the non-corresponding control arithmetic part are normal and all of the mutual diagnosis results to the corresponding control arithmetic part in the non-corresponding control arithmetic part are abnormal At this time, a control signal for opening the second switching path of the corresponding PI / O unit from the previous closing to the opening is generated.
A multiplexing device characterized by the above.

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