JP2000305601A - Plant controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a plant controller which improves the reliability of output circuits. SOLUTION: This controller is provided with four output circuits of digital signal output devices 140, amplifier circuits 142 for operating three contacts with their output signals in each output circuit and a decision logic circuit which decides an output by the establishment of plural (two) or more output signals from each output circuit by the twelve amplification contacts 143 in total of the four output circuits.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plant control device in a chemical plant, a power distribution and power generation plant, and more particularly to a redundant output circuit for improving the reliability of the output circuit.

[0002]

2. Description of the Related Art FIG. 21 is a circuit diagram showing a schematic configuration of a conventional interlock system used in, for example, a chemical plant. In the figure, reference numeral 10 denotes a plant, and 16 denotes an actuator related to an interlock operation in the plant 10. Reference numeral 2 denotes an input circuit for inputting information from the plant 10, which is multiplexed (triple). 1 is a triple CPU that performs a control operation related to the interlock, and 3 is a CP.
This is a dedicated output circuit that determines a signal from U1 and converts the control logic signal into a relay signal 15 necessary for driving an actuator 16 in the plant 10.

Next, the operation will be described. When the multiplexed CPU 1 detects an abnormality in the S / W logic from the input condition input by the input circuit 2, the CPU 1 outputs an output signal for safely stopping the plant 10 when the abnormality is detected, to a dedicated output circuit. Output to 3. The dedicated output circuit 3 constitutes majority logic (2 out of 3),
If there are two or more output signals among the three CPUs 1, they are output. That is, one of the three CPUs 1
1 constitutes a redundant circuit that does not malfunction as an interlock system even if an output signal is erroneously output due to a failure or the like.

[0004]

The conventional interlock system is configured as described above, and the CPU 1 is multiplexed and has a highly reliable interlock due to the judgment function by the majority logic in the preceding stage in the dedicated output circuit 3. Lock operation is ensured. However, it is assumed that sufficient reliability is ensured for a portion that functions as an output circuit at a subsequent stage in the dedicated output circuit 3, that is, a portion that converts a control logic signal determined by majority logic to a relay signal. I can't say. Specifically, this output circuit portion converts an on-change of an operation command signal of DC5V level from the CPU 1 into a signal necessary for a relay operation via a photocoupler, and includes a circuit configuration including various components. Consists of a body. Therefore, if an abnormality occurs in one of these components, normal operation characteristics cannot be obtained as an output circuit, and the interlock function will be impaired.

The present invention has been made to solve the above problems, and has as its object to obtain a plant control device in which the reliability of an output circuit is improved. It is another object of the present invention to realize versatility of the output circuit.

[0006]

A plant control apparatus according to the present invention comprises a control circuit for generating a control logic signal for controlling a plant, and a control logic signal from the control circuit for driving a device in the plant. In a plant control apparatus provided with an output circuit for converting the output signal into a relay signal necessary for performing the operation, a plurality (three or more) of the output circuits are provided with a common input side, and a plurality of (2 The above is provided with a multiple selection circuit for determining the output when the condition is satisfied.

Further, the plant control device according to the present invention is provided with four output circuits, and the multiple selection circuit includes an amplifier circuit for operating three contacts by an output signal for each of the output circuits; And a judgment logic circuit for judging an output when a plurality of (two or more) output signals from the respective output circuits are established by a total of twelve contacts of the output circuit.

Further, the plant control apparatus according to the present invention includes an answerback circuit for individually determining each output signal of the plurality of output circuits, and operates the answerback circuit in serial with the timing of the control operation of the plant. Thus, the presence or absence of an abnormality in each of the output circuits is constantly monitored.

Further, in the plant control device according to the present invention, when four output circuits are provided, when an abnormality of one output circuit is detected, the remaining three circuits excluding the abnormal output circuit are detected.
A selection processing unit for selecting the output circuit so as to make an output determination based on a plurality of output circuits based on output signals from the plurality of output circuits.

[0010] Also, a plant control device according to the present invention is a device signal generation circuit for generating a device selection signal output when selecting a predetermined device in a plant and a device output signal output when driving the device. And a plant control device having an output circuit that converts the device signal into a relay signal required to drive the plant device, wherein the amplifier circuit operates a contact with the output signal for each output circuit, and A judgment logic circuit for judging an output when a logical product of output signals from the output circuits is established by a contact is provided.

Further, the plant control device according to the present invention includes an equipment signal generation circuit and an output circuit for a service system and a standby system, respectively, and the determination logic circuit includes a logical product of an output signal in the service system and a standby system. The output is determined when the logical sum of the output signal and the logical product is established.

Further, a plant control device according to the present invention provides a control circuit for creating a control logic signal for controlling a plant, and a control logic signal from the control circuit for driving equipment in the plant. In a plant control device provided with an output circuit for converting to a relay signal,
In the process of replacing the control circuit and output circuit,
When the existing system to be removed and the newly installed update system coexist, an amplification circuit that operates a contact with the output signal for each output circuit of the two systems, and a logical sum of the output signals from each of the output circuits by the contact By providing a determination logic circuit that determines the output when the condition is satisfied, the downtime of the plant accompanying the replacement work can be reduced.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 shows a plant control apparatus according to Embodiment 1 of the present invention.
21 shows a case where the present invention is applied as an interlock system, similarly to FIG. In the figure, reference numeral 10 denotes a plant such as a chemical plant, a power distribution plant, a power generation plant,
1 is a controller as a control circuit for monitoring and controlling operation, 13 is an input circuit of the controller 11, 14 is an output circuit of the controller 11, and a plurality of output circuits are provided for one control logic signal as described later. Have been. 1
Reference numeral 2 denotes a multiple selection circuit, the details of which will be described later. Reference numeral 15 denotes an output signal (relay signal) that is actually output, and reference numeral 16 denotes an actuator such as a shutoff valve that operates in an emergency of the plant.

FIG. 2 is a block diagram more specifically showing the configuration of the portion of the controller 11 in FIG. 1. The first two digits in the figure correspond to those in the block diagram in FIG. I have. In FIG. 2, reference numeral 110 denotes a duplicated CPU,
111 is a duplicated power supply device, 130 is a digital signal input device, 131 is an analog signal input device, and 140 is a digital signal output device, which here comprises four output circuits whose input sides are common. 141 is an analog signal output device.

FIG. 3 is a block diagram more specifically showing the configuration of the portion of the multiplex selection circuit 12 of FIG. 1. The first two digits of the reference numerals in FIG. 3 correspond to those shown in the block diagram of FIG. Let me. In FIG. 3, reference numeral 120 denotes a determination logic circuit,
A plurality (2) of output signals from four output circuits of the digital signal output device 140 are established, so-called 2 out of 4
Is determined. 121 is a digital signal output device 140
An output signal for amplifying the signal from the input terminal and outputting the amplified signal to the digital signal input device 130 as an answerback signal;
2 represents one signal from the digital signal output device 140 as 3
An output signal amplified to two signals, 126 is a relay for outputting an output contact 127 to the plant, and 128 is a display device for displaying the operation status of the relay 126 by turning on an LED.

FIG. 4 shows the operation of the decision logic circuit 120 of FIG.
It is a circuit diagram for explaining a working principle. In FIG.
142 is an amplifying circuit, from the digital signal output device 140
Amplify contact 143 is operated by the output signal of. example
For example, in FIG. 3, the output signal from the digital signal output device 140 is output.
The signal DO0 has one answerback signal 121 (0₀₀)When
Three output signals 122 (0₀₁, 0₀₂, 0₀₃) And amplified to
In FIG. 4, the input of these three output signals 122
Amplifier circuit 142 (Y₀) Is the amplification contact 143 (Y₀₁, Y ₀₂,
Y₀₃) Is operated (turned on). 144 is a logical sum (OR)
Circuit.

FIG. 5 shows an example of a configuration in which a plurality of (in this case, four) multi-selection circuits 12 are arranged in parallel and the connection with the digital signal input device 130 and the digital signal output device 140 is made by a connector / card system. 6 and 7 are a front view and a side view showing an outline image of the device. In the figure, 123 is a storage case, 125 is a driver circuit that operates in response to an output signal from the multiple selection circuit 12, and 129 is a snap switch provided for forcibly disconnecting the output. 132 is an output connector for outputting the answer back signal 121 to the contact input card of the digital signal input device 130, and 133 is an output signal 122 from the contact output card of the digital signal output device 140.
This is an input connector for inputting.

Next, the operation will be described. The control logic signal relating to the interlock control created by the controller 11 has four output circuits (DOs) having a common input side.
0, DO1, DO2, DO3), each signal is further amplified into three signals 122, and the amplifying contact 143 operates via the amplifying circuit 142. In the logic circuit shown in FIG. 4, if there are two or more outputs from the four output circuits, the OR circuit 144 outputs the relay signal 15.
That is, the redundancy of the output circuit is realized, and the reliability is dramatically improved. Further, as shown in FIG. 6, a plurality of multiple selection circuits 12 can be accommodated, so that each of the multiple selection circuits 12 can be replaced and maintenance can be facilitated.

Embodiment 2 Here, a description will be given of a device having a function of constantly checking the presence or absence of an abnormality of a plurality of redundant output circuits 14. FIG. 8 shows a flow for performing an abnormality check of the output circuit. It should be noted that this abnormality check flow is performed serially with the timing of the control operation of the plant during the main flow of the plant.

In FIG. 8, first, at step S1, DO
Turn ON 0. Although not shown, it is necessary to provide a contact circuit for individually turning on / off each output circuit for this check function. In step S2, it is checked whether the answer back signal ₀₀ (see FIG. 3) is ON. If it is on (Y, normal), DO0 is turned off in step S3. O in step S2
If N has not been performed (N, when there is an abnormality), D is determined in step S4.
After turning OFF O0, an output abnormality of DO0 is output in step S5. Similarly, in steps S6 to S10, the output abnormality of DO1 is determined. In steps S11 to S15, D0 is determined.
O2 output abnormality, DO in steps S16 to S20
3 to detect the presence or absence of output abnormality. These detection results can be monitored by providing appropriate display means.
Further, a necessary alarm process may be performed depending on the magnitude of the abnormality.

Embodiment 3 Here, the presence / absence of abnormality of four output circuits is detected, and when abnormality of one output circuit is detected, three normal output circuits are automatically selected at that time, and a judgment of 2 out of 3 is made. The one provided with the function that enables the continuation of the logic operation will be described. FIG. 9 shows an operation flow according to the third embodiment of the present invention. In the figure, step S100 shows a process of determining whether there is an abnormality in the output circuit shown in FIG. Step S101 shows a process of selecting an output pattern based on the determination result in step S100.

Then, in step S102 of this option,
Shows processing (output pattern 1) when DO3 is abnormal. Step S103 shows a process when DO0 is abnormal (output pattern 2). Step S104 is DO
1 shows processing (output pattern 3) when 1 is abnormal.
Step S105 shows the processing when DO2 is abnormal (output pattern 4). After one of the output patterns is selected, the process returns to the main flow such as the shutdown process (step S106), and it is determined whether or not it is time to perform the output check (step S100) in step S107. The flow is continued, and if YES, the output check processing is again performed (step S10).
Perform 0).

FIG. 10 shows a logic circuit for switching an output signal according to the output pattern when an output pattern is selected in step S101 of FIG. In the drawing, 145 is an OR circuit, and 146 is an AND circuit. Also, 151 is a temporary output signal and 152 is a true output signal. Now, for example, when DO3 is abnormal and output pattern 1 is selected, the output of pattern 1 in FIG. 10 becomes the “H” level, and four temporary output signals 151 (DO (0), D (0)
O (1), DO (2), DO (3)), the previous three signals are selected and true output signals 152 (DO0, DO1,
DO2). As described above, even if one output circuit fails, the other three output circuits are automatically selected, and a highly reliable output circuit configuration can be obtained by multiple selection of 2 out of 3.

Embodiment 4 FIG. 11 is a configuration diagram showing a logic circuit according to Embodiment 4 of the present invention. In the figure, 147 is an OR circuit, and 148 is a switch such as a hard switch input from a push button or the like, a CRT of an OPS (operator station), or a soft switch input from a touch panel of an EL display, which operates in a four-stage manner. . By turning on the switch 148, an output signal is forcibly output to the actuator 16 irrespective of whether or not each output circuit is abnormal. The snap switch 129 of FIG.
When used together, the operation can be checked off-line, and an on-site operation check test can be easily performed, thereby improving the efficiency.

Embodiment 5 FIG. FIG. 12 is a diagram showing a configuration of a plant control device according to Embodiment 5 of the present invention. This is similar to the conventional FIG. 21 in that the CPU is tripled, three controllers 11 are provided, and the output signal from the output circuit 14 of each controller 11 is output to the multiple selection circuit 12.
, And using the same decision logic circuit as described in the above embodiment, the so-called 2 out of 3 multiple selection realizes improvement in reliability.

Embodiment 6 FIG. FIG. 13 is a diagram showing a configuration of a plant control device according to Embodiment 6 of the present invention. Here, the controller (device signal generation circuit)
A device selection signal to be output when selecting a predetermined device in the plant and a device output signal to be output when driving the device are generated. Then, by connecting the device selection signal output from the output circuit 14 of the controller and the amplification contact 143 that operates via the amplifier circuit according to the device output signal as shown in the figure, the multiple selection circuit 12 allows the device selection signal and the device It operates as a decision logic circuit that outputs when the logical product with the output signal is established.

As described above, by adding the interlock condition by hardware, erroneous operation of the device can be prevented, and the reliability of the operation can be improved.

Embodiment 7 FIG. 14 is a diagram showing a configuration of a plant control device according to Embodiment 7 of the present invention. In this case, a normal / standby (duplex) system is constructed by using the CPUA and CPUB having the same specifications by developing the configuration shown in FIG. In the figure, a multiple selection circuit 12 includes a logical product (AND) condition of a normal device selection signal (0) and a device output signal (1), a standby device selection signal (2) and a device output signal (3). ) Operates as a decision logic circuit that outputs when the logical sum with the AND condition is satisfied.

As described above, the operation output can always be output from the service system, and if the service system fails, the operation output can be automatically output from the standby system, thereby improving the reliability of the system. Can be expected. Since the service system and the standby system are CPUs having the same specifications, the monitoring / control S / W may be the same, and high efficiency can be expected in terms of S / W productivity.

FIG. 15 also has the same configuration as FIG.
Here, the main system and C of this main system
A backup system equipped with CPUB, which has a simpler configuration than PUA, has been constructed. About operation and effect,
The description is omitted because it is the same as the case of FIG.

Embodiment 8 FIG. Here, controller 1
A case will be described in which, when the existing system to be removed is to be replaced with a new update system, the multiple selection circuit 12 can be effectively used to shorten the plant stoppage due to the replacement work. When replacing the existing system shown in FIG. 16 with the update system, the conventional method first removes the existing system, and then,
A new update system is installed to perform necessary wiring work.
The outage of the plant due to the replacement work had to be long.

However, in this embodiment, as shown in FIG. 20, the multiple selection circuit 12 provided with a decision logic circuit that forms an OR circuit with the amplification contact 143 is first provided in FIG.
As shown in FIG. 7, it is inserted between the output circuit 14 of the existing system and the plant 10. Next, as shown in FIG.
An update system will be newly established to coexist with the existing system. Then, the output signals from the output circuits 14 of both systems are input to the multiple selection circuit 12, and the determination logic circuit of the multiple selection circuit 12 can output a logical sum signal of both output signals. Thereafter, as shown in FIG. 19, the existing system is removed and the operation shifts to the operation of the update system.

As described above, the multi-selection circuit for outputting when the logical sum of the output signals of the existing and updated systems is established is provided.
Since both systems are replaced, it is possible to greatly reduce the downtime of the plant due to the replacement work. Further, this multiple selection circuit can be used at the next system update, and can perform economical system update.

[0034]

As described above, the plant control apparatus according to the present invention provides a control circuit for creating a control logic signal for controlling a plant, and a control logic signal from the control circuit for controlling equipment in the plant. In a plant control apparatus provided with an output circuit for converting into a relay signal necessary for driving, a plurality (three or more) of the output circuits are provided with a common input side, and a plurality of output signals from each of the output circuits ( (2 or more) Since the multi-selection circuit for determining the output when the condition is satisfied is provided, the reliability of the output circuit is improved.

Further, the plant control apparatus according to the present invention is provided with four output circuits, and the multiple selection circuit is an amplifier circuit for operating three contacts with the output signal for each of the output circuits; The output logic circuit includes a determination logic circuit that determines the output when a plurality (2 or more) of the output signals from each of the output circuits are established by a total of 12 contacts of the output circuit, so that the redundancy of the output circuit can be easily and reliably realized. At the same time, even in the case of one failure of the output circuit, it is possible to make an output determination based on a plurality of outputs.

Further, the plant control apparatus according to the present invention includes an answerback circuit for individually discriminating each output signal of the plurality of output circuits, and operates the answerback circuit in serial with the control operation timing of the plant. As a result, the presence or absence of an abnormality in each of the output circuits is constantly monitored, so that the presence or absence of an abnormality in each of the output circuits can be reliably grasped, and the reliability is further improved.

Further, in the plant control apparatus according to the present invention, when four output circuits are provided, when an abnormality of one output circuit is detected, the remaining three circuits except the abnormal output circuit are detected.
A selection processing unit for selecting the output circuit so as to make an output determination based on a plurality of outputs based on output signals from the plurality of output circuits; A highly reliable operation based on the determination can be maintained.

Further, the plant control apparatus according to the present invention comprises an equipment signal generation circuit for generating an equipment selection signal output when selecting a predetermined equipment in the plant and an equipment output signal output when driving the equipment. And a plant control device having an output circuit that converts the device signal into a relay signal required to drive the plant device, wherein the amplifier circuit operates a contact with the output signal for each output circuit, and Since a judgment logic circuit is provided for judging an output when a logical product of the output signals from the respective output circuits is established by a contact, an erroneous operation of the device can be prevented,
Operational reliability is improved.

Further, the plant control apparatus according to the present invention includes an equipment signal generation circuit and an output circuit for the service system and the standby system, respectively, and the determination logic circuit determines the logical product of the output signals in the service system and the standby system. Since the output is determined when the logical sum of the logical product of the output signal and the logical product is satisfied, the switching between the service system and the standby system is smoothly performed.

Further, a plant control device according to the present invention provides a control circuit for creating a control logic signal for controlling a plant, and a control logic signal from the control circuit for driving equipment in the plant. In a plant control device provided with an output circuit for converting to a relay signal,
In the process of replacing the control circuit and output circuit,
When the existing system to be removed and the newly installed update system coexist, an amplification circuit that operates a contact with the output signal for each output circuit of the two systems, and a logical sum of the output signals from each of the output circuits by the contact By providing a determination logic circuit that determines the output when the condition is satisfied, the downtime of the plant associated with the replacement work can be shortened. Can be shortened.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a plant control device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing details of a controller part of FIG. 1;

FIG. 3 is a diagram illustrating details of a portion of a multiple selection circuit in FIG. 1;

FIG. 4 is a circuit diagram for explaining the operation principle of the determination logic circuit of FIG. 3;

FIG. 5 is a specific circuit configuration diagram of the first embodiment.

FIG. 6 is a front view showing the outer shape of FIG. 5;

FIG. 7 is a side view showing the outer shape of FIG. 5;

FIG. 8 is a diagram showing a flow of an abnormality check according to the second embodiment of the present invention.

FIG. 9 is a diagram showing a flow of an operation for selecting an output pattern according to Embodiment 3 of the present invention.

FIG. 10 is a diagram showing a logic circuit for performing the operation of step S101 in FIG. 9;

FIG. 11 is a diagram showing a logic circuit for performing an operation according to a fourth embodiment of the present invention.

FIG. 12 is a diagram illustrating a configuration of a plant control device according to a fifth embodiment of the present invention.

FIG. 13 is a diagram illustrating a configuration of a plant control device according to a sixth embodiment of the present invention.

FIG. 14 is a diagram showing a configuration of a plant control device according to a seventh embodiment of the present invention.

FIG. 15 is a diagram showing a configuration of a plant control device according to a seventh embodiment of the present invention.

FIG. 16 is a diagram illustrating a state of an existing system for explaining a plant control device according to an eighth embodiment of the present invention.

FIG. 17 is a diagram illustrating a state of an existing system for describing a plant control device according to an eighth embodiment of the present invention.

FIG. 18 is a diagram illustrating a state when an existing / updated system coexists with the plant control device according to Embodiment 8 of the present invention.

FIG. 19 is a diagram illustrating a state of an update system for explaining a plant control device according to an eighth embodiment of the present invention.

FIG. 20 is a diagram illustrating a configuration of a plant control device according to an eighth embodiment.

FIG. 21 is a diagram showing a configuration of a conventional plant control device.

[Explanation of symbols]

10 plant, 11 controller, 12 multiple selection circuit, 14 output circuit, 16 actuator, 120
Decision logic circuit, 140 digital signal output device,
142 amplification circuit, 143 amplification contact, 144 OR circuit, 145 OR circuit, 146 AND circuit, 147
OR circuit.

Claims (7)

[Claims] 1. A control circuit for generating a control logic signal for controlling a plant, and an output circuit for converting the control logic signal from the control circuit into a relay signal required for driving equipment in the plant. A plurality of (three or more) output circuits having a common input side.
A plurality of (two or more) output signals from each of the above output circuits
A plant control device comprising a multiple selection circuit that determines an output when the condition is satisfied. 2. A multi-selector circuit comprising: four output circuits; an amplifier circuit for operating three contacts with output signals of each of the output circuits; and a total of twelve output circuits of the four output circuits.
2. The plant control device according to claim 1, further comprising a determination logic circuit that determines an output when a plurality of (two or more) output signals from each of the output circuits are established by a plurality of contacts. 3. An answerback circuit for individually discriminating each output signal of a plurality of output circuits, and operating the answerback circuit serially with a timing of a control operation of a plant to determine whether each of the output circuits is abnormal. 3. The method according to claim 1, wherein the monitoring is constantly performed.
3. The plant control device according to 1. 4. When four output circuits are provided, when an abnormality is detected in one output circuit, a plurality of outputs are established based on output signals from the remaining three output circuits excluding the abnormal output circuit. 4. The plant control device according to claim 3, further comprising a selection processing unit that selects the output circuit so as to make a determination. 5. An equipment signal generating circuit for generating an equipment selection signal output when selecting a predetermined equipment in a plant and an equipment output signal output when driving the equipment, In a plant control device provided with an output circuit for converting a relay signal necessary for driving a device, an amplifier circuit for operating a contact with the output signal for each of the output circuits, and an output from each of the output circuits by the contact A plant control device comprising: a determination logic circuit that determines an output when a logical product of signals is satisfied. 6. An apparatus signal generating circuit and an output circuit are provided for a service system and a standby system, respectively, and a determination logic circuit is configured to determine a logical product of an output signal of the service system and a logical product of an output signal of the standby system. The plant control device according to claim 5, wherein the output is determined when the sum is satisfied. 7. A control circuit for generating a control logic signal for controlling a plant, and an output circuit for converting the control logic signal from the control circuit into a relay signal required for driving a device in the plant. In the plant control device provided, in the process of replacing the control circuit and the output circuit,
When the existing system to be removed and the newly installed update system coexist, an amplification circuit that operates a contact with the output signal for each output circuit of the two systems, and a logical sum of the output signals from each of the output circuits by the contact A plant control device comprising a determination logic circuit for determining an output when the condition is satisfied, thereby enabling a reduction in a plant stoppage period accompanying the replacement work.