JP2001195104A - Interlock circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain cost reduction, space saving and reduction of maintenance/ inspection work by constituting a storage circuit 6-2 in a control device 3 as a circuit based on software as compared with a conventional circuit based on hard-wired processing and to prevent a start signal from being falsely outputted due to the release of the locked state of the storage circuit 6-2 when the control device 3 is started. SOLUTION: When an operation lock command is outputted form an operation frame 1, the storage circuit 6-2 stores the locked state so that a start signal 8 is not outputted from an AND circuit 22. When the control device 3 stopped duet to maintenance/inspection or the like is started, the storage circuit 6-2 is turned to an unlocked state by clearing the initialized locked state. Since another monitoring storage circuit 6-1 stores the locked state, signal comparing/deciding circuit 9 compares outputs from both the storage circuits 6-1, 6-2, and when these outputs are different from each other, displays an alarm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an interlock circuit, and more particularly, to an interlock circuit that blocks a start operation output to a target device, which is required when inspecting a plant device.

[0002]

2. Description of the Related Art Hitherto, an interlock for blocking a start command output from a control device to plant equipment has been configured by hard-wired processing (a logic circuit is configured by a relay and a connection wiring of the relay). In FIG. 5, reference numeral 1 denotes an operation frame for operating plant equipment, and operations such as activation, operation lock, and release are performed by touch operations on a screen.
2 is a C for transmitting an operation on the operation frame 1 to the control device.
The RT operation device is configured to operate by software with a built-in CPU. The CRT screen includes the screen of the operation frame 1 and displays plant status, equipment, circuits, and the like on the screen and various types of operation. Perform control operations.

Reference numeral 3 denotes a control device for operating and controlling the plant equipment, 4 denotes a start command output from the control device for the plant equipment, 5 denotes an auxiliary relay panel which comprises an interlock by hard-wired processing, and 6 denotes an auxiliary relay panel. A storage circuit that holds a state of the operation lock that is configured, a plant device 7 that is operated and controlled by the control device 3, and a start signal 8 that drives the plant device 7.

Next, the operation will be described. (1) The operation lock is operated on the operation frame 1 and this operation signal is transmitted to the control device 3 via the CRT operation device 2. (2) The control device 3 outputs the operation lock signal to the auxiliary relay panel 5, and the storage circuit 6 configured by the auxiliary relay panel 5
Holds the locked state. (3) In this state, if a manual start command is satisfied when an operator erroneously performs a start operation on the operation frame 1 or an automatic start command from the control device is satisfied, a start command output 4 from the control device 3 is issued. Is output to the auxiliary relay panel 5.

(4) The storage circuit 6 in the auxiliary relay panel 5
Is locked by the AND circuit 22 via the NOT circuit 21. (5) The activation signal 8 is not established because the locked state signal is established, and the plant equipment 7 is not driven even when the operator performs an erroneous operation or the automatic activation command is established (operation locked state). As a result, security of the plant equipment can be secured.

[0006]

Since the conventional interlock circuit is constructed as described above, in a large-scale plant such as a thermal power plant, the operation lock storage circuit 6 for hundreds of plant equipment is used. Must be hard-wired, and the number of auxiliary relay boards 5 for storing the same increases, so that the cost increases and a large installation space is required. In recent years, there has been a problem that thermal power plants tend to operate with a small number of people, and it is difficult to perform maintenance and inspection work on a huge storage circuit 6 by hard-wired processing.

In order to solve the above-mentioned problem, in the present invention, the storage circuit 6 is made into software by using a calculation function (built-in CPU). In addition, there is a problem that when the state should be the locked state, the locked state is released and a start signal is output.

[0008] Japanese Patent Publication No. 61-7641 is a reference technique for reducing the number of auxiliary relay panels, reducing the installation space, and simplifying the maintenance and inspection work. As shown, the AND circuit 1 in the computer 8
There are software logics such as 6, 17 and the like, which are interlocked by an interlock signal C. However, in the case of starting the control device such as the present invention, when the software logic is in a state where it should be locked, the locked state is released and a start signal is output. Did not touch.

The present invention has been made in order to solve the above-mentioned problems, and by making the operation lock storage circuit 6 into software, it can be manufactured at low cost.
In addition, the installation of the auxiliary relay panel saves space, eliminates the maintenance and inspection work of the storage circuit, and the state in which the softwareized storage circuit should be locked when the auxiliary relay panel is started up. It is an object of the present invention to obtain an interlock circuit in which the locked state is not released at the time.

[0010]

An interlock circuit according to the present invention stores a locked state or an unlocked state in response to a locking operation or an unlocking operation, and
A first storage circuit for outputting a lock signal in accordance with the storage result, a lock circuit for locking or unlocking a control signal for controlling plant equipment or the like in accordance with the presence or absence of the lock signal, a lock operation or an unlock operation A second storage circuit that stores a lock state or an unlocked state according to the stored result and outputs a monitor signal according to the storage result, and compares the monitor signal with the output of the first storage circuit. If there is a mismatch, an alarm signal is transmitted, or a malfunction prevention means for forcibly locking the control signal is provided,
At least the first storage means is processed by software.

A means for forcibly locking the control signal is provided at least during a period in which the first storage circuit is initialized by software.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. In FIG.
Reference numeral 1 denotes an operation frame for operating plant equipment. Operations such as activation, operation lock, and release are performed by touch operations on the screen. Reference numeral 2 denotes a CRT operation device which transmits an operation on the operation frame 1 to the control device 3 and is configured to operate by software with a built-in CPU. The CRT screen includes the screen of the operation frame 1 described above. The above displays the status, equipment, circuits, etc. of the plant and performs various control operations.

Reference numeral 3 denotes a control device for controlling the operation of the plant equipment, which has a built-in CPU and is operated by software. 6-1 is a storage circuit for holding the operation lock state for the monitor formed in the CRT operation device 2, 6-2 is a storage circuit for holding the operation lock state formed in the control panel 3, and 7 is the control circuit 3 The operation-controlled plant equipment 8 is a start signal from the control device 3 for driving the plant equipment 7. When the capacity of the plant equipment is large, a relay may be provided between the plant equipment and the start signal. Reference numeral 9 denotes a signal comparison / determination circuit for the storage circuits 6-1 and 6-2 included in the CRT operation device 2. 20 is O
An R circuit, 21 is a NOT circuit, and 22 is an AND circuit.

Next, the operation will be described. (1) The operation lock is operated on the operation frame 1 and the operation signal is stored in the storage circuit 6 in the CRT operation device 2.
At −1, it is transmitted to the control device 3. (2) The control device 3 holds the locked state in the internal storage circuit 6-2, and returns this state signal to the CRT operation device 2.

(3) In this state, if the operator erroneously performs a start operation on the operation frame 1, a manual start command is satisfied, or an automatic start command from the control device is satisfied, and the OR circuit 20 is activated. Output. (4) On the other hand, since the NOT circuit 21 and the AND circuit 22 do not output due to the lock state signal held in the storage circuit 6-2 in the control device 3, the OR circuit 2
The output of 0 is blocked, and the start signal 8 is not output. Therefore, the plant equipment 7 is not driven even when the operator performs an erroneous operation or the automatic start command is established (operation locked state). As a result, security of the plant equipment can be secured.

Next, a description will be given of a time when the control device 3 is restarted upon inspection. When the control device 3 is restarted upon inspection, the state of the storage circuit 6-2 is cleared by initialization. If the operation circuit is locked before the initialization, the locked state is cleared by initialization (locked state). Is released), and before initialization, the control device 3 operates its internal storage circuit 6-2.
Unlock state in CRT operation device 2
Since the monitor storage circuit 6-1 holds the locked state, the signal comparison determination circuit 9 determines that there is no match, and displays an alarm on the operation frame 1.

The warning display alerts the operator, performs the operation lock operation again on the operation frame 1, resets the operation lock in the storage circuit 6-2 of the control device 3, and performs the operation before the initialization. The locked state can be restored. Therefore, even if the operation lock storage circuit 6-2 is made into software, a highly reliable device equivalent to hard wired processing can be obtained.

Embodiment 2 FIG. In the first embodiment, if the operation lock state before the initialization has been cleared by the initialization at the time of the restart of the control device 3 at the time of the inspection,
The signal comparison / determination circuit 9 in the CRT operation device 2 determines that they do not match, and displays an alarm on the operation frame 1 to call attention of the operator and re-operate the operation frame 1.
The operation lock operation is performed in, the operation lock is reset in the control device 3 and the operation lock state before the initialization is restored, so that even if the operation lock storage circuit 6-2 is made into software, the hard-wired processing can be performed. The case where an equivalent highly reliable device can be obtained has been described.

In the second embodiment, when the signal comparison / judgment circuit 9 judges that they do not coincide with each other, forcible locking is performed instead of displaying an alarm. As shown in FIG.
An OR circuit 10 is provided inside the operation device 2, and when a mismatch is determined by the signal comparison determination circuit 9, an operation lock signal is automatically transmitted to the control device 3. Then, the operation lock is reset and the operation lock state before the initialization is restored. This eliminates the need for re-operation by the operator, thereby reducing the burden.

Embodiment 3 In the second embodiment, when the operation lock state before the initialization has been cleared by the initialization at the time of the restart of the control device 3 at the time of the inspection,
An OR circuit 10 is provided inside the CRT operation device 2, and when a mismatch is determined by the signal comparison / determination circuit 9, an operation lock signal is automatically transmitted to the control device 3, the operation lock is reset, and the operation before initialization is performed. The case where the locked state is restored and the burden on the operator can be reduced by eliminating the re-operation of the operator is described.

In the third embodiment, when the control device 3 is restarted upon inspection, the start signal is forcibly locked during initialization. As shown in FIG. 3, a storage circuit 1 that holds a state of being initialized inside a control device 3
1. AND circuit 1 inside CRT operation device 2
2. A means for transmitting the operation lock reset completion 13 to the control device 3 is provided.

Since the timing for automatically transmitting the operation lock signal from the CRT operation device 2 to the control device 3 is limited to the "state in which the control device 3 is being initialized", the resetting of the operation lock is originally required. The logic can be operated only when necessary, and the reliability of the automatically transmitted lock signal itself can be increased by this conditioning.

Although the internal circuit of the CRT operation device 2 is also softwareized and is sometimes initialized, it is not initialized at the same time as the control device 3. Since a plurality of units are provided via a network and share internal data, even if any CRT operation device 2 is initialized, the other CRT operation devices 2 are operating, so that the stored contents are not erased. Absent.

Embodiment 4 In the third embodiment, the storage circuit 1 that holds the state of being initialized inside the control device 3
1. AND circuit 1 inside CRT operation device 2
2. A means 13 for transmitting the operation lock reset completion to the control device 3 is provided, and the timing of automatically transmitting the operation lock signal from the CRT operation device 2 to the control device 3 is set when the control device 3 is in the initializing state. As described above, the logic can be operated only when the resetting of the operation lock is originally required, and the reliability of the lock signal itself automatically transmitted by this condition can be improved. .

In the fourth embodiment, in the case of the third embodiment, the lock during initialization is made more reliable. As shown in FIG. 4, a NOT circuit 14 is further provided inside the control device 3 in addition to the circuit of FIG.
The output of the T circuit 14 is input to the AND circuit 22. The lock state of the storage circuit 11 remains established until the signal of the reset completion 13 of the operation lock is output, so that the activation signal 8 can be made unsatisfied.

Therefore, even if the operator performs an erroneous operation or the automatic start command is established until the resetting of the operation lock is completed (usually, it can be assumed to be several seconds), the plant equipment 7 is not required. Is not driven (operation lock state),
Reliability can be further improved. The signal indicating that the operation lock has been reset 13 to the control device is output as a kick when, for example, there is no device in which the lock state is different in the signal comparison determination circuit 9.

[0027]

As described above, according to the present invention, the first storage circuit is made into software to reduce the cost, save space, and reduce maintenance work, and unnecessary lock by the first storage circuit. This prevents the state from being released and contributes to the safe operation of the plant.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of an interlock circuit according to a first embodiment of the present invention.

FIG. 2 is a circuit diagram of an interlock circuit according to a second embodiment of the present invention.

FIG. 3 is a circuit diagram of an interlock circuit according to a third embodiment of the present invention.

FIG. 4 is a circuit diagram of an interlock circuit according to a fourth embodiment of the present invention.

FIG. 5 is a circuit diagram of a conventional interlock circuit.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 operation frame 2 CRT operation device 3 control device 6-1 storage circuit (second storage circuit) 6-2 storage circuit (first storage circuit) 7 plant equipment 8 start signal 9 signal comparison / determination circuit 10, 20 OR circuit 11 Memory circuit 12, 22 AND circuit 13 Operation lock reset to controller 3 completed 14, 21 NOT circuit

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[Procedure amendment]

[Submission date] March 2, 2000 (200.3.2)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction contents]

The present invention has been made in order to solve the above-mentioned problems, and by making the operation lock storage circuit 6 into software, it can be manufactured at low cost.
In addition, the installation of the auxiliary relay panel saves space, eliminates the maintenance and inspection work of the storage circuit, and makes it possible to lock the software storage circuit when the control device is started up. An object of the present invention is to provide an interlock circuit in which the locked state is not released sometimes.

Claims (2)

[Claims] 1. A lock state or an unlock state is stored according to a lock operation or a lock release operation, and
A first storage circuit for outputting a lock signal in accordance with the storage result, a lock circuit for locking or unlocking a control signal for controlling plant equipment or the like in accordance with the presence or absence of the lock signal, a lock operation or an unlock operation A second storage circuit that stores a lock state or an unlocked state according to the stored result and outputs a monitor signal according to the storage result, and compares the monitor signal with the output of the first storage circuit. If there is a mismatch, an alarm signal is transmitted, or a malfunction prevention means for forcibly locking the control signal is provided,
An interlock circuit wherein at least the first storage means is processed by software. 2. The interlock circuit according to claim 1, wherein means for forcibly locking the control signal is provided at least during a period in which the first storage circuit is initialized by software.