Safety instrumentation system and plant safety system

An instruction converting unit converts the data form of an instruction of an operation received by a receiving unit to the data form of a safety instrumentation system from the data form of a plant control system. An operation carrying out unit receives the instruction of the operation obtained by the instruction converting unit and an original instruction of the safety instrumentation system to carry out the operations, and preferentially carries out the operation of the original instruction of the safety instrumentation system when both the instructions compete with each other.

This application claims priority to Japanese Patent Application No. 2006-217653, filed Aug. 10, 2006, in the Japanese Patent Office. The priority application is incorporated by reference in its entirety.

TECHNICAL FIELD

The present disclosure relates to a safety instrumentation system connected to a plant control system, and a plant safety system including the safety instrumentation system and the plant control system, and more particularly to a safety instrumentation system that can construct a unified environment.

RELATED ART

A safety instrumentation system aiming to ensure the safety of a plant has been known. The safety instrumentation system is provided as a separate system independent of the plant control system for controlling the field device of the plant so that the safety instrumentation system can assuredly operate to ensure a safety.

On the other hand, in order to improve operability, a technique for uniting the plant control system with the safety instrumentation system has been developed. In order to unite these systems with each other, both the systems are connected together by a common communication line to achieve a communication between the systems.FIG. 4shows the structure of such a united system and a safety instrumentation system110and a distributed control system120are connected together through a communication line30. In the safety instrumentation system110, a safety control station101is provided for carrying out a process to realize the safety of a plant. To the safety control station101, valves4are connected through an input and output device3. Further, in the distributed control system120, a monitor station107is provided for monitoring field controllers6for controlling field devices and the entire part of the plant.

The united structure of the safety instrumentation system and the control system is disclosed in, for instance, Japanese Patent Unexamined Publication No. 2006-164143.

As shown inFIG. 4, when the distributed control system120and the safety instrumentation system110are connected to each other, the device of the safety instrumentation system110can be operated from the monitor station107of the distributed control system120. For instance, the field controller6for originally controlling the field device may be possibly assigned to the operation of the device of the safety instrumentation system. In such a method, data of the valve4treated in the safety control station101of the safety instrumentation system110is coordinated with data treated in the field controller6. Further, a communication function between the safety control station101and the field controller6is added. Therefore, the device such as the valve4of the safety instrumentation system110can be operated from the monitor station107in the same method as that of the operation to the field device.

However, it requires a troublesome operation to coordinate the data of the safety control station101with the data of the filed controller6. Thus, this operation imposes a burden on engineering. Further, the contents of the operation or the monitor to the device of the safety instrumentation system are restricted by the original function of the field controller6. For instance, whether or not the contents of the operation are properly reflected on the state of the device cannot be recognized. Further, it is difficult to construct an arrangement for ensuring the assuredness and safety of an operation to be required for the safety instrumentation system110.

SUMMARY

Exemplary embodiments of the present invention provide a safety instrumentation system that can operate a device of a safety instrumentation system side through a plant control system by suppressing a burden of engineering, and a plant safety system including the safety instrumentation system and the plant control system.

A safety instrumentation system of one or more embodiments of the present invention is connected to a plant control system. One or more embodiments of the safety instrumentation system comprises: a receiving unit that receives an instruction of an operation to a device of the safety instrumentation system through an instruction receiving part for receiving an instruction of an operation to a field device of the plant control system; an instruction converting unit that converts the data form of the instruction of the operation received by the receiving unit to the data form of the safety instrumentation system from the data form of the plant control system so that the instruction received by the receiving unit can be used as the instruction of the operation to the device of the safety instrumentation system; and an operation carrying out unit that receives the instruction of the operation obtained from the instruction converting unit and an original instruction of the safety instrumentation system to carry out the operations, and preferentially carries out the operation of the original instruction of the safety instrumentation system when both the instructions compete with each other, and is characterized in that the instruction converting unit and the operation carrying out unit are formed by using a function block mounted on the safety instrumentation system.

According to this safety instrumentation system, since the instruction converting unit and the operation carrying out unit are formed by using the function block mounted on the safety instrumentation system, the burden of engineering can be suppressed.

When the instruction of the operation is received by the receiving unit, a certifying unit may be provided that certifies a user.

The safety instrumentation system of the present invention may include a display unit that displays, in the plant control system, the state of the field device of the plant control system; and a state converting unit that converts the data form of data showing the state of the device of the safety instrumentation system to the data form of the plant control system from the data form of the safety instrumentation system so that the state of the device of the safety instrumentation system can be displayed by the display unit.

The device of the safety instrumentation system may be a valve that carries out a shut down in a plant.

One or more embodiments of the present invention may include one or more the following advantages. For example, since the instruction converting unit and the operation carrying out unit are formed by using a function block mounted on the safety instrumentation system, the burden of engineering can be suppressed.

Other features and advantages may be apparent from the following detailed description, the accompanying drawings and the claims.

DETAILED DESCRIPTION

Now, referring toFIGS. 1 to 3, an exemplary embodiment of a safety instrumentation system according to the present invention will be described below.

FIG. 1is a block diagram showing a structure of a safety instrumentation system of an exemplary embodiment.

As shown inFIG. 1, the safety instrumentation system10of the exemplary embodiment is connected to a distributed control system20through a communication line30.

The distributed control system20includes field controllers6,6, . . . distributed and arranged in a plant for controlling field devices5,5, . . . , a monitor station7for monitoring and controlling the field devices5,5, . . . through the field controllers6,6. . . , and a terminal device8for maintenance for maintaining and managing the distributed control system20. The filed controllers6,6, . . . , the monitor station7and the terminal device8for maintenance are connected together through the communication line30.

In the monitor station7, operation output values MV to the field devices5,5. . . , and process values PV to the field devices5,5. . . are displayed. Further, the monitor station7functions as an instruction receiving part for receiving an instruction of an operation to the field devices5,5. . . .

The safety instrumentation system10includes a safety control station1for carrying out a process for maintaining the safety of the plant and a terminal device2for maintenance for maintaining and managing the safety instrumentation system10. The safety control station1and the terminal device2for maintenance are connected to each other through the communication line30.

Further, the safety control station1is connected to a group of limit switches or valves4,4, . . . through an input and output device3.

As shown inFIG. 1, the monitor station7of the distributed control system20includes a receiving unit71for receiving an instruction of an operation to the devices of the plant safety instrumentation system and a display unit72for displaying the states of the field devices5,5, . . . of the plant control system20.

Further, the safety control station1of the safety instrumentation system10includes an instruction converting unit11; an operation carrying out unit12; a certifying unit13; and a state converting unit14. The instruction converting unit11converts the data form of the instruction of the operation received by the receiving unit71to the data form of the safety instrumentation system10from the data form of the plant control system20so that the instruction received by the receiving unit71can be used as the instruction of the operation to the device of the safety instrumentation system10. The operation carrying out unit12receives the instruction of the operation obtained by the instruction converting unit11and an original instruction of the safety instrumentation system10to carry out the operations, and preferentially carries out the operation of the original instruction of the safety instrumentation system10when both the instructions compete with each other. The certifying unit13certifies a user when the instruction of the operation is received by the receiving unit71. The state converting unit14converts the data form of data showing the state of the device of the safety instrumentation system10to the data form of the plant control system20from the data form of the safety instrumentation system10so that the state of the device of the safety instrumentation system10can be displayed by the display unit72.

FIG. 2is a diagram showing a function block and a map block mounted on the safety control station1. As shown inFIG. 2, in the safety control station1, a Boolean type manual operation function block21and a map block22are mounted relative to the various kinds of devices such as the valve4.

In the function block21, an operating procedure is defined that is related to a manual operation for the device of the safety instrumentation system. The instruction converting unit11and the operation carrying out unit12are formed by using the function block21. InFIG. 2, a part of input and output elements of the function block21is omitted.

As shown inFIG. 2, to a shut down input terminal (SHDN) of the function block21, a signal from a shut down logic mounted on the safety control station1is inputted.

A detecting signal of a limit switch for detecting the opening state of the valve4of the safety instrumentation system10is fetched as an input variable (ANSVAR1) of the safety control station1through the input and output device3. The input variable (ANSVAR1) is inputted to an answer back input terminal (AINP) of the function block21.

A detecting signal of a limit switch for detecting the closing state of the valve4of the safety instrumentation system10is fetched as an input variable (ANSVAR2) of the safety control station1through the input and output device3. The input variable (ANSVAR2) is inputted to an answer back input terminal (AINM) of the function block21.

An output terminal (OUT) of the function block21is connected to an output variable (OPVAR) supplied to the valve4.

To the map block22, parameters of the function block21are respectively transferred.

The parameters of the map block22are supplied to the monitor station7of the distributed control system20through the communication line30and displayed on a monitor screen as a face plate40shown inFIG. 2by the display unit72. Further, an operation to the faceplate40is supplied to the map block22through the receiving unit71and the communication line30and reflected on the parameters. The structure of the face plate40is the same as the structure of a faceplate for operating and monitoring the field device5of the distributed control system20, so that an operator can operate the device of the safety instrumentation system with the same sense as that of an operation to the field device5.

As shown inFIG. 2, in the face plate40, a display area41of a tag name corresponding to the valve4, a display area42of a process value (PV) and an operation output value (MV) of the valve4, buttons43aand43bfor displaying the process value (PV) and buttons44aand44bfor receiving the input of the operation output value (MV) are provided.

Now, an operation carried out when the valve4of the safety instrumentation system10is operated by using the face plate40will be described below.

The operator can change the operation output value (MV) by operating the button44aor44b. The operation of the operator is reflected on the contents of the display of the display area42. The operation for changing the operation output value (MV) is supplied to the safety control station1through the receiving unit71and the communication line30to instruct the map block22to change the operation output value (MV). When the operation output value (MV) of the map block22is changed, the changed value is transferred to the output variable (OPVAR) outputted from the output terminal (OUT) of the function block21. The output variable (OPVAR) is outputted to the valve4through the input and output device3.

The opening/closing state of the valve4is fetched to the function block21as the input variable (ANSVAR1) or the input variable (ANSVAR2) based on the detecting signal of the limit switch and converted to the process value (PV). The process value (PV) of the function block21is reflected on the map block22and supplied to the monitor station7of the distributed control system20through the communication line30. The display unit72reflects the supplied process value (PV) on a display in the display area42and the buttons43aand43bof the face plate40.

Accordingly, the operator compares the operation output value (MV) with the process value (PV) displayed on the face plate40so that the operator can recognize whether or not the operation to the operation output value (MV) is properly transmitted to the valve4to be operated.

In the safety instrumentation system of the exemplary embodiment, the function block21outputs the output variable (OPVAR) determined by the application software of the safety instrumentation system from the output terminal (OUT) preferentially to the operation to the operation output value (MV) through the face plate40. When the signal inputted to the shut down input terminal (SHDN) of the function block21corresponds to a specific condition, a shut down output value is outputted from the output terminal (OUT) irrespective of the operation by the face plate40.

Accordingly, for instance, even when an operation of the safety instrumentation system is temporarily released to operate the valve4during starting or maintaining the plant, if a new shut down phenomenon arises, the operation to the face plate40is neglected to assuredly shut down the plant. Therefore, when the device of the safety instrumentation system is manually operated, an unexpected situation can be avoided.

Further, in the safety instrumentation system of the exemplary embodiment, during the operation of the operation output value (MV) through the face plate40, the operator is certified by the certifying unit13. During the operation of the operation output value (MV), the operator is requested to input a password and the inputted password is supplied to the safety control station1through the communication line30.

The inputted password is collated with a password of a password input terminal (PSWD) of the function block21. Only when the passwords correspond to each other, the function block21receives the change of the operation output value (MV). Thus, a right for operating the valve4can be given only to a specific person.

As described above, according to the safety instrumentation system of the exemplary embodiment, the device of the safety instrumentation system10can be operated through the monitor station7of the distributed control system20like the field device5of the distributed control system20. Further, an algorithm for realizing the above-described operation is described by the function block of the safety instrumentation system10side. Accordingly, a description by the application software of the distributed control system20side is not required, so that an engineering cost and an engineering burden can be extremely suppressed.

FIG. 3is a diagram showing a function block and a map block when an analog valve is used as a device of the safety instrumentation system. As shown inFIG. 3, in the safety control station1, an analog type manual operation function block21A and a map block22A are respectively mounted relative to analog valves.

In the function block21A, an operating procedure is defined that is related to a manual operation for the analog valve. The instruction converting unit11and the operation carrying out unit12are formed by using the function block21A. InFIG. 3, a part of input and output elements of the function block21A is omitted.

As shown inFIG. 3, to a shut down input terminal (SHDN) of the function block21A, a signal from a shut down logic mounted on the safety control station1is inputted.

A signal of an aperture sensor of the analog valve is fetched as an input variable (FVVAR1) through the input and output device3. The input variable (FVVAR1) is inputted to a feedback input terminal (FV) of the function block21A.

An output terminal (OUT) of the function block21A is connected to an output variable (OPVAR) supplied to the analog valve.

To the map block22A, parameters of the function block21A are respectively transferred.

The parameters of the map block22A are supplied to the monitor station7of the distributed control system20through the communication line30and displayed on a monitor screen as a face plate50shown inFIG. 3by the display unit72. Further, an operation to the face plate50is supplied to the map block22A through the receiving unit71and the communication line30and reflected on the parameters. The structure of the face plate50is the same as the structure of a faceplate for operating and monitoring the field device5of the distributed control system20, so that an operator can operate the device of the safety instrumentation system with the same sense as that of an operation to the field device5.

As shown inFIG. 3, in the face plate50, a display area51of a tag name corresponding to the analog valve, a display area52of a feedback value (FV) showing the opening degree of the analog valve and an operation output value (MV), an area53for displaying the feedback value (FV) and an area54for receiving an input of the operation output value (MV) are provided.

Now, an operation carried out when the analog valve of the safety instrumentation system is operated by using the face plate50will be described below.

An operator can change the operation output value (MV) by operating the area54. The operation of the operator is reflected on the contents of the display of the display area52. The operation for changing the operation output value (MV) is supplied to the safety control station1through the receiving unit71and the communication line30to instruct the map block22A to change the operation output value (MV). When the operation output value (MV) of the map block22A is changed, the changed value is transferred to the output variable (OPVAR) outputted from the output terminal (OUT) of the function block21A. The output variable (OPVAR) is outputted to the analog valve through the input and output device3.

The opening degree or aperture of the analog valve is fetched to the function block21A as the input variable (FVVAR1) and reflected on the feedback value (FV). The feedback value (FV) of the function block21A is reflected on the map block22A and supplied to the monitor station7of the distributed control system20through the communication line30. The display unit72reflects the supplied feedback value (FV) on a display in the display area52and the display area53of the face plate50.

Accordingly, the operator compares the operation output value (MV) with the feedback value (FV) displayed on the face plate50so that the operator can recognize whether or not the operation to the operation output value (MV) is properly transmitted to the analog valve to be operated.

In the safety instrumentation system of the exemplary embodiment, the function block21A outputs the output variable (OPVAR) determined by the application software of the safety instrumentation system from the output terminal (OUT) preferentially to the operation to the operation output value (MV) through the face plate50. When the signal inputted to the shut down input terminal (SHDN) of the function block21A corresponds to a specific condition, a shut down output value is outputted from the output terminal (OUT) irrespective of the operation by the face plate50.

Accordingly, for instance, even when an operation of the safety instrumentation system is temporarily released to operate the analog valve during starting or maintaining the plant, if a new shut down phenomenon arises, the operation to the face plate50is neglected to assuredly shut down the plant. Therefore, when the device of the safety instrumentation system is manually operated, an unexpected situation can be avoided.

Further, in the safety instrumentation system of the exemplary embodiment, during the operation of the operation output value (MV) through the face plate50, the operator is certified by the certifying unit13. During the operation of the operation output value (MV), the operator is requested to input a password and the inputted password is supplied to the safety control station1through the communication line30.

The inputted password is collated with a password of a password input terminal (PSWD) of the function block21A. Only when the passwords correspond to each other, the function block21A receives the change of the operation output value (MV). Thus, a right for operating the analog valve can be given only to a specific person.

As described above, the analog valve of the safety instrumentation system can be operated through the monitor station7of the distributed control system20like the field device5of the distributed control system20. Further, an algorithm for realizing the above-described operation is described by the function block of the safety instrumentation system side. Accordingly, a description by the application software of the distributed control system20side is not required, so that an engineering cost and an engineering burden can be extremely suppressed.

An applied range of the present invention is not limited to the above-described exemplary embodiment. The present invention can be widely applied to the safety instrumentation system connected to the plant control system.

While the present invention has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope of the present invention as disclosed herein. Accordingly, the scope of the present invention should be limited only by the attached claims.