Patent ID: 12253847

DESCRIPTION OF EMBODIMENTS

Hereinafter, an embodiment of the present disclosure will be described in detail with reference to drawings. However, when figures such as the number, quantity, volume, or range of elements are referred to in the embodiment presented below, the present disclosure is not limited by the figures referred to except where especially explicitly specified and where clearly specified to the figures in principle. In addition, structures and the like that are described in the embodiment presented below are not necessarily required for this disclosure except where especially explicitly specified and where clearly specified thereto in principle. Note that common elements in the drawings are denoted by the same reference signs and thus redundant explanations thereof will be omitted.

First Embodiment

FIG.1andFIG.2are diagrams for describing a configuration of a plant monitoring and control system according to a first embodiment of the present disclosure.

The plant monitoring and control system includes a monitoring device1, a control network HUB4, a human machine interface (HMI) server5, a programmable logic controller (PLC)6, an I/O device7, a field network HUB8, a drive device9, and a plurality of field devices10. The monitoring device1includes an HMI client2and a hardware switch3.

A connection relation between the devices will be described with reference toFIG.1. The HMI client2is connected to the HMI server5via a control network HUB4. The hardware switch3is connected to the PLC6via the I/O device7and the field network HUB8. The HMI server5is connected to the PLC6via the control network HUB4. The drive device9is connected to the PLC6via the field network HUB8. The plurality of field devices10are connected to the drive device9.

As illustrated inFIG.2, the PLC6is electrically connected to the hardware switch3, an HMI subsystem30, the plurality of field devices10. The HMI subsystem30includes the HMI client2and the HMI server5.

With reference toFIG.2, the hardware switch3, the HMI subsystem30(HMI client2, HMI server5), and the PLC6will be described. Especially, a relationship between a general-purpose operation part, the field devices10and the hardware switch3will be described.

(Hardware Switch3)

The hardware switch3outputs, when operated by an operator, a control signal for controlling each of the field devices10that constitutes an industrial plant. The field devices10are actuators such as a motor and an electromagnetic valve. The control signal is input to the PLC6via the I/O device7and the field network HUB8.

(HMI Client2)

The HMI client2displays an HMI screen21on a monitor. The HMI client2executes a web browser20as display software, for example, thereby displaying the HMI screen21on the web browser20.

On the HMI screen21, a general-purpose operation part22and a general-purpose operation part23are arranged. The general-purpose operation part22is a part for changing, each time selected, an association state between a field device A (10A) and the hardware switch3. In addition, the general-purpose operation part22is a first software part for displaying information on association setting between the field device A (10A) and the hardware switch3. Similarly, the general-purpose operation part23is a part for changing, each time selected, an association state between a field device B (10B) and the hardware switch3. In addition, the general-purpose operation part23is a first software part for displaying information on association setting between the field device B (10B) and the hardware switch3. The association setting information is information that indicates either an “association state” in which a field device10and the hardware switch3are associated with each other or a “non-association state” in which the field device10and the hardware switch3are not associated with each other.

In addition, on the HMI screen21, a window part24whose display position can be freely changed within the HMI screen21by an operator's operation is arranged. The window part24is a second software part.

When an operator operates a part on the HMI screen21by using an input device such as a mouse or a touch panel, an HMI operation signal is transmitted to the HMI server5. The HMI operation signal includes an item name unique for each part of the HMI screen21, and an operation value. The item name is defined so as to be unique within the HMI system, for example, by combining a screen name of the HMI screen21on which the part is arranged and a number which is sequentially assigned to each part within the HMI screen21.

When an operator operates the general-purpose operation part22or23, an association change signal is transmitted as an HMI operation signal to the HMI server5. The association change signal includes an item name of the general-purpose operation part and an operation value. In addition, the HMI client2receives a feedback signal from the HMI server5as a response to the association change signal. The feedback signal includes the association setting information described above. For example, when the association setting information is information that indicates an association state in which the field device A (10A) and the hardware switch3are associated with each other, the HMI client2causes the general-purpose operation part22related to the field device A (10A) to blink. By causing blinking, the operator can recognize that the field device A (10A) and the hardware switch3are in an association state. The same applies to the general-purpose operation part23.

In addition, the HMI client2transmits, when the window part24overlaps with at least part of the general-purpose operation part22, an association cancellation signal for cancelling the association state in which the field device A (10A) and the hardware switch3are associated with each other, to the HMI server5. Similarly, when the window part24overlaps with at least part of the general-purpose operation part23, it transmits an association cancellation signal for cancelling the association state in which the field device B (10B) and the hardware switch3are associated with each other, to the HMI server5.

(HMI Server5)

The HMI server5stores in advance a conversion table for conversion between an item name of the HMI client2and a PLC address of the PLC6. The HMI server5obtains, when receiving an association change signal from the HMI client2, a PLC address from the conversion table based on an item name of the general-purpose operation part (22or23) included in the association change signal; and transmits an operation value to the PLC6by setting the PLC address as a transmission destination.

In addition, the HMI server5receives a feedback signal from the PLC6as a response to the association change signal. The feedback signal includes the association setting information described above. When the association setting information is information that indicates an association state in which a field device10(10A or10B) and the hardware switch3are associated with each other, the HMI server5starts periodic transmission of a health check signal for the field device10(10A or10B) to the PLC6. The health check signal is a signal whose value periodically changes. As the health check signal, for example, a healthy counter that increments a numerical value for each control cycle, or a heart beat that alternately switches between 0 and 1 for each control cycle is used.

In addition, the HMI server5stops, when receiving an association cancellation signal for a field device10(10A or10B) from the HMI client2, transmission of the health check signal for the field device10to the PLC6.

(PLC6)

The PLC6operates signals from the HMI subsystem30and the hardware switch3by PLC software that is executed by a processor of the PLC6at a fixed cycle.

The PLC6manages information on an association state between the field devices10and the hardware switch3. The PLC6changes, when an operation value is input at a PLC address corresponding to an association change signal, association setting information of a target field device. For example, assume that a target field device is the field device A (10A). When the field device A (10A) and the hardware switch3are in an association state in which they are associated with each other, the PLC6cancels the association state. On the other hand, when the field device A (10A) and the hardware switch3are in a non-association state in which they are not associated with each other, the PLC6associates the field device10A and the hardware switch3with each other.

In addition, when the PLC6receives a health check signal, a memory value of a PLC address corresponding to this signal changes. The PLC6performs operation with reference to the memory value. The PLC6maintains the association state in which the target field device and the hardware switch3are associated with each other, while periodically receiving a health check signal from the HMI subsystem30.

In addition, when the PLC6receives a control signal of the hardware switch3, a memory value of a PLC address corresponding to this signal changes. The PLC6performs operation with reference to the memory value. The PLC6controls, when the target field device and the hardware switch3are in an association state in which they are associated with each other, the drive device9based on the control signal which is output from the hardware switch3. The drive device9controls the target field device based on a signal from the PLC6. On the other hand, when in a non-association state, the PLC6does not control the drive device9.

In addition, the PLC6cancels the association state between the target field device and the hardware switch3when the periodic reception of the health check signal ceases.

(Flowchart)

Hereafter, concrete examples of the following processing will be described with reference to flowcharts inFIG.3toFIG.7.(1) Processing of associating a hardware switch and a field device(2) Processing when the hardware switch is operated(3) Association cancellation processing according to health check(4) Association cancellation processing due to overlapping of parts(5) Association cancellation processing due to poor communication
(1) Processing of Associating a Hardware Switch and a Field Device

FIG.3is a flowchart for describing processing of associating the hardware switch3and a field device10. As one example, a case where the general-purpose operation part23is operated will be described.

First, at step S100, an operator presses down the general-purpose operation part23for associating the field device B (10B) and the hardware switch3. When the general-purpose operation part23is pressed down, an association change signal is transmitted from the HMI client2to the HMI server5. The association change signal includes an item name of the general-purpose operation part23and an operation value.

At step S110, the HMI server5obtains a PLC address corresponding to the item name, from the conversion table; and transmits the operation value to the PLC6by setting the PLC address as a transmission destination.

At step S120, the PLC6checks information on an association state between the field device B (10B) and the hardware switch3; and determines whether they are in an association state or in a non-association state. If in a non-association state at this time, the PLC6associates the field device B (10B) and the hardware switch3(step S130).

On the other hand, if in an association state at this time, the PLC6cancels association between the field device B (10B) and the hardware switch3(step S140). The PLC6stores association state information that is a processing result of step S130or S140.

At step S150, the PLC6transmits a feedback signal including the association state information to the HMI server5. The HMI server5receives the feedback signal.

Next, at step S160, the HMI server5determines whether the information on an association state between the field device B (10B) and the hardware switch3indicates an association state or a non-association state.

In the case of an association state, the HMI server5starts periodic transmission of a health check signal to the PLC6(step S170). For example, a signal value is counted up for each transmission cycle.

On the other hand, in the case of a non-association state, the HMI server5stops transmission of a health check signal (step S180).

At step S190, the HMI server5transmits a feedback signal to the HMI client2. The HMI client2causes, if association state information included in the feedback signal indicates an association state, the general-purpose operation part23, which has been pressed down at step S100, to blink. On the other hand, in the case of a non-association state, it stops the general-purpose operation part23from blinking.

Although processing ofFIG.3has been described above by using the general-purpose operation part23as an example, similar processing is performed also in a case where the general-purpose operation part22for associating the field device A (10A) and the hardware switch3is operated.

(2) Processing when the Hardware Switch is Operated

FIG.4is a flowchart for describing processing when the hardware switch is operated.

First, at step S200, the PLC6receives a control signal from the hardware switch3.

At step S210, the PLC6checks a memory value stored in a PLC address corresponding to the control signal.

At step S220, the PLC6checks association state information and checks whether there is a field device10that is associated with the hardware switch3. If there is no field device10that is associated with the hardware switch3, any field device10is not controlled and a return to step S200is made and processing continues.

On the other hand, if there is a field device10that is associated with the hardware switch3, the PLC6controls the field device via the drive device9based on the control signal (step S230).

(3) Association Cancellation Processing According to Health Check

FIG.5is a flowchart for describing association cancellation processing according to health check.

First, at step S300, the PLC6periodically checks a memory value stored in a PLC address corresponding to a health check signal of each of the field device A (10A) and the field device B (10B).

At step S310, if the memory value for the health check signal is changed within a fixed period of time, the PLC6returns to step S300and continues processing.

On the other hand, if a value of the healthy counter is not changed for a fixed period of time, the PLC6forcibly cancels an association state between a corresponding field device and the hardware switch3(step S320).

(4) Association Cancellation Processing Due to Overlapping of Parts

The programmable logic controller cancels, when the second software part overlaps with at least part of the first software part on the screen, the state in which the field device and the hardware switch are associated with each other.

FIG.6is a flowchart for describing association cancellation processing in a case where a general-purpose operation part is hidden by a window part. As one example, a case where the field device B (10B) and the hardware switch3are in an association state in which they are associated with each other will be described.

First, at step S400, the HMI client2detects the position and size of a part each time the coordinates and size of the part are changed, for example, by a script that runs on the web browser20.

At step S410, the HMI client2determines whether the window part24overlaps with at least part of the general-purpose operation part23. Overlapping of parts will be described with reference toFIG.7. When a part C (25) illustrated in (A) ofFIG.7is pressed down, the window part24is displayed as illustrated in (B). In some cases, the position of the window part24is changed by an operator's operation, so that part of the general-purpose operation part23is overlapped with as illustrated in (C) ofFIG.7. At step S410, whether there is overlapping of parts is determined from the coordinates and size of each part. If there is no overlapping of parts, a return to step S400inFIG.6is made and processing resumes when change in coordinates of any of the parts occurs.

On the other hand, if there is overlapping of parts, the HMI client2outputs to the HMI server5an association cancellation signal for cancelling the association state between the field device B (10B) and the hardware switch3. The HMI server5stops transmission of a health check signal for the field device B (10B) (step S420).

At step S430, the PLC6forcibly cancels the association state between the field device B (10B) and the hardware switch3.

Although processing ofFIG.6has been described above by using, as an example, a case where the field device B (10B) and the hardware switch3are in an association state, similar processing is performed also in a case where the field device A (10A) and the hardware switch3are in an association state.

(5) Association Cancellation Processing Due to Poor Communication

If communication between the HMI server5and the PLC6is interrupted, the PLC6cannot receive a health check signal. As a result, processing similar to that of the workflow inFIG.5, which has been described above, is executed. More specifically, when the periodic reception of a health check signal ceases, the PLC6cancels association between the hardware switch3and all the field devices10. This can prevent an erroneous operation due to a deteriorated communication state between the HMI subsystem30and the PLC6.

As described above, according to the plant monitoring and control system of the present embodiment, it can be detected that the window part24overlaps, on the HMI screen21, with at least part of a general-purpose operation part that displays information on an association state between a field device10and the hardware switch3. In addition, when overlapping of the parts is detected, transmission of a health check signal is stopped and thereby, the association state is cancelled in the same manner as when communication between the HMI server5and the PLC6is interrupted. Thus, in a state in which it is hard for an operator to visually check an association state between the field device10and the hardware switch3, a human error can be prevented.

(Modification)

In the system of the first embodiment described above, the HMI subsystem30is constituted by two computers: a computer for the HMI client2and a computer for the HMI server5. However, the number of computers that constitute the HMI subsystem30is not limited to this and may be three or more. In addition, the HMI subsystem30may be constituted by one computer that includes a function of the HMI client2and a function of the HMI server5.

Furthermore, in the system of the first embodiment described above, a situation in which one hardware switch3is associated with both of the field devices A and B is allowed. In other words, the PLC software is designed so as to allow control of the field device A and the field device B in a linked manner. However, design of the PLC software is not limited to this. The hardware switch3may be associated with only either one of the field device A and the field device B. More specifically, it is acceptable that association with one field device (for example, A) is forcibly cancelled and association with the other field device (for example, B) is performed.

(Hardware Configuration Example)

FIG.8is a block diagram that illustrates a hardware configuration example of each of the HMI client2, the HMI server5, and the PLC6. Each of the devices includes at least a processor71, a memory72, and a network interface73. In addition, the HMI client2includes an input/output interface74and a monitor75.

The memory72includes main memory such as ROM and RAM and auxiliary memory such as an HDD and an SSD. The network interface73is a device that can transmit and receive a signal to and from the outside. The input/output interface74includes an input device such as a keyboard, a mouse, or a touch panel. Each of the devices functions as a processing circuit that implements the above-described processing by the processor71executing each kind of programs stored in the memory72.

Although the embodiment according to the present disclosure has been described above, the present disclosure is not limited to the above embodiment and can be variously modified without departing from the spirit of the present disclosure.

REFERENCE SIGNS LIST

1Monitoring device2HMI client3Hardware switch4Control network HUB5HMI server6Programmable logic controller (PLC)7I/O device8Field network HUB9Drive device10,10A,10B Field device20Web browser21HMI screen22,23General-purpose operation part24Window part30HMI subsystem71Processor72Memory73Network interface74Input/output interface75Monitor