Plc system and backup method therefor

【0001】

[Technical field to which the invention belongs]

The present invention relates to a PLC system in which a plurality of PLCs (program controllers) drive and control a plurality of controlled devices that form a group depending on their own device, and in particular, when an abnormality occurs in the program controller, another program is used. The present invention relates to a PLC system in which a controller drives and controls and backs up a plurality of controlled devices in a group subordinate to the program controller in which an abnormality has occurred.

【0002】

[Conventional technology]

In a conventional PLC system, an execution system PLC and a backup system PLC are provided, and the execution system PLC (program controller) drives and controls multiple subordinate controlled devices, and an error occurs in the execution system PLC. In this case, the duplex PLC is configured to switch from the execution system PLC to the backup system PLC and continuously drive and control multiple controlled devices that are dependent on the execution system PLC in the standby system PLC. The one with the structure is known.

【0003】

Further, as disclosed in Patent Document 1, the conventional programmable controller control system is duplicated with a redundant master station side programmable controller (program controller) in which one is an executing system and the other is a standby system. A programmable controller including a transmission device that transmits information by optical signals provided in each of the master station side programmable controllers and a slave station side connection device that is controlled based on the information transmitted via the transmission device. In the control system, each transmission device of the master station side programmable controller is connected to the input / output end on one side, and the slave station side connection device (controlled device) is parallel to the input / output end on the other side. It is provided with a connected optical switch means and a duplex control means for switching the optical switch means from the master station side programmable controller of the executing system to the master station side programmable controller of the standby system in the event of an abnormality of the master station side programmable controller of the executing system. There is a configuration.

【0004】

With such a configuration, it is possible to instantly switch from the abnormal system of the PLC to the normal system, so that the pause time and malfunction of the controlled object (equipment) can be minimized.

【0005】

[Patent Document 1]

Japanese Unexamined Patent Publication No. 9-73304 (see FIG. 1) [0006]

[Problems to be Solved by the Invention]

In the conventional PLC system (programmable controller control system), the PLC has a dual configuration of an active system and a standby system (or standby system), and if the active system is abnormal, it is switched to the standby system (or standby system). It is possible to continuously drive and control the control target (equipment), but the basic idea of duplicating the PLC is to back up (compensate) when an abnormality occurs in the PLC of the execution system, and the execution system. If the PLC is normal, there is no role of a backup system (or standby system), and there are cases where it is difficult to introduce it into a system where the amount of capital investment is limited.

【0007】

On the other hand, even in systems where reliability is not so required, there is a demand that the controlled device should not be stopped due to a PLC abnormality, and there is a growing demand from users who want to support PLC duplication and multiplexing at a low price. Tend to be.

【0008】

The present invention has been made to solve such a problem, and the purpose of the present invention is to avoid the abnormality easily even if an abnormality occurs in the PLC, and to continuously drive and control the controlled device at a low price. The purpose is to provide a highly reliable PLC system.

【0009】

[Means for solving problems]

In order to solve the above problems, the PLC system according to the present invention is a PLC system including a plurality of program controllers and a plurality of controlled devices that are driven and controlled by forming a group subordinate to each program controller. Each program controller stores the control target device subordinate to its own device and other devices for each group, and drives / controls or stops / controls the control target device for each group, and one program controller has an abnormality. When it occurs, another program controller drives and controls the controlled device of the group subordinate to one program controller in which the abnormality has occurred in a preset order.

【0010】

Each program controller of the PLC system according to the present invention stores the control target device subordinate to its own device and other devices for each group, and drives / controls or stops / controls the control target device for each group. When an error occurs in one of the program controllers, another program controller drives and controls the controlled device of the group subordinate to the one program controller in which the error occurred in a preset order. The program controller that drives and controls the controlled devices of the group subordinate to the program controller can also drive and control the controlled devices of the group subordinate to its own device, achieving low cost and high reliability of multiplexing. can do.

【0011】

Further, the PLC system according to the present invention is characterized by including a communication transmission line connecting each program controller and a control transmission line connecting each program controller and the controlled devices of all groups.

【0012】

Since the PLC system according to the present invention includes a communication transmission line connecting each program controller and a control transmission line connecting each program controller and the controlled devices of all groups, an abnormality occurs via the communication transmission line. It is possible to detect the program controller in which the problem has occurred, and to drive and control the controlled device of the group subordinate to the program controller in which the abnormality has occurred via the control transmission line by subordinating it to another program controller.

【0013】

Further, the control transmission line according to the present invention is characterized in that each program controller is provided with a branch unit for branching a plurality of controlled devices in a group, and is composed of a bus.

【0014】

Since the control transmission line according to the present invention includes a branch unit for branching each program controller and a plurality of control target devices of the group and is composed of a bus, the transmission line to the control target device connected to the branch unit is independent. , It is possible to separate the obstacles of the transmission line and facilitate the wiring with the bus configuration.

【0015】

Further, each program controller according to the present invention is characterized in that the controlled devices of all groups are set by independent addresses, and the drive / control or stop / control of the controlled devices for each group is set by flags. To do.

【0016】

Each program controller according to the present invention sets the controlled devices of all groups with independent addresses, and sets the drive / control or stop / control of the controlled devices for each group with flags, so that the program controller is abnormal. When an error occurs, the controlled device subordinate to the program controller in which the error occurred can be automatically switched to be subordinate to another program controller, and the switched controlled device can be continuously driven and controlled. You can appeal the convenience.

【0017】

Further, the PLC system backup method according to the present invention is a PLC system backup method including a plurality of program controllers and a plurality of controlled devices that are driven and controlled by forming a group subordinate to each program controller. The step (S1) in which another PLC detects the occurrence of an abnormality in one PLC, the step (S2) in which another PLC searches for a controlled device in a group subordinate to the PLC in which the abnormality occurred, and the searched control. Depends on the step (S3) of determining whether or not the target device exists, the step (S4) of driving and controlling the set flag of the control target device if it exists, and the PLC in which the error occurred. It is characterized by having a step (S5) of driving, controlling, and backing up the controlled device of the group to be controlled.

【0018】

The method for backing up a PLC system according to the present invention includes a step (S1) in which another PLC detects an abnormality in one PLC and a step in which another PLC searches for a controlled device in a group subordinate to the PLC in which the abnormality has occurred. (S2), a step (S3) for determining whether or not the searched controlled device exists, and a step (S4) for driving and controlling the set flag of the controlled device if it exists. Since it has a step (S5) to drive, control, and back up the controlled device of the group subordinate to the PLC that caused the abnormality, the PLC that drives and controls the controlled device of its own group has an abnormality. It can be used as a backup for the drive and control of the controlled device of the PLC group, and it is possible to multiplex the backup of the PLC abnormality and greatly improve the reliability.

【0019】

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a basic block configuration diagram of an embodiment of a PLC system according to the present invention. In FIG. 1, the PLC system 1 has PLCs (program controllers) -A to PLC-N as master stations, and is subordinate to PLCs-A to PLC-N to form groups A to N, respectively. It consists of EA3, EB1 ~ EB3, ..., EN1 ~ EN3.

【0020】

PLC-A to PLC-N are all addresses of controlled devices EA1 to EA3, EB1 to EB3, ..., EN1 to EN3, and controlled devices EA1 to EA3, EB1 to EB3, ..., EN1 to EN3, respectively. It is equipped with a storage area that stores all the flags that specify the drive and control of the device and all the control data of the controlled devices EA1 to EA3, EB1 to EB3, ..., EN1 to EN3 for each group A to N.

【0021】

In addition, PLC-A to PLC-N can be controlled devices EA1 to EA3, EB1 to EB3, ..., EN1 to EN3 for each of the subordinate groups A to N under normal operating conditions where there is no abnormality in the PLC. Drive and control independently.

【0022】

Furthermore, PLC-A to PLC-N are controlled devices of the group in which a normal PLC is subordinate to the PLC in which the error occurred in a preset order when an error occurs in any of the PLCs. Is subordinate to itself, and instead of the PLC (master station) where the abnormality has occurred, it becomes the master station (temporary master station) and drives and controls the device to be controlled.

【0023】

For example, when PLC-A to PLC-N are all normal, PLC-A independently drives and controls the controlled target devices EA1 to EA3 which form the group A subordinately. In addition, PLC-B independently drives and controls the controlled target devices EB1 to EB3 that subordinately form group B. Similarly, the PLC-N independently drives and controls the controlled devices EN1 to EN3 that form the group N subordinately.

【0024】

On the other hand, when an abnormality occurs in PLC-B, the controlled device EB1 forms a group B subordinate to PLC-B in place of PLC-B in which PLC-A has an abnormality, for example, in a preset order. ~ EB3 is driven and controlled by being subordinate to the own device together with the controlled devices EA1 to EA3 of group A which are subordinate to the own device.

【0025】

Therefore, PLC-A normally independently drives and controls the controlled devices EA1 to EA3 forming Group A, and when an abnormality occurs in PLC-B, Group B subordinates to PLC-B. Since the controlled devices EB1 to EB3 can be driven and controlled in a subordinate manner to the own device, PLC-A has a redundant structure (backup) from the viewpoint of PLC-B. However, the normal duplex structure is not specially provided by PLC-A for the purpose of backing up PLC-B, and PLC-A, like PLC-B, is a controlled device EA1 that depends on its own device. The difference is that it drives and controls ~ EA3. Also, of course, PLC-B can play a role of backup of PLC-A.

【0026】

Also, if an error occurs in PLC-A from the state in which PLC-A is backing up the PLC-B in which the error occurred, and if the next backup order is preset in PLC-N, PLC-N Subordinates the controlled devices EA1 to EA3 and the controlled devices EB1 to EB3 that formed groups A and B depending on PLC-A to their own device, and forms group N depending on their own device. Drive and control together with the controlled devices EN1 to EN3. The control target devices subordinate to each PLC-A to PLC-N are EA1 to EA3, EB1 to EB3, ..., EN1 to EN3, each of which is three, but four or more may be used.

【0027】

Each PLC-A to PLC-N is connected by a communication transmission channel acquisition LT, and information indicating the operating state is exchanged. For example, when an abnormality occurs in each PLC-A to PLC-N, the abnormality is notified to other PLCs-A to PLC-N via the communication transmission path acquisition LT. Alternatively, when an abnormality occurs in each PLC-A to PLC-N, another PLC-A to PLC-N detects the abnormality via the communication transmission channel acquisition LT.

【0028】

The communication transmission line LT is a transmission in which each PLC can monitor and manage the operating status between PLC-A to PLC-N and the fluctuation of the devices inside PLC-A to PLC-N with data. Represents a road. For example, data from PLC-A to PLC-N to controlled devices EA1 to EA3, EB1 to EB3, ..., EN1 to EN3 (for example, ON / OFF data, analog data, etc.) and PLC-A to PLC- The operating status of N (for example, normal / abnormal), programming calculation result data, etc. are transmitted via the communication transmission line LT and shared between PLCs.

【0029】

That is, communication for sharing memory data is periodically executed between PLC-A to PLC-N via the communication transmission line LT (data link method). Since common memory data is retained between PLC-A to PLC-N, even if an error occurs in any PLC-A to PLC-N, an error occurs in other PLCs-A to PLC-N. By inheriting the data held by the PLC that has just occurred, it is possible to continuously drive and control the controlled devices of the group that the PLC that has the error drives and controls.

【0030】

In addition, between each PLC-A to PLC-N and between each PLC-A to PLC-N and the controlled devices EA1 to EA3, EB1 to EB3, ..., EN1 to EN3 of the subordinate groups A to N , Connected by control transmission line LC via branch units D1 to Dn, and drives and controls controlled devices EA1 to EA3, EB1 to EB3, ..., EN1 to EN3 from PLC-A to PLC-N. The control transmission line LC is composed of buses and transmits serial control signals SCA, SCB, ..., SCN.

【0031】

The branch units D1 to Dn connect Group A to Group N, and PLC-A and the control target device EA1 to EA3, PLC-B and the control target device EB1 to EB3, ..., PLC-N. Branch and connect each of the controlled devices EN1 to EN3.

【0032】

Since groups A to N are connected by a control transmission line LC via branch units D1 to Dn, if an error occurs in PLC-A to PLC-N, the PLC in which the error occurred via the control transmission line LC -Controlled devices EA1 to EA3, EB1 to EB3, ..., EN1 to EN3 of groups A to N subordinate to A to PLC-N can be subordinate to other PLCs-A to PLC-N.

【0033】

In addition, since the control target devices EA1 to EA3, EB1 to EB3, ..., EN1 to EN3 are independently connected by the control transmission line LC via the branch units D1 to Dn, the control target devices EA1 to EA3, EB1 to EB3 , ..., Even if a failure occurs in the control transmission line LC connecting EN1 to EN3, the failure of the control transmission line LC is separated and the failure is minimized.

【0034】

The control transmission line LC can also be used as the communication transmission line LT. The first method is to provide a communication transmission line master in one PLC-A to PLC-N (for example, PLC-A) and to provide a communication transmission line in another PLC (for example, PLC-B to PLC-N). Provide a slave for. Master-slave type data link communication is performed between the communication transmission line master and the communication transmission line slave via the control transmission line LC, and the operating status between PLC-A to PLC-N and PLC-A to PLC -N Data such as internal device fluctuations can be shared.

【0035】

The second method is to provide a communication transmission line master in one PLC-A to PLC-N (for example, PLC-A) and control transmission lines for other PLCs (for example, PLC-B to PLC-N). This method uses the slave function built into the master (for example, the function of communicating CPU data to the master as a slave and the data of the master CPU to the slave CPU). PLCs with slave functions (for example, PLC-B to PLC-N) each play the role of master for the controlled devices of their own group, and also play the role of slave for the master for communication transmission lines. It works. The master for communication transmission line (for example, PLC-A) is the data of the slave function inside other PLCs (for example, PLC-B to PLC-N), the operating status between PLC-A to PLC-N, and PLC-. Collects and stores data such as device fluctuations inside A to PLC-N. Then, data is provided from the communication transmission line master (for example, PLC-A) to the slave functions inside other PLCs (for example, PLC-B to PLC-N) via the control transmission line LC. Can be shared.

【0036】

The PLC system 1 according to the present invention includes a communication transmission path acquisition LT that connects each program controller (PLC-A to PLC-N), each program controller (PLC-A to PLC-N), and all groups (A to). Since it is equipped with a control transmission line LC that connects the controlled devices (EA1 to EA3, EB1 to EB3, ..., EN1 to EN3) of N), the program controller in which an error occurred via the communication transmission line LT Can be driven and controlled by subordinating the controlled device of the group subordinate to the program controller in which the abnormality has occurred to another program controller via the control transmission line LC.

【0037】

Further, the control transmission line LC according to the present invention includes a plurality of controlled devices (EA1 to EA3, EB1 to EB3, ...,) of each program controller (PLC-A to PLC-N) and a group (A to N). Since the branch units D1 to Dn that branch EN1 to EN3) are provided and configured with a bus, the controlled devices (EA1 to EA3, EB1 to EB3, ..., EN1 to EN3) connected to the branch units D1 to Dn. The transmission lines up to can be made independent, the obstacles of the transmission line LC can be separated, and the wiring can be facilitated by the bus configuration.

【0038】

As described above, the program controllers (PLC-A to PLC-N) of the PLC system 1 according to the present invention are controlled target devices (EA1 to EA3,) for each group (A to N) subordinate to the own device and other devices. EB1 ~ EB3, ..., EN1 ~ EN3) are memorized, and the controlled devices (EA1 ~ EA3, EB1 ~ EB3, ..., EN1 ~ EN3) are driven / controlled for each group (A ~ N). When stop / control is executed and an error occurs in any program controller (PLC-A to PLC-N), an error occurs in other program controllers (PLC-A to PLC-N) in a preset order. Since the controlled device of the group subordinate to the program controller is driven and controlled, the program controller that drives and controls the controlled device of the group subordinate to the program controller in which the abnormality has occurred is the control target of the group subordinate to the own device. Equipment can also be driven and controlled, and high reliability of multiplexing can be realized at a low price.

【0039】

FIG. 2 is an image diagram of an embodiment storage area of a program controller according to the present invention. In FIG. 2, PLC-A to PLC-N store storage areas having addresses, flags, and control data of all controlled devices EA1 to EA3, EB1 to EB3, ..., EN1 to EN3 of groups A to N, respectively. Be prepared.

【0040】

The storage area of PLC-A, the storage area of PLC-B, ..., and the storage area of PLC-N are the controlled devices EA1 to EA3 and EB1 to EB3 of group A, group B, ..., and group N, respectively. , ..., EN1 to EN3 independent addresses, controlled devices EA1 to EA3, EB1 to EB3, ..., EN1 to EN3 are driven / controlled or stopped / controlled (for example, drive / control is "1", stop / control is "0"), and the control data that drives / controls the controlled devices EA1 to EA3, EB1 to EB3, ..., EN1 to EN3 are stored in common.

【0041】

PLC-A, PLC-B, ..., PLC-N program execute the storage areas of groups A to N, respectively, but output control data with a flag of "1" and a flag of "0"). The output of the control data of is prohibited.

【0042】

Alternatively, PLC-A, PLC-B, ..., PLC-N may be configured to output control data with a flag of "1" and skip the portion with a flag of "0".

【0043】

When PLC-A to PLC-N shown in FIG. 1 are normal, PLC-A uses the control data Da1 to Da3 of only the part (group A) where the flag of the PLC-A storage area is "1" as the control signal SCA. It outputs and drives and controls the controlled devices EA1 to EA3.

【0044】

The PLC-B outputs control data Db1 to Db3 of only the part (group B) in which the flag of the PLC-B storage area is "1" as a control signal SCB, and drives and controls the control target devices EB1 to EB3. Similarly, PLC-N outputs control data Dn1 to Dn3 of only the part (group N) where the flag of the PLC-N storage area is "1" as a control signal SCN, and drives the controlled devices EN1 to EN3. Control.

【0045】

Next, backup when an abnormality occurs in the PLC (program controller) will be described. FIG. 3 is an explanatory diagram of an embodiment of PLC abnormality backup according to the present invention. In Fig. 3, when an abnormality occurs in PLC-B (abnormality occurrence 1 ), PLC-B stops the output of the control signal SCB and transmits the abnormality information JX via the communication channel acquisition LT to PLC-A. , Transmit to PLC-C to PLC-N. Here, if the order is set in advance so that PLC-A backs up PLC-B, PLC-A changes the flag of group B in the PLC-A storage area from "0" to "1". Then, the control signal SCA and the control signal SCB are output.

【0046】

The control signal SCB is transmitted to the branch unit D2 via the branch unit D1 to drive and control the control target devices EB1 to EB3 of the group B. In other words, it is possible to realize backup (duplication) of PLC-B in which an abnormality has occurred due to PLC-A.

【0047】

FIG. 4 is an explanatory diagram of another embodiment of the PLC abnormality backup according to the present invention. Note that Fig. 4 shows the state in which PLC-N backs up when an error occurs in PLC-A that backed up PLC-B. In Fig. 4, when an abnormality occurs in PLC-A (abnormality occurrence 2 ), PLC-A stops the output of the control signals SCA and SCB, and transmits the abnormality information JX to the PLC via the communication channel acquisition LT. -Transmit to C ~ PLC-N. Here, if the order is set in advance so that the PLC-N backs up the PLC-A, the PLC-N sets the flags of the group A and the group B of the PLC-N storage area from "0" to "1". Is changed to, and the control signal SCA, control signal SCB, and control signal SCN are output.

【0048】

The control signal SCB is transmitted to the branch unit D2 via the branch unit Dn, and drives and controls the control target devices EB1 to EB3 of the group B. On the other hand, the control signal SCA is transmitted to the branch unit D1 via the branch unit Dn to drive and control the control target devices EA1 to EA3 of the group A.

【0049】

That is, it is possible to back up PLC-B and PLC-A in which an abnormality has occurred by PLC-N, to realize duplication for PLC-A, and to realize triplet for PLC-B.

【0050】

Since each of PLC-A to PLC-N can back up N PLCs, this PLC system 1 should construct N-multiplexing (multiplexing) of PLCs without providing a special PLC dedicated to backup. Can be done.

【0051】

As described above, each program controller (PLC-A to PLC-N) according to the present invention has independent control target devices EA1 to EA3, EB1 to EB3, ..., EN1 to EN3 of all groups A to N. In addition to setting by address, drive / control or stop / control of the controlled device for each group A to N is set by a flag, so if an error occurs in the program controller, the control target that depends on the program controller in which the error occurred Switching to make a device subordinate to another program controller is automatically executed, and the switched controlled device can be continuously driven and controlled, which can appeal the convenience.

【0052】

In addition, by applying the present invention, even if an abnormality does not occur in PLC-A to PLC-N, it is desired to carry out maintenance and inspection of PLC-A to PLC-N without periodically stopping the operation. In addition, by substituting another PLC for the PLC to be maintained / inspected, it is possible to carry out the maintenance / inspection of all PLCs in the system.

【0053】

Next, a method of packing up the PLC system will be described. FIG. 5 is an operation flow diagram of a main part of an embodiment of a PLC system pack-up method according to the present invention.

【0054】

In FIG. 5, in step S1, another PLC detects the occurrence of an abnormality in one PLC.

【0055】

In step S2, the controlled device of the group subordinate to the PLC in which the other PLC has an abnormality is searched.

【0056】

In step S3, it is determined whether or not the searched controlled device exists, and if it exists, the process proceeds to step S4. On the other hand, if it does not exist, the process ends.

【0057】

In step S4, the set flag of the controlled device is driven / controlled.

【0058】

In step S5, the controlled devices of the group subordinate to the PLC in which the abnormality has occurred are driven, controlled, and backed up.

【0059】

As described above, in the method of backing up the PLC system according to the present invention, step S1 in which another PLC detects the occurrence of an abnormality in one PLC and the controlled device of the group subordinate to the PLC in which the other PLC has an abnormality are searched. Step S2 to perform, step S3 to determine whether or not the searched controlled device exists, and if so, step S4 to drive and control the set flag of the controlled device, and an abnormality occurs. Since it is equipped with step S5 to drive, control, and back up the controlled device of the group subordinate to the PLC, the PLC that drives and controls the controlled device of the own group can be controlled by the group of PLCs that have an abnormality. It can be used as a backup for the drive and control of the target device, and it is possible to multiplex the backup of PLC abnormalities and greatly improve reliability.

【0060】

[Effect of the invention]

As described above, each program controller of the PLC system according to the present invention stores the control target device subordinate to its own device and other devices for each group, and drives / controls or stops the control target device for each group. When control is executed and an error occurs in one program controller, the other program controllers drive and control the controlled devices of the group subordinate to the one program controller in which the error occurred in a preset order. The program controller that drives and controls the controlled device of the group subordinate to one program controller in which the abnormality has occurred can also drive and control the controlled device of the group subordinate to its own device, and is multiplexed at a low cost. High reliability can be realized.

【0061】

Further, in the method of backing up the PLC system according to the present invention, the step (S1) in which another PLC detects the occurrence of an abnormality in one PLC and the controlled device of the group subordinate to the PLC in which the other PLC has an abnormality are searched. Step (S2), a step (S3) to determine whether or not the searched controlled device exists, and a step (S4) to drive and control the set flag of the controlled device if it exists. ) And the step (S5) to drive, control, and back up the controlled device of the group subordinate to the PLC that caused the error, so the PLC that drives and controls the controlled device of the own group is abnormal. It can be used as a backup for the drive and control of the controlled device of the PLC group in which the PLC has occurred, and the backup of the PLC abnormality can be multiplexed to greatly improve the reliability.

[Simple explanation of drawings]

FIG. 1 is a basic block configuration diagram of an embodiment of a PLC system according to the present invention. FIG. 2 is an image diagram of a storage area of an embodiment of a program controller according to the present invention. FIG. 3 is an implementation of PLC abnormality backup according to the present invention. [Fig. 4] An explanatory diagram of another embodiment of PLC abnormality backup according to the present invention [Fig. 5] An operation flow diagram of a main part of an embodiment of a PLC system pack-up method according to the present invention. ]

1 PLC system A ~ N PLCD1 ~ Dn Branch unit EA1 ~ EA3, EB1 ~ EB3, ..., EN1 ~ EN3 Control target device LT Communication transmission line Obtain LC Control transmission line ADa1 ~ ADa3, ADb1 ~ ADb3, ..., ADn1 ~ ADn3 Address Da1 ~ Da3, Db1 ~ Db3, ..., Dn1 ~ Dn3 Control data