Control device, control system, support device, and control-device maintenance management method

Abstract

A support device executes a maintenance operation for a PLC, and records, into the PLC, information identifying the maintenance operation. The maintenance operation includes at least either of writing and deleting of data such as firmware into/from the PLC. The support device may further record, into the support device itself, information identifying the maintenance operation. In addition, the PLC uses data stored in a recording medium to execute a maintenance operation for the PLC. At this time, the PLC records, into the PLC itself, information identifying the maintenance operation. The PLC may further record, into the recording medium, the information identifying the maintenance operation.

Claims

1. A control device for controlling a production system, the production system including at least one of a relay and a servo motor driver driving a motor, the control device comprising: a storage device; a communication interface, the communication interface enabling communication between the control device and a support device; and a processor to perform operations comprising: receiving, via the communication interface, a communication request from the support device, receiving, via the communication interface, firmware maintenance information from the support device, writing, into the storage device, the firmware maintenance information, sending, via the communication interface, a result of writing the firmware maintenance information, determining that an instruction to write a description associated with the firmware maintenance information, a date and time of when the firmware maintenance information was written, and an identification of the support device has been received from the support device, writing, into the storage device and in response to the determining, the description, the date and time, and the identification, and controlling the at least one of the relay and the servo motor driver based on the firmware maintenance information.

2. The control device according to claim 1, wherein the description includes information identifying a name of the firmware maintenance information written in the storage device.

3. The control device according to claim 1, wherein the description includes information identifying that the firmware maintenance information is deleted.

4. A control system. comprising: a control device; and a support device, wherein: the control device comprises a first storage device and a first processor to perform operations for controlling a production system, the production system including at least one of a servo motor driver driving a motor; the support device comprises a second storage device and a second processor to perform operations to communicate with the first processor of the control device; the control device further comprises a first communication interface, the first communication interface enabling communication between the control device and the support device; the support device further comprises a second communication interface, the second communication interface enabling communication between the support device and the control device; the second processor to perform operations further comprising: sending, via the second communication interface, a communication request to the first processor, sending, via the second communication interface, firmware maintenance information to the first processor, receiving, via the second communication interface, a result of the first processor writing the firmware maintenance information to the first storage device, determining that the firmware maintenance information was successfully written based on the received result, writing, into the second storage device, a description associated with the firmware maintenance information a, date and time of when the firmware maintenance information was written, and an identification of the control device, and sending, via the second communication interface, an instruction to write the description, the date and time, and an identification of the support device to the first storage device; and the first processor to perform operations further comprising: receiving, via the first communication interface, the communication request from the second processor, receiving, via the first communication interface, the firmware maintenance information from the second processor, writing, into the first storage device, the firmware maintenance information, sending, via the first communication interface, the result of writing the firmware maintenance information, determining that the instruction from the second processor has been received, writing, into the first storage device and in response to the determining, the description, the date and time, and the identification of the support device, and controlling the at least one of the relay and the servo motor driver based on the firmware maintenance information.

5. The control system according to claim 4, wherein the support device further comprises a display, and wherein the display displays a history of the firmware maintenance information.

6. A support device comprising: a processor; a communication interface, the communication interface enabling communication between the support device and a control device, the control device controlling a production system including at least one of a relay and a servo motor driver driving a motor; and a storage device, the processor to perform operations comprising: sending, via the communication interface, a communication request to the control device, sending, via the communication interface, firmware maintenance information to the control device, receiving, via the communication interface, a result of the control device writing the firmware maintenance information to the control device, determining that the firmware maintenance information was successfully written based on the received result, writing, into the storage device, a description associated with the firmware maintenance information, a date and time of when the firmware maintenance information was written, and an identification of the control device, and sending, via the communication interface, an instruction to write the description, the date and time, and an identification of the support device to the control device, wherein the control device controls the at least one of the relay and the servo motor driver based on the firmware maintenance information.

7. The support device according to claim 6, wherein the support device further comprises a display, and wherein the display displays a history of the firmware maintenance information.

8. A control device maintenance management method to be executed by a processor of a control device for controlling a production system, the production system including at least one of a relay and a servo motor driver driving a motor, the control device comprising storage device and a communication interface, the communication interface enabling communication between the control device and a support device, the control-device maintenance management method comprising: receiving, via the communication interface, a communication request from the support device, receiving, via the communication interface, firmware maintenance information from the support device, writing, into the storage device, the firmware maintenance information, sending, via the communication interface, a result of writing the firmware maintenance information, determining that an instruction to write a description associated with the firmware maintenance information, a date and time of when the firmware maintenance information was written, and an identification of the support device has been received from the support device, writing, into the storage device and in response to the determining, the description, the date and time, and the identification, and controlling the at least one of the relay and the servo motor driver based on the firmware maintenance information.

9. A support device maintenance management method to be executed by a processor of a support device configured to communicate with a control device for controlling a production system including at least one of a rely and a servo motor driver driving a motor, the support device comprising a storage device and a communication interface, the communication interface enabling communication between the support device and the control device, the support device maintenance management method comprising: sending, via the communication interface, a communication request to the control device, sending, via the communication interface, firmware maintenance information to the control device, receiving, via the communication interface, a result of the control device writing the firmware maintenance information to the control device, determining that the firmware maintenance information was successfully written based on the received result, writing, into the storage device, a description associated with the firmware maintenance information, a date and time of when the firmware maintenance information was written, and an identification of the control device, and sending, via the communication interface, an instruction to write the description, the date and time, and an identification of the support device to the control device, wherein the control device controls the at least one of the relay and the servo motor driver based on the firmware maintenance information.

10. The support device maintenance management method according to claim 9, wherein the support device further comprises a display, and wherein the display displays a history of the firmware maintenance information.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a view schematically illustrating an example configuration of a control system according to an embodiment of the present invention.

(2) FIG. 2 is a view schematically illustrating an example hardware configuration of a support device.

(3) FIG. 3 is a view illustrating an example hardware configuration of a PLC.

(4) FIG. 4 is a view for schematically describing an example maintenance operation for the PLC in the control system according to the embodiment.

(5) FIG. 5 is a schematic view illustrating an example maintenance operation history stored in a nonvolatile memory of the PLC.

(6) FIG. 6 is a schematic view illustrating an example maintenance operation history stored in a maintenance history storing unit of the support device.

(7) FIG. 7 is a schematic view illustrating an example maintenance operation history recorded in a recording medium.

(8) FIG. 8 is a flow chart of an example maintenance operation process executed, for the PLC, by the support device.

(9) FIG. 9 is a flow chart of another example maintenance operation process executed, for the PLC, by the support device.

(10) FIG. 10 is a flow chart of an example maintenance operation process executed by the PLC using the recording medium.

(11) FIG. 11 is a view illustrating an example display in which a maintenance operation history in the support device and a maintenance operation history in the PLC are combined.

(12) FIG. 12 is a view illustrating an example display of a maintenance operation history when a recording medium with an ID 2B63-3AA4 is attached.

(13) FIG. 13 is a view illustrating an example display of a maintenance operation history when a recording medium with an ID 3C87-2EB5 is attached.

MODE FOR CARRYING OUT THE INVENTION

(14) An embodiment of the present invention will now be described in detail with reference to the drawings. At this point, identical numerals and symbols apply to identical or equivalent components shown in the drawings so as not to repeat description of the components.

(15) <Configuration of Control System>

(16) FIG. 1 is a view schematically illustrating an example configuration of a control system according to an embodiment of the present invention. As shown in FIG. 1, the control system includes a PLC 100 and a support device 300. The PLC 100 is an example control device for controlling an FA system. The PLC 100 controls, in the FA system, for example, operations of a relay and a servo motor driver driving a motor. The support device 300 is an example information processing device capable of communicating with the PLC 100. The support device 300 is, for example, a general-purpose computer. The support device 300 sets various parameters, and performs programming, monitoring, debugging, and other tasks for programs to be executed in the PLC 100.

(17) In the control system shown in FIG. 1, the support device 300 executes a maintenance operation for the PLC 100. With the embodiment, writing and deleting firmware into/from a nonvolatile memory 126 of the PLC 100, among various operations included in maintenance operations, will now mainly be described. As described later, the PLC 100 includes an arithmetic operation device (processor 122 shown in FIG. 3) to control an FA system by allowing the arithmetic operation device to execute a program. The maintenance operations for the PLC 100 include, for example, writing, into the PLC 100, data for use in controlling the FA system. In an example maintenance operation, as indicated by an arrow R1 in FIG. 1, the support device 300 writes data into the PLC 100.

(18) In the control system shown in FIG. 1, as indicated by an arrow R3 in FIG. 1, the PLC 100 can also write, into the PLC 100 itself, data recorded in a recording medium 500 to execute a maintenance operation for the PLC 100. The data recorded in the recording medium 500 may be, as indicated by an arrow R2 in FIG. 1, written into the recording medium 500 itself by the support device 300 or another device.

(19) In the control system shown in FIG. 1, the PLC 100 can also execute, under an instruction given by the support device 300, a maintenance operation for the PLC 100 itself. More specifically, for example, the support device 300 instructs, to the PLC 100, writing the data recorded in the support device 300.

(20) In response to this, the PLC 100 writes the data recorded in the support device 300.

(21) Upon the maintenance operation is executed, information identifying the maintenance operation is recorded in the PLC 100. As an example, the information identifying the maintenance operation is written by the support device 300. At this time, the support device 300 may record, into the support device 300 itself, the information identifying the maintenance operation.

(22) As another example, the information identifying the maintenance operation is written by the PLC 100 itself. More specifically, when the PLC 100 writes, into the PLC 100 itself, data recorded in the recording medium 500 to execute a maintenance operation, the PLC 100 further writes, into the PLC 100 itself, information identifying the maintenance operation. At this time, the PLC 100 may record, into the recording medium 500, the information identifying the maintenance operation.

(23) <Hardware Configuration of Support Device 300>

(24) FIG. 2 is a view schematically illustrating an example hardware configuration of the support device 300. As shown in FIG. 2, the support device 300 includes a Central Processing Unit (CPU) 302, a Read Only Memory (ROM) 304, a Random Access Memory (RAM) 306, and a hard disk drive (HDD) 308. The CPU 302 executes various programs including an Operating System (OS). The ROM 304 stores a Basic Input/Output System (BIOS) and a variety of data. The RAM 306 provides a work area for storing data required to execute a program with the CPU 302. The HDD 308 stores in a nonvolatile manner a program and other data to be executed with the CPU 302. The CPU 302 and the RAM 306 configure an example controller in the control system.

(25) The hard disk 308 can store data (program data and/or batch file data) to be sent to the PLC 100 and a history of maintenance operations executed for the PLC 100. In FIG. 2, a program storing unit 330 provides an area for storing an application program for executing a maintenance operation. A data storing unit 331 provides an area for storing data to be sent to the PLC 100. A maintenance history storing unit 332 provides an area for storing a maintenance operation history. A program and data stored in the hard disk 308 can be recorded in a recording medium detachable to and from the support device 300 for distribution separately from the support device 300 itself.

(26) The support device 300 further includes a keyboard 310 and a mouse 312 for accepting operations by a user, a monitor 314 for presenting information to the user, and a Secure Digital (SD) memory card interface 316. The embodiment applies an SD memory card as an example of the recording medium 500. The CPU 302 reads data recorded in the recording medium 500, and records data into the recording medium 500, via the SD memory card interface 316. The support device 300 further includes a communication interface (IF) 318 for communicating with the PLC 100 and other devices.

(27) <Hardware Configuration of PLC 100>

(28) FIG. 3 is a view illustrating an example hardware configuration of the PLC 100. As shown in FIG. 3, the PLC 100 includes a processor 122, a main memory 124, a nonvolatile memory 126, a Light Emitting Diode (LED) 128, an input device 132, a connector 134, and an SD memory card interface 136.

(29) The processor 122 controls an operation of the PLC 100 by executing a program stored in the nonvolatile memory 126 or other storage devices. The main memory 124 can be used as a work area for the processor 122. The nonvolatile memory 126 stores a variety of data such as programs. The LED 128 is an example reporting unit, and is controlled by the processor 122 for a lighting operation. The input device 132 accepts an external input of information, and is configured with, for example, a button. The connector 134 is provided to connect with an external device including a recording medium such as Universal Serial Bus (USB) memory. The processor 122 can communicate with, via the connector 134, the external device. The SD memory card interface 136 is used to read data recorded in an SD memory card, an example of the recording medium 500. The processor 122 reads, via the SD memory card interface 136, the data recorded in the recording medium 500.

(30) <Outline of Maintenance Operation>

(31) FIG. 4 is a view for schematically describing an example maintenance operation for the PLC 100 in the control system according to the embodiment. A left side in FIG. 4 shows the PLC 100 to which no maintenance operation is executed. A right side in FIG. 4 shows the PLC 100 to which a maintenance operation is executed.

(32) The PLC 100 shown on the left side in FIG. 4 is installed with system firmware 150 and an additional function A (program for achieving the function) 170. The system firmware is software providing a basic functionality of the PLC 100. The system firmware includes, for example, software for achieving the basic functionality (program execution, communication, sensing, and other functions) of the PLC 100, an Operating System (OS), or software for controlling a hardware resource (for example, display or memory) mounted on the PLC 100.

(33) The additional function is particular to a production apparatus in which the PLC 100 is mounted. Example functions include temperature control function and special communication function. In addition, different from the basic functionality of the PLC 100, the additional function is added by a manufacturer of the PLC 100 for higher competitiveness to achieve an expected, higher value for the PLC 100. That is, the application functionality may differ depending on a PLC 100, and, in addition, depending on a production apparatus onto which a control device is mounted. The application functionality (additional function) is also called as add-on firmware, and is achieved by a type of firmware for the PLC 100.

(34) The system firmware 150 and the additional function A170 are stored in, for example, the nonvolatile memory 126. In addition, the PLC 100 includes a control memory 160 for storing information for identifying a maintenance operation for the PLC 100. The control memory 160 includes, for example, the nonvolatile memory 126. In the PLC 100, the processor 122 executes the additional function A170 to achieve a particular function.

(35) As an example maintenance operation for the PLC 100, the support device 300 writes, into the nonvolatile memory 126 of the PLC 100, an additional function B (application program for achieving the function). Accordingly, a state of the PLC 100 shifts to another state shown on the right side in FIG. 4. As shown to the right side in FIG. 4, the PLC 100 further includes an additional function B171.

(36) At this point, the PLC 100 can execute a maintenance operation for the PLC 100 itself. More specifically, the processor 122 of the PLC 100 can write, into the nonvolatile memory 126, an application program used for the additional function B and recorded in the recording medium 500. In addition, under an instruction given by the support device 300, the processor 122 writes, into the nonvolatile memory 126, data recorded in the data storing unit 331 of the support device 300.

(37) <Maintenance Operation History Information (PLC 100)>

(38) In the control system according to the embodiment, the PLC 100 stores a history of maintenance operations (maintenance operation history) for the PLC 100. FIG. 5 is a schematic view illustrating an example maintenance operation history stored in the nonvolatile memory 126 of the PLC 100.

(39) As shown in FIG. 5, the maintenance operation history includes dates and time when maintenance operations are executed, information identifying a device that has provided data on each of the maintenance operations (Device in FIG. 5), and contents of the maintenance operations. Each of the contents is, for example, a name of a downloaded program. In addition, the history is assigned with a number identifying each of the maintenance operations.

(40) For example, a maintenance operation shown at 1 in FIG. 5 is a version up of a firmware (FW) program (a type of system firmware) to V2.01 started (or completed) at 09:10:15 on Jan. 5, 2014, and means that data is provided by a computer (PC) identified by an ID AAA. An ID of a PC is an example of information identifying the support device 300. In the embodiment, a computer with an ID AAA means the support device 300. That is, the maintenance operation shown at 1 means that the maintenance operation has been executed by the support device 300. A process content of version up is identified, when the maintenance operation starts, in accordance with a content of data recorded in the nonvolatile memory 126. More specifically, the CPU 302 determines that, when a maintenance operation starts, and a program having a file name identical to a file name of another program to be written through the maintenance operation and a version older than a version of the other program is written in the nonvolatile memory 126 of the PLC 100, a content of the maintenance operation is a version up.

(41) A maintenance operation shown at 3 in FIG. 5 means a deletion of a database (DB) connection function (program for the function) with a version V1.00 started (or completed) at 10:01:01 on Jan. 9, 2014. A Device value of the maintenance operation shown at 3 is PC: BBB. This means that a computer identified by an ID BBB has executed the above described deletion. Deleting a program can include not only deleting data of the program from the nonvolatile memory 126, but also making the data of the program unreadable by the processor 122 by rewriting a directory or taking another action.

(42) On the other hand, the CPU 302 determines that, when a maintenance operation starts, and a program having a file name identical to a file name of another program to be written through the maintenance operation is not written in the nonvolatile memory 126 of the PLC 100, a content of the maintenance operation is addition.

(43) <Maintenance Operation History Information (Support Device 300)>

(44) In the control system according to the embodiment, the support device 300 stores, as a maintenance operation history, information identifying a maintenance operation. FIG. 6 is a schematic view illustrating an example maintenance operation history stored in the maintenance history storing unit 332 of the support device 300.

(45) As shown in FIG. 6, the maintenance operation history includes dates and time when maintenance operations are executed, information identifying a PLC subject to each of the maintenance operations (PLC in FIG. 6), and contents of the maintenance operations. In addition, the history is assigned with a number identifying each of the maintenance operations.

(46) For example, a maintenance operation shown at 3 in FIG. 6 is an addition of a database (DB) connection function (program for the function) with a version V1.00 to a PLC identified by a serial number 45678 started (or completed) at 11:42:53 on Jan. 7, 2014. The serial number is a specific example of an ID of the PLC 100.

(47) <Maintenance Operation History Information (Recording Medium 500)>

(48) In the control system according to the embodiment, the PLC 100 writes, into the nonvolatile memory 126, data recorded in the recording medium 500 to execute a maintenance operation, and then writes, into the recording medium 500, information identifying the maintenance operation. FIG. 7 is a schematic view illustrating an example maintenance operation history recorded in the recording medium 500.

(49) As shown in FIG. 7, the maintenance operation history includes dates and time when maintenance operations are executed, information identifying a PLC subject to each of the maintenance operations (PLC in FIG. 7), and contents of the maintenance operations. In addition, the history is assigned with a number identifying each of the maintenance operations.

(50) For example, a maintenance operation shown at 1 in FIG. 7 is an addition of a robot function (program for the function) with a version V1.01 to a PLC identified by a serial number 56789 started (or completed) at 14:51:16 on Jan. 8, 2014.

(51) <Maintenance Operation Executed by Support Device 300 (1)>

(52) FIG. 8 is a flow chart of an example maintenance operation process executed, for the PLC 100, by the support device 300.

(53) With reference to FIG. 8, in a step SA10, the CPU 302 establishes a communication with the PLC 100. More specifically, for example, an operator inputs, into the support device 300, an instruction on a maintenance operation for the PLC 100. In response to this, the CPU 302 requests the PLC 100 to establish a communication. The processor 122 of the PLC 100 responds the request and establishes the communication between the support device 300 and the PLC 100. Next, a control is allowed to proceed to a step SA12.

(54) In the step SA12, the CPU 302 writes, into the nonvolatile memory 126 of the PLC 100, specified data to be written into the PLC 100. Next, the control is allowed to proceed to a step SA14.

(55) The above described operator, for example, inputs, into the support device 300, information specifying the data to be written. More specifically, the program storing unit 330 of the HDD 308 stores information associating a function with a program for achieving the function. Next, the operator specifies the function. Accordingly, the CPU 302 identifies, as the data to be written into the PLC 100, the program associated with the specified function.

(56) In the step SA14, the CPU 302 determines if writing the data into the nonvolatile memory 126 normally ends. Next, upon the CPU 302 determines that the writing normally ends, the CPU 302 allows the control to proceed to a step SA18 (YES in the step SA14). On the other hand, upon the CPU 302 determines that the writing the data erroneously ends, the CPU 302 causes the control to proceed to a step SA16 (NO in the step SA14).

(57) In the step SA16, the CPU 302 reports that the maintenance operation erroneously ends, and ends the process shown in FIG. 8. The report is achieved, for example, by displaying on the monitor 314, a message indicating that the maintenance operation erroneously ends.

(58) In the step SA18, the CPU 302 writes, into the maintenance history storing unit 332, three types of information (A1 to A3) as shown below.

(59) A1) Executed content

(60) A2) Date and time

(61) A3) ID of PLC

(62) Accordingly, information on a maintenance operation is added in a history as shown in FIG. 6. A1) Executed content corresponds to the Content shown in FIG. 6. A2) Date and time corresponds to the Date and time shown in FIG. 6. A3) ID of PLC is an ID of the PLC 100 (an example of information identifying the PLC 100), and corresponds to the PLC shown in FIG. 6. The CPU 302 reads the ID of the PLC 100 from the nonvolatile memory 126 or other memories of the PLC 100.

(63) Next, the control is allowed to proceed to a step SA20.

(64) In the step SA20, the CPU 302 writes, into the control memory 160 of the PLC 100, three types of information (B1 to B3) as shown below, and ends the process shown in FIG. 8.

(65) B1) Executed content

(66) B2) Date and time

(67) B3) ID of support device

(68) Upon the information B1 to B3 is written into the control memory 160, information on the maintenance operation is added in a history as shown in FIG. 5. B1) Executed content corresponds to the Content shown in FIG. 5. B2) Date and time corresponds to the Date and time shown in FIG. 5. B3) ID of support device is an ID of the support device 300, and corresponds to the Device shown in FIG. 5. The ID of the support device 300 is stored in, for example, the HDD 308.

(69) <Maintenance Operation Executed by Support Device 300 (2)>

(70) FIG. 9 is a flow chart of another example maintenance operation process executed, for the PLC 100, by the support device 300. In FIG. 9, a process executed by the CPU 302 of the support device 300 is shown on a left side, while a process executed by the processor 122 of the PLC 100 is shown on a right side.

(71) First, a communication is established between the support device 300 and the PLC 100 (in steps S10 and S30). More specifically, for example, an operator inputs, into the support device 300, an instruction on a maintenance operation for the PLC 100. In response to this, the CPU 302 requests the PLC 100 to establish a communication. The processor 122 of the PLC 100 responds the request and establishes the communication between the support device 300 and the PLC 100.

(72) In a step S12, the CPU 302 sends information on maintenance to the PLC 100 to instruct the PLC 100 to write the information on maintenance. The information on maintenance is, for example, data specified in the support device 300 so as to be written into the PLC 100. The data is specified, for example, in an identical or similar aspect to data specified in the step SA12.

(73) In a step S32, the processor 122 receives the information on maintenance. Next, a control is allowed to proceed to a step S34.

(74) In the step S34, the processor 122 writes, into the nonvolatile memory 126, the information on maintenance received in the step S32. Next, the control is allowed to proceed to a step S36.

(75) In the step S36, the processor 122 reports to the support device 300 a result of writing of data executed in the step S34. The result to be reported is that, for example, the writing of data normally ends or erroneously ends.

(76) In a step S14, the CPU 302 determines if the result reported by the PLC 100 indicates that the writing of data normally ends. Next, upon the CPU 302 determines that the result indicates that the writing of data normally ends, the CPU 302 allows the control to proceed to a step S18 (YES in the step S14). On the other hand, upon the CPU 302 determines that the result indicates that the writing of data erroneously ends, the CPU 302 causes the control to proceed to a step S16 (NO in the step S14).

(77) In the step S16, the CPU 302 reports that the maintenance operation erroneously ends, and ends the process shown in FIG. 9. The report is achieved, for example, by displaying on the monitor 314 a message indicating that the maintenance operation erroneously ends.

(78) In the step S18, the CPU 302 writes, into the maintenance history storing unit 332, three types of information (A1 to A3) as shown below.

(79) A1) Executed content

(80) A2) Date and time

(81) A3) ID of PLC

(82) The information (A1 to A3) to be written in the step S18 is identical to the information (A1 to A3) written in the step SA18 (see FIG. 8).

(83) Next, the control is allowed to proceed to a step S20.

(84) In the step S20, the CPU 302 instructs the PLC 100 to write, into the control memory 160, three types of information (B1 to B3) as shown below, and ends the process shown in FIG. 9.

(85) B1) Executed content

(86) B2) Date and time

(87) B3) ID of support device

(88) The information (B1 to B3) instructed to be written, in the step S20, is identical to the information (B1 to B3) written, into the control memory 160, by the CPU 302 in the step SA20 (see FIG. 8).

(89) In a step S38, the processor 122 determines if the instruction is received. The processor 122 stands by until the processor 122 determines that the instruction is received (NO in the step S38). Next, upon the processor 122 determines that the instruction is received, the processor 122 allows the control to proceed to a step S40 (YES in the step S38).

(90) In the step S38, the processor 122 follows the instruction from the support device 300 to write, into the control memory 160, the information (B1 to B3), and ends the process shown in FIG. 9.

(91) <Maintenance Operation Using Recording Medium 500>

(92) FIG. 10 is a flow chart of an example maintenance operation process executed when the PLC 100 writes, into the nonvolatile memory 126, data stored in the recording medium 500. The process shown in FIG. 10 starts, for example, when an operator operates a start button (an example of the input device 132) of the PLC 100.

(93) With reference to FIG. 10, the processor 122 determines, in a step S50, if an SD memory card (recording medium 500) is attached to the SD memory card interface 136. Next, upon the processor 122 determines that the SD memory card is attached, the processor 122 allows a control to proceed to a step S54 (YES in the step S50). Upon the processor 122 determines that the SD memory card is not attached, the processor 122 causes the control to proceed to a step S52 (NO in the step S50).

(94) In the step S52, the processor 122 reports an error indicating that the recording medium 500 is not attached, and returns the control to the step S50. For example, the processor 122 turns on the LED 128 to report the error.

(95) In the step S54, the processor 122 executes a maintenance operation. More specifically, the processor 122 writes, into the nonvolatile memory 126, information on maintenance recorded in the recording medium 500. The information on maintenance is, for example, data of system firmware or an additional function recorded in the recording medium 500 so as to be written into the PLC 100.

(96) In a step S56, the processor 122 determines if the maintenance operation normally ends in the step S54. The processor 122 determines that, when writing of data normally ends in the step S54, for example, the maintenance operation normally ends. In addition, the processor 122 determines that, when the writing of data erroneously ends in the step S54, the maintenance operation erroneously ends. Next, upon the processor 122 determines that the maintenance operation normally ends, the processor 122 allows the control to proceed to a step S60 (YES in the step S56). Upon the processor 122 determines that the maintenance operation erroneously ends, the processor 122 causes the control to proceed to a step S58 (NO in the step S56).

(97) In the step S58, the processor 122 reports an error indicating that the maintenance operation erroneously ends, and ends the process shown in FIG. 10. For example, the processor 122 causes the LED 128 to blink to report the error.

(98) In the step S60, the processor 122 writes, into the recording medium 500 (SD memory card), three types of information (C1 to C3) as shown below.

(99) C1) Executed content

(100) C2) Date and time

(101) C3) ID of PLC

(102) Accordingly, information on the maintenance operation is added in a history as shown in FIG. 7. C1) Executed content corresponds to the Content shown in FIG. 7. C2) Date and time corresponds to the Date and time shown in FIG. 7. C3) ID of PLC is an ID of the PLC 100, and corresponds to the PLC shown in FIG. 7.

(103) Next, the control is allowed to proceed to a step S62.

(104) In the step S62, the processor 122 writes, into the control memory 160, three types of information (D1 to D3) as shown below.

(105) D1) Executed content

(106) D2) Date and time

(107) D3) ID of SD memory card

(108) Accordingly, information on the maintenance operation is added in a history as shown in FIG. 5. D1) Executed content corresponds to the Content shown in FIG. 5. D2) Date and time corresponds to the Date and time shown in FIG. 5. D3) ID of SD memory card is an ID of the recording medium 500 (an example of information identifying the recording medium 500), and corresponds to the Device shown in FIG. 5. The processor 122 reads, from the recording medium 500, the ID of the recording medium.

(109) Next, the processor 122 ends the process shown in FIG. 10.

(110) <Displaying Maintenance Operation History (1)>

(111) The CPU 302 can display, on the monitor 314, a maintenance operation history stored in the maintenance history storing unit 332 (see FIG. 6).

(112) In addition, the CPU 302 can display, on the monitor 314, a maintenance operation history stored in the control memory 160 (see FIG. 5).

(113) Further, the CPU 302 can display the maintenance operation history stored in the maintenance history storing unit 332 and the maintenance operation history stored in the control memory 160 in a combined manner. FIG. 11 is a view illustrating an example display in which a maintenance operation history in the support device 300 and a maintenance operation history in the PLC 100 are combined.

(114) The maintenance operation history shown in FIG. 11 includes Date and time, Device, PLC, and Content. The Date and time shown in FIG. 11 corresponds to the Date and time shown in FIGS. 5 and 6.

(115) The Device shown in FIG. 11 corresponds to the Device shown in FIG. 5. For a history of maintenance operations for the support device 300, values under the Device shown in FIG. 11 are PC.

(116) The PLC shown in FIG. 11 corresponds to the PLC shown in FIG. 6. For a history of maintenance operations for the PLC 100, values under the PLC shown in FIG. 11 are IDs of PLCs 100.

(117) In addition, in the maintenance operation history shown in FIG. 11, a number is assigned to each of the maintenance operations. Maintenance operations shown at 1 to 3 in FIG. 11 correspond to maintenance operations shown at 1 to 3 in FIG. 6. Maintenance operations shown at 4 and 5 shown in FIG. 11 respectively correspond to maintenance operations shown at 2 and 3 in FIG. 5.

(118) A maintenance operation shown at 1 in FIG. 5 and a maintenance operation shown at 1 in FIG. 6 are duplicated. Duplicate means that, for example, a maintenance content, a date and time, and an ID of a PLC 100 subject to the maintenance operation are identical. In this case, in an example shown in FIG. 11, the maintenance operation shown at 1 in FIG. 5 and the maintenance operation shown at 1 in FIG. 6 are indicated as a single maintenance operation (number 1 shown in FIG. 11).

(119) The CPU 302 can process a history as shown in FIG. 11 with a predetermined action. For example, the CPU 302 can extract, from the history shown in FIG. 11, information on a maintenance operation for a PLC 100 with a particular serial number.

(120) <Displaying Maintenance Operation History (2)>

(121) The CPU 302 can retrieve, into the HDD 308, a maintenance operation history stored in the control memory 160 of the PLC 100. In addition, the CPU 302 can display, when a recording medium 500 is attached to the SD memory card interface 316, a maintenance operation history stored in the recording medium 500 with a history stored in the maintenance history storing unit 332 and the history retrieved from the PLC 100 in a combined manner.

(122) FIG. 12 is a view illustrating an example display of a maintenance operation history when a recording medium 500 with an ID 2B63-3AA4 is attached.

(123) The history shown in FIG. 12 includes values identical or similar to values in items (Date and time, Device, PLC, and Content) in the history shown in FIG. 11. Maintenance operations shown at 1 to 3 in FIG. 12 correspond to maintenance operations 1 to 3 in FIG. 11. A maintenance operation shown at 4 in FIG. 12 corresponds to information on a maintenance operation stored only in the recording medium 500. A maintenance operation shown at 5 in FIG. 12 corresponds to a maintenance operation shown at 4 in FIG. 11.

(124) When a maintenance operation history stored in the recording medium 500 and a history stored in the maintenance history storing unit 332 or a history retrieved from the PLC 100 are duplicated in part, as shown in FIG. 12, the CPU 302 can display only either duplicated parts.

(125) A maintenance operation shown at 6 in FIG. 12 corresponds to a maintenance operation shown at 5 in FIG. 11.

(126) <Displaying Maintenance Operation History (3)>

(127) The CPU 302 can retrieve, into the HDD 308, a maintenance operation history stored in the control memory 160 of the PLC 100. The CPU 302 can further retrieve, into the HDD 308, a maintenance operation history stored in the recording medium 500 (ID 2B63-3AA4). Further, the CPU 302 can display, when another recording medium 500 is attached to the SD memory card interface 316, a maintenance operation history stored in the other recording medium 500 (ID 3C87-2EB5) with a history stored in the maintenance history storing unit 332 and the histories retrieved from the PLC 100 and the recording medium 500 in a combined manner.

(128) FIG. 13 is a view illustrating an example display of a maintenance operation history when a recording medium 500 with an ID 3C87-2EB5 is attached.

(129) The history shown in FIG. 13 includes values identical or similar to values in items (Date and time, Device, PLC, and Content) in the history shown in FIG. 11. Maintenance operations shown at 1 to 2 and 4 to 6 in FIG. 13 respectively correspond to maintenance operations shown at 1 to 2 and 3 to 5 in FIG. 12. A maintenance operation shown at 3 in FIG. 13 corresponds to information on a maintenance operation stored only in the recording medium 500 (ID 3C87-2EB5). A maintenance operation shown at 7 in FIG. 13 corresponds to a maintenance operation shown at 5 in FIG. 11.

(130) When a maintenance operation history stored in the recording medium 500, a history stored in the maintenance history storing unit 332 or a history already retrieved from the PLC 100 or the recording medium 500 are duplicated in part, as shown in FIG. 13, the CPU 302 can display only either duplicated parts.

(131) The above described embodiment can record, into the PLC 100 itself, a maintenance operation history for the PLC 100. Accordingly, with the support device 300, the maintenance operation history for the PLC 100 can be reviewed.

(132) The above described history can include a device recording data written into the PLC 100 in each maintenance operation (a support device 300 or a recording medium 500). Accordingly, a device involved in executing a maintenance operation can be identified.

(133) In addition, in a control system requiring an input of a user ID for executing a maintenance operation, a history can include information on a user who has executed a maintenance operation. Accordingly, a person who has executed a maintenance operation can be checked.

(134) The embodiments disclosed in this time are intended for illustrative purposes only in all respects, and should not be construed as restrictive. The scope of the present invention is indicated by the claims, not the above description, and intends to include all modifications and alterations within the scope of the claims and equivalent meanings and ranges.

DESCRIPTION OF SYMBOLS

(135) 100 PLC

(136) 122 Processor

(137) 124 Main memory

(138) 126 Nonvolatile memory

(139) 132 Input device

(140) 134 Connector

(141) 136,316 SD memory card interface

(142) 150 System firmware

(143) 160 Control memory

(144) 300 Support device

(145) 308 Hard disk

(146) 314 Monitor

(147) 330 Program storing unit

(148) 331 Data storing unit

(149) 332 Maintenance history storing unit

(150) 500 Recording medium