Abstract: A programmable logic controller performs execution of a program in each set period and repeats the execution of the program. The first device storage stores a device value that is an input value and an output value of the program. The second device storage stores the device value stored in the first device storage in a previous period. In a case in which a reading target preset for a device designated by a monitor request received from an engineering tool is the first device storage, the command processor reads the device value stored in the first device storage after execution of the program in a current period is completed, and in a case in which the reading target is the second device storage, the command processor immediately reads the device value stored in the second device storage. The command transmission/reception element transmits the device value to the engineering tool.

Abstract: A programmable logic controller performs execution of a program in each set period and repeats the execution of the program. The first device storage stores a device value that is an input value and an output value of the program. The second device storage stores the device value stored in the first device storage in a previous period. In a case in which a reading target preset for a device designated by a monitor request received from an engineering tool is the first device storage, the command processor reads the device value stored in the first device storage after execution of the program in a current period is completed, and in a case in which the reading target is the second device storage, the command processor immediately reads the device value stored in the second device storage. The command transmission/reception element transmits the device value to the engineering tool.

Abstract: A control device includes a storage unit that stores a program, a program execution unit that executes the program stored in the storage unit to control a device to be controlled, and a backup execution unit that stores, at the start of a backup operation of the program currently being executed, the program, information for identifying a location currently in execution in the program, information for identifying a location currently being held in the program, and operation data, in a backup storage unit.

Abstract: A programmable logic controller executes an SFC program including a plurality of blocks, each including a step indicating an operation output and a transition indicating a transition condition. The programmable logic controller includes an SFC device data collecting unit for collecting device data of a device included in an active step for each scan at the time when the SFC program is executed, an SFC device data storing unit for storing the data collected by the SFC device data collecting unit, and an SFC device data outputting unit for outputting the data stored in the SFC device data storing unit to a memory card as a file for each of the steps or the blocks.

Abstract: A control device includes a storage unit that stores a program, a program execution unit that executes the program stored in the storage unit to control a device to be controlled, and a backup execution unit that stores, at the start of a backup operation of the program currently being executed, the program, information for identifying a location currently in execution in the program, information for identifying a location currently being held in the program, and operation data, in a backup storage unit.

Abstract: A programmable logic controller executes an SFC program including a plurality of blocks, each including a step indicating an operation output and a transition indicating a transition condition. The programmable logic controller includes an SFC device data collecting unit for collecting device data of a device included in an active step for each scan at the time when the SFC program is executed, an SFC device data storing unit for storing the data collected by the SFC device data collecting unit and an SFC device data outputting unit for outputting the data stored in the SFC device data storing unit to a memory card as a file for each of the steps or the blocks.