Device for processing programmable logic controller program
The present disclosure provides a device for processing a programmable logic controller (PLC) program. In one embodiment, the device includes a storage containing PLC programs stored on a block basis, and a program block table defining storage locations of the PLC programs; and a controller configured: when a PLC program is modified during a PLC is operating, to determine a start address of a storage location where the modified PLC program is to be stored with referring to a block number of the modified PLC program, size information of the modified PLC program, and the program block table; and to store the modified PLC program in the storage based on the determined start address. According to the present disclosure, multiple users may simultaneously access a PLC and then may simultaneously modify PLC programs during the PLC is operating.
1. A device for processing a programmable logic controller (PLC) program, the device comprising:
a storage including a memory, wherein the storage is configured to store PLC programs stored on a block basis, and a program block table defining physical storage locations of the PLC programs; and
a controller including a hardware main processing unit (MPU), wherein the controller is configured to execute the PLC programs stored in the storage, wherein the controller is configured:
when a PLC program is modified while a PLC is operating,
to determine a start address of a physical storage location where the modified PLC program is to be stored with referring to a block number of the modified PLC program, size information of the modified PLC program, and the program block table, wherein the modified PLC program includes first and second modified PLC programs, wherein a block number of the first modified PLC program is greater than a block number of the second modified PLC program, wherein a start address of a physical storage location where the first modified PLC program is to be stored is determined by increasing a start address of a physical storage location where the second modified PLC program is to be stored, by a sum of sizes of PLC programs corresponding to block numbers between the block number of the second modified PLC program and the block number of the first modified PLC program; and
to store the modified PLC program in the storage based on the determined start address.
2. The device of claim 1 , wherein the program block table includes a block number corresponding to each PLC program and size information of each PLC program.
3. The device of claim 1 , wherein the start address of the physical storage location where the modified PLC program is to be stored is determined by summing sizes of all of PLC programs stored in previous blocks to the modified PLC program block.
4. The device of claim 1 , wherein when the controller receives the modified PLC program, the controller is configured to back up PLC programs having block numbers greater than a block number of the modified PLC program,
wherein after the modified PLC program has been stored, the controller is configured to re-store the backed-up PLC programs in the storage based on a start address of a next block to the modified PLC program block.
5. The device of claim 4 , wherein the start address of the next block to the modified PLC program is determined by increasing the start address of the physical storage location where the modified PLC program is to be stored by a size of the modified PLC program.
6. A device for processing a programmable logic controller (PLC) program, the device comprising:
a storage including a memory, wherein the storage is configured to store PLC programs stored on a block basis, and a program block table defining physical storage locations of the PLC programs; and
a controller including a hardware main processing unit (MPU), wherein the controller is configured to execute the PLC programs stored in the storage, wherein the controller is configured:
when a PLC program is modified while a PLC is operating,
to determine a start address of a physical storage location where the modified PLC program is to be stored with referring to a block number of the modified PLC program, size information of the modified PLC program, and the program block table; and
to store the modified PLC program in the storage based on the determined start address, wherein the modified PLC program includes first and second modified PLC programs, and a start address of a physical storage location where the first modified PLC program is to be stored is determined by increasing a start address of a physical storage location where the second modified PLC program is to be stored,
wherein when the controller receives the modified PLC program, the controller is configured to back up PLC programs having block numbers greater than a block number of the modified PLC program,
wherein after the modified PLC program has been stored, the controller is configured to re-store the backed-up PLC programs in the storage based on a start address of a next block to the modified PLC program block.
7. The device of claim 6 , wherein the start address of the next block to the modified PLC program is determined by increasing the start address of the physical storage location where the modified PLC program is to be stored by a size of the modified PLC program.