3. A programmable logic controller that executes high-level language program for controlling devices, the programmable logic controller comprising: a request receiving unit which receives a request for reading or writing related to a target device among devices controlled by the programmable logic controller, the request being transmitted by a peripheral equipment and including a name of the target device that is not supported by the high-level language program; a symbol table reading unit which reads a symbol table to determine a physical address in a memory of the programmable logic controller related to the target device, wherein the symbol table defines a physical address in the memory of the programmable logic controller for each of the name of the target device that is not supported by the high-level language program; and a physical address reading or writing unit which reads from or writes to the determined physical address, wherein the programmable logic controller comprises at least one hardware component.
3. A programmable logic controller that executes high-level language program for controlling devices, the programmable logic controller comprising: a request receiving unit which receives a request for reading or writing related to a target device among devices controlled by the programmable logic controller, the request being transmitted by a peripheral equipment and including a name of the target device that is not supported by the high-level language program; a symbol table reading unit which reads a symbol table to determine a physical address in a memory of the programmable logic controller related to the target device, wherein the symbol table defines a physical address in the memory of the programmable logic controller for each of the name of the target device that is not supported by the high-level language program; and a physical address reading or writing unit which reads from or writes to the determined physical address, wherein the programmable logic controller comprises at least one hardware component. 5. The programmable logic controller of claim 3 , wherein: the request includes the name of the target device, and the symbol table defines a relationship between a name of each of the devices, a variable name corresponding to said each of the devices and used in the high-level language program, and the physical address in the memory of the programmable logic controller corresponding to the variable name.