2. A method of communication between a peripheral equipment and a programmable logic controller executing high-level language program, and controlling devices, the method comprising: transmitting, by the peripheral equipment, a request for data read or data write related to a target device among devices controlled by the programmable logic controller, the request including a name of the target device that is not supported by the high-level language program; receiving, by the programmable logic controller, the request transmitted by the peripheral equipment; reading, by the programmable logic controller, 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 said name of said target device that is not supported by the high-level language program and reading from or writing to the determined physical address.
4. The method of claim 2 , 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 the 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.