Peripheral device of programmable controller, method of variable substitution, and computer program product thereof

A peripheral device of a programmable controller for converting a first program into a second program including a code using a variable, the peripheral device comprising:

• an extracting unit that extracts an address from the first program;
• an assigning unit that assigns a unique variable to the address;
• a creating unit that creates correspondence information on correspondence between the address and the variable based on classification of the address;
• and
• a substituting unit that substitutes the address with the variable based on the correspondence information to convert the first program into the second program.

A method of variable substitution for converting a first program into a second program including a code using a variable, the method comprising:

• extracting an address from the first program;
• assigning a unique variable to the address;
• creating correspondence information on correspondence between the address and the variable based on classification of the address;
• and
• substituting the address with the variable based on the correspondence information to convert the first program into the second program.