A programmable logic controller (PLC) system is provided. The programmable logic controller (PLC) system divides a memory region into a plurality of regions according to a function, and reads or transmits data from or to the divided regions according to an operation mode to be performed, wherein the plurality of regions obtained through division includes: a first storage region storing log data on the PLC system; and a second storage region storing a hyper text markup language (HTML) file.