Programmable logic controller (PLC) was produces for use generally in industrial environments. For different
control processes many input and output ports are integrated on PLC. In addition to this some communication
protocols which are being used in industrial application, are present on PLC. As a short description PLC is a micro
computer which has communication protocols, input and output ports to control and manage the processes or
systems (Çetin, R., 2005) . Figure 1 shows the basic internal structure of PLC.