Modbus is a protocol that is widely used internationally, open to all users and supported by many manufacturers. Modbus/TCP was developed from it for use in modern networks. This protocol is now an open Internet draft standard that was introduced by IEFT (Internet Engineering Task Force), the organization for Internet standardization. This openness means that every manufacturer and user is able to use this protocol – a possibility that many leading manufacturers have already availed of. The increasing expansion of Ethernet communication into industrial areas as well as the office environment has extended the use of Modbus/TCP in every sector. Heterogeneous system landscapes are the typical areas of use.