The purpose of this Bachelor's thesis was to examine the ability to use PLCopen XML for-mat to transfer the programmable logic controller project between different program devel-opment environments. The capability to transfer PLC projects between program develop-ment environments would facilitate the administration and the reducing the number of pro-grams.

It was possible to find three program development environments with PLCopen XML sup-port. The first was CoDeSys V3.5 made by 3S-Smart Software Solutions GmbH and the second is TwinCAT 3 from Beckhoff Automation GmbH. These two program development environments are supporting PLCopen XML schema version 2.0. The third was Multiprog 5.50 from Phoenix Contact Software GmbH with the support of PLCopen XML schema version 1.0. The different kind of IEC 61131-3 compliant PLC projects were exported from development environments in PLCopen XML format. These PLCopen XML files were checked and imported to all development environments.

CoDeSys and TwinCAT development environments worked similarly and the test results were almost identical. CoDeSys and TwinCAT environments are not able to import PLCo-pen XML files from Multiprog environment. Multiprog is not either able import PLCopen XML files from other development environments.

The reason why CoDeSys and TwinCAT -environments are so identical is because Twin-CAT is based to CoDeSys V3 environment. Multiprog programming environment is not PLCopen XML compliant with others because it supports schema version 1.0 and there is some errors in that programming environment. However, there is hope that the PLCopen XML support is expanding to also other programming environments, because on October 2014, work is started to get PLCopen XML as the part of standard IEC 61131.