In order to reduce the price for, and improve the performance of automatic control systems for magnetization of synchronus generators, the possibilities of using a PC based software PLC system, Programmable Logic Controller, has been investigated. The result is a system based on the CoDeSys software PLC with runtime environment from 3S-Software, communicating with external units via Modbus fieldbus. System price is reduced from €5000 to €2000 and system processing speed is reduced from 10 ms for a Siemens S7 PLC to 4 ms with the CoDeSys PLC system though unsolved problems with runtime seizure caused by improper settings in the PC BIOS.