Gearbox failure in modern cooling professional fan arrangements utilised on CCGT power stations is common. Trending of vibration levels on the gearbox enables plant engineers to plan inspection and maintenance of the fan assembly. Providing shutdown protection in the event of excessive vibration is also a key requirement for minimising damage in the event of blade failure. Sensonics' DN2601 dual vibration monitor fulfils both these requirements at EGAT's Wangnoi manufacturers of power plant in Thailand. A single DN2601 industrial monitors each fan in combination with ICP type manufacturers of accelerometers, providing warning and shutdown alarm facilities in combination with 4-20mA process signals fed to the plant wide DCS for trending.