DAKOTA ULTRASONICS MMX-7 Operation Manual

Also see for MMX-7: Operation manual

Contents

DAKOTA ULTRASONICS MMX-7 Operation Manual Manual pdf 29 page image

25CHAPTER FIVESELECTING THE MEASUREMENT MODE5.1 The setup libraryThe MMX-7 contains 64 user configurable preset locations to store custom setups foreasy recall. These setups can be optimi zed for the user’s specific application needsand can also be stored on a PC and transferred bi-directionally using Dakota’s PCinterface software included with the instrument.The setups supplied with the instrument cover some of the more typical applicationscommonly used with this type of instrument. These setups can be recalled, modified,and overwritten to one of 64 setup locations. Therefore, these factory setups canalso be considered a good starting point to be modified for custom applications. ThePC software includes a default setup file that can be uploaded to the gauge at anytime to restore factory settings. However, it is recommended that the user considersaving modified setups to an empty location rather than overwriting the factory setupsin the MMX-7. Once again, these factory settings are excellent starting points forcustom setups.5.2 Which mode & transducer do I use for my application?High penetration plastics and castingsThe most common mode for these types of applications is pulse-echo. The MMX-7has been optimized for cast materials. Cast iron applications require 1 - 5MHzfrequencies, and cast aluminum requires a 10MHz frequency. Plastics typicallyrequire lower frequencies depending on the thickness and make-up of the material.Larger diameters offer greater penetration power because of the crystal size, fordifficult to measure materials.Corrosion & Pit Detection in steel and cast materialsUse pulse-echo mode whenever attempting to locate pits and flaws. Typically a5MHz transducer, or higher, will be used for these types of applications. Use lowfrequencies for greater penetration and use higher frequencies for better resolution.Thru Paint & CoatingsOften times users will be faced with applications where the material will be coatedwith paint or some other type of epoxy material. Since the velocity of the coating isapproximately 2.5 times slower than that of steel, pulse-echo mode will induce error ifthe coating or paint is not completely removed. By using echo-echo mode, the useris able to successfully measure through both, the coating and steel, and completelyeliminate the thickness of the paint or coating. Therefore, the steel can be measuredwithout having to remove the coating prior to measuring. Users will often use pulse-echo mode and echo-echo mode in conjunction when performing inspections oncoated materials.