The MSM, of modular conception, is made up of three units :

1) the data acquisition unit which comprises: a roughness sensor ( contact or non-contact ), an amplifier unit to condition the signal obtained on the sensor , an Analog / Digital Converter board (ADC). 2)the displacement unit, which allows displacement and positioning of the sample surface under test, comprises : two step-by-step crossed stepper motors, a power unit to amplify the motor driving signal, a Stepping Motor Controller board.

3)the central processing unit, which controls data acquisition and their exploitations, exists under two material and software MSM configurations :

© a PC compatible under Windows system.

User-friendly, allowing 2D and 3D data acquisitions. This configuration has the following functions :

• least squares fitting,

• low and high-pass filtering,

• roughness parameter calculation,

• high resolution printing for 3D maps.

Its program allows :

• - quick 3D statistical and frequential analysis,

• - access to specific descriptive measures,

• - measurement of fractal dimensions,

• - richer data bases.