European Journal of Scientific Research (ISSN: 1450 ... - EuroJournals

© European Journal of Scientific Research, Vol 7, No 5, 2005
2.2.2 Amplifiers
The purpose of these apparatuses are to convert the electric charge delivered by the turntable into
an electric tension proportional by taking account of the sensitivity of the sensor (N/V), justifying
the choice of the range of measurement.
2.2.3 The conversion chart PA300
During the measurements, the amplifiers deliver an analogical signal. To be treated, then
recorded, this signal will be sampled at an Eigen frequency insufficiently high and equal to 35
KHZ on each way.
Figure 1: Acquisition of the signal
This chart is equipped with a connector for 62 poles to be directly inserted in a slot of the
microcomputer.
2.2.4 Reading of measurements
The Reading of measurements was possible following a writing of a program facilitating the
introduction of the following data : range used on amplifier charge, the depth of cut, length of
the workpiece, width of the test-tube (thickness of the panels), type of tool used, rotational
frequency of the tree, direction of cut, way of measurement (Fy in our case) opposed to the
advancing movement of the sample. After each test of workability, the graphic visualization gives
us the value of the average cutting pressure, the time of measurement, the number of peaks
(figure 2).
7