Industrial Automation Controller PCB Board Recovery specific characteristic is the repair amount is large, but the types of circuit boards to be repaired are small, the maintenance staff will even record the normal values of such data in detail for reference.
A large number of PCB circuit board maintenance practices have shown that this detection method is not only effective in the hands of experienced personnels, but also often the only repairing method available when there is no circuit board schematic drawing and can’t be tested online.
However, this method has obvious limitations
In fact, the resistance measured with a multimeter refers to a current value corresponding to 15V (multimeter battery voltage). It means that there is only one point on the voltage and current plane. For circuit nodes with linear characteristics, the current values at all other voltages can be calculated from this point (of course, care must be taken within the operating voltage range);
However, this can‘t be done for circuit nodes that exhibit non-linear characteristics. This means that the current value at 15V is within the correct range and does not guarantee that the current value at other voltages will also be within the correct range. The solution is to take a few more points, such as 16 points, 32 points, 64 points or more.
Double values range from negative to positive including the entire working electrician range. When the points taken are dense enough, a curve is formed, and the fault is judged by the degree of coincidence of the entire curve rather than the degree of coincidence of one point. Obviously much more intuitive and comprehensive. This is the technical principle of the so-called port “Analog signature analysis“, which is customarily called “VI curve test”
