Generally speaking, in the numerical control measurement, as a bridge connecting the probe and the computer, the following requirements must be met. The filtering function must be provided, because the electromagnetic interference phenomenon is inevitable in the actual application site, and the filtering circuit on the interface board is to interfere with these interferences. Clear or reduce to the least extent. Must have analog-to-digital conversion for effective communication with the computer. The counting function must be available because the amount of deformation of the probe is dictated by the number of pulses. An interface circuit to the computer must be provided for the computer to sample. Of course, different interface boards should be used for different probes. Since one-dimensional inductive probes are used, only the corresponding interface board circuits are introduced. The sum is a sine wave signal, and after being shaped by a zero-detection circuit, it becomes a square wave as shown in the figure. At this time, the basis of computer sampling has been laid. Since the square wave from the zero-crossing detection circuit is too rough and the square wave is quite similar to the forest, it cannot meet the requirements of the profiling measurement, so the waveform is required to be subdivided, and the square wave equivalent is reduced. This is done here with a quadruple frequency circuit. After the waveform is subdivided, the square wave is equivalent to the determination of the direction of the offset of the probe. It can be realized by judging the relationship between the zero-crossing detection circuit and the two signals. If it is detected first, the probe is in the positive direction. Offset, otherwise the probe is offset in the negative direction. Of course, the relationship with the offset direction is artificially set and can be set in the opposite relationship. (Finish) sewer cleaning machine sewer cleaning machine ZHEJIANG BOTUOLINI MECHANICAL CO.,LTD , https://www.botuopump.com