Wire Diameter Measurement System.,

A study on the backward diameter measurement system of wire rod has been done in the thesis. Using the photic law of refection and the property of lens, the light intensity of the reflected beam on the focal plane of a lens is proportional to the diameter. Through measuring the light intensity, we can get the diameter of wire rod. After analyzing the factor of error in the previous experiment, we use two photocells to measure the intensity of source light and signal light. To eliminate the influence of the instability of the source light radiator, divide operation is done after some processing of the photocell signals, such as: I/V converting, amplifying, and low pass filtering, etc. Under the control of the sensitivity-controlled circuit, the circuit module of digital displaying shows the result of divide operation. The influence of the fluctuating reflective ratio of the wire rod can be reduced by the integral effect of photocell, and the integral operation through software is avoided. Not only the equipment is simplified, but also the error is reduced.By the system, we can get a mini-instrument of measuring the diameter of wire rod, which can dynamically measure the diameter of metal wire rod, non-contact and on-line. The instrument has many merits, such as: quickly measuring, low equipment cost, conveniently installing, and having slight influence of vibration, etc. So the instrument can be used in these situations: having severe influence of vibration, installing inconveniently, not very precision. And the system has the value of further research and development.