Development Of USB Interface Of The Portable Surface Roughness Tester

The portable surface roughness tester carries out accurate measurement of product surface roughness at workshop or calibration department. The system operation is easy. And the tester is small and light. It's very suitable for work site use. Along with technical development, there are some weak in the data processing and data management. Aim at the place of these shortages, improve the portable surface roughness tester. This article redesigns its electrical circuit, and use the USB to make the tester and the computer communicate. In order to consummate its function and make it oriented the needs of the market.In this paper, development state of surface roughness measure system and measurement principle are briefly introduced, architectural configuration and communication protocol of the USB are analyzed. Based on all of these, the paper designs the hardware and software about the portable surface roughness tester electrical circuit and USB interface in detail.The hardware of the system is made up of TMS320VC5402 as main processor, at the same time designs the circuit of the power and the input and output and so on. At last use MAX3420E as USB interface pin to design the interface electrical circuit.The software of the system has three portions: The first portion is firmware, including USB communication control; the second is USB driver, which is the channel between the firmware and computer application; the third is application to test the function of the system based on PC, which is used to process and manage data.According to the experiment, the portable surface roughness tester which is improved carry out the function which is expected, make up the original product weak and consummate it.