Grating Data Acquisition And Error Correction Technology

With the development of modern processing and measurement technology, it has putforward higher demands for the accuracy of displacement measurement and processingpositioning. In many displacement measurement technique, the grating displacementsensor with its stable performance, high precision, anti-interference ability, andcombined with computer conveniently, etc., is widely used in the field of CNCmachine tools and machining. Based on JCXF series grating, a grating data acquisitionand error correction system with USB interface was developed in this paper, thesystem had the advantages of high measuring precision, convenient to use,miniaturization and so on.The grating signal processing system was achieved by using a combination ofhardware and software mode. The microcontroller LPC11U14as the core of the wholesystem was responsible for controlling and coordinating work among the variousmodules. The hardware part used the CPLD chip EPM570T144C5for processinggrating signal and achieving four subdivision and identifying direction of grating signal,reversible counting etc.The software part included: microcontroller read grating subdivision number fromCPLD; using cubic spline interpolation algorithm fit error curve in microcontroller,and corrected error for any interpolation point; Developing USB driver,so that USBcan success enumeration and achieved the communication between microcontrollerand PC; writing PC display interface etc..By experimental verification, the design achieved grating signal four subdivision,and the grating measurement system resolution reached to1μm, the error corrected ofmeasurement system was reduced from-16.8μm~23.5μm to-1.2μm~11.6μm, themeasurement system accuracy had significantly improved.