Design And Realization Of Absolute Linear Optical Encoder Adjusting And Testing Instrument Software

Absolute linear optical encoder is a new type of foreign encoder products that appeared in the market in 2005.Compared with the incremental linear optical encoder,the absolute encoder is directly get the current position information after power supply without the need of "zeroing" operation.Also,simplified the design of the control system,using the half-duplex serial communication technology,reliable communication and so on,bring the absolute encoder more and more widely used in the numerical control industry.With the widely application of the absolute encoder,in order to let the user more convenient to diagnose the working performance and malfunction of the absolute encoder.Besides,in order to more convenient for the optical encoder manufacturers in the production procedure to test the encoder performance,diagnose malfunction,adjust the internal photoelectric parameters.So,this requires a kind of adjusting and testing package for on-line diagnostics and adjustment.As the study of the absolute encoder started late in China,there is no absolute encoder adjusting and testing product,but foreign HEIDENHAIN and Renishaw have the corresponding adjusting and testing products.In this paper,on the basis of the existed absolute encoder adjusting and testing products and the absolute encoder products in China,carried out demand analysis of the absolute encoder adjusting and testing product,confirmed the specific function of the designed encoder adjusting and testing instrument.The main work of this paper is to design the upper computer system of the absolute encoder adjusting and testing instrument,including the design of the data acquisition device and the software design of the host computer.The function of the data collector is the medium that communicates with the host computer as the absolute encoder.For the entire diagnostic system control,the data collector is subject to the host computer(the program on the PC)instructions to communicate with the absolute encoder.Its main controller uses the field programmable gate array(FPGA),the hardware circuit comprises an absolute interface circuit,FPGA control circuit and USB communication circuit.The data collector uses the high-speed processing capability of the FPGA to instantiate the Bi SS IP core provided by i C-Haus to communicate with the absolute encoder,control the analog-to-digital converter to acquire the incremental cosine signal,and control the USB communication module to communicate with the PC.The function of the upper computer diagnosis instrument software is used as the man-machine interface for the user to carry on the fault diagnosis of the absolute encoder,used the Lab VIEW platform to design the display and control interface.First,according to the functional requirements of malfunction diagnosis,divided into 26 command modules.Then defined the communication protocol between the PC and data collector,when the host computer command issued,the data collector receive it and will translate data to the PC after implements the corresponding command.Finally,the function module of the absolute encoder adjusting and testing system is debugged,the whole system collect,transmit,display and control function are tested.The test results show that the designed adjusting and testing system for absolute encoder can complete the diagnostics and the internal photoelectric parameters adjustment work.