Control System Of Mechanical Properties Nondestructive Testing Prototype Of The Full-size Wood Composite Panels Based On Virtual Instruments

Full-size Wood Composite panels is the most common in production and sales at both home and abroad, its size is 2.44x1.22m.Traditionally, the mainly way of the full-size wood composite panels detection is use big specimen cut into small specimen, then taking destructive testing for small specimen, according to a number of small specimens of the average value to evaluation the mechanical properties of the big specimen.How to test the mechanical properties of full-size wood composite panels quickly, nondestructively and developed the useful testing equipment is a critical problem in Wood Composite panels production and quality control process.This thesis is mainly study the control system of mechanical properties nondestructive testing prototype of the full-size wood composite panels. Mainly working content is as follows.(1)On the basis of confirmed the testing prototype motion control requirements, we design two sets of the scheme:the control system based on the Virtual Instruments, and the control system based on the Virtual Instruments and PLC. This paper studies the first plan primarily.(2)Make the hardware selection. On the basis of extensive research, we chose the NI PCI-7344 motion controller card, NI UMI-7774 Terminal block, NI USB-6210 data acquisition card, Delta servo motor, Delta PLC and HollySys stepper motor.(3)For the first set of control scheme.To explore the effective connection between the different hardware, set the related parameters of the servo motor, and we studied the mode of NI motion controller how to control the servo motor, we concluded the three kinds of control mode, Analog mode, Open collector mode, Differential mode, and chose the best control mode.we studied how to make use of software programming to control servo motor, the paper introduced how to make use the NI MAX panel to simple control servo motor, and use Lab VIEW software programming to control servo motor. In the process of using LabVIEW programming we make good use of LabVIEW state machine architecture.(4)Solved the other key problems of the control system, it mainly involves the excitation device back to zero, how to control the stepper motor and so on. Use the capacitive proximity realized the stepper motor zero detection. For stepper motor control, group skillfully use the timer terminal of data-acquisition card to generate pulse signal, the DO terminal of data-acquisition to generate TTL signal, use this method we control the excitation stepper motor successfully.(5)Refer to the second control scheme based on the Virtual Instruments and PLC, emphasis expound the communication problems between data-acquisition card and PLC. Using high speed isolation convert module, it can level matching and photoelectric isolation, make the 5V signal from data-acquisition card converts 24V signal, which can recognition by PLC.