The overall scheme of the experimental system is based on the PC platform to develop the numerical control principle and system experimental device of the machine tool. It is mainly composed of parts: PC (host computer) mainly completes the establishment of the whole experimental environment and human-machine interface function, the interface board of the PC (lower position machine) Mainly complete fine interpolation, information forwarding, position sampling and experimental milling machine control; experimental console mainly performs status display (such as table coordinate position, stepping motor ring and tool change status), switch input and machine operation The input of the command, etc., can realize the numerical control machine tool and various operation inputs through the experimental console; the small experimental milling machine is mainly used to verify the correctness of the experimental results, and feedback the actual position of the worktable to the position loop through the displacement sensor to realize the closed loop position. control.

The experimental system consists of a PC platform selected in the design process of the PC platform and the lower computer interface board experimental device, and then an AT bus interface board is designed, which is equivalent to the fine interpolation board in the numerical control system. The hardware resources include: 4-way buffer circuit for transmitting command information between the upper and lower machines and interpolation results of each coordinate axis; for pulse distribution of stepping motor in open-loop numerical control system and fine interpolation in closed-loop numerical control system The lower-level circuit of the complementary function; the A/D conversion circuit for the actual position detection of the X, Y, Z coordinate axes in the closed-loop CNC system, the corresponding displacement sensor uses the inductive absolute displacement sensor; used for the spindle speed control in the numerical control system D/A conversion circuit; counter circuit for manual pulse generator (MPG) pulse counting and corresponding manual control functions. (Finish)

PAC HV/LV

CMC for Oil Drilling is also named PAC,poly anionic cellulose ether. PAC-HV, because of its high molecular weight, exhibits excellent non-Newton fluid property and can modify rheological property of slurries; PAV-LV, because of its low molecular weight, allows better water retention and is more resistant to salt and high temperature.