Computer engraving machine interface circuit structure

And electrical characteristics of the motor according to the execution of PC parallel port configuration, determine the input and output of the circuit, solve the pulse points, positive &negative, signal feedback, current set format, such as matching problem, completed the design of interface circuit, the interface circuit principle as shown in figure 1. Figure 1 yifan, computer engraving machine interface circuit schematic circuit design of interface circuit according to the performance parameters of the stepper motor, selected the corresponding drive chip THB7128, peripheral circuit design, such as number, dial the code switch set subdivided driving current set end VERF voltage size and size of an external sense resistor Rs. Interface circuit and the output of the PC MACH3 port 25 pins parallel links up, including positive &negative, pulse input, and two stage circuit isolation, noise, etc. Module 1: parallel DB25 stitching connection. Interface board with PC parallel port interface DB25 needle pin connection diagram is divided into three signal input, output, and undefined pins. 2-25 needles 9 needles and 14 pin is the output signal, the pulse and direction of the motor and make the control pin, corresponding control motor speed, direction and enabled. Module 2: motor driver chip THB7128 and connection. Motor driver chip and coil connection, as well as drive chip driver parameter value set of corresponding circuit, including the fine fraction, and drive current, chopping frequency, etc. Module 3: travel limit switches and abrupt stop button. Module 4: manual control module. Artifacts on the knife or trial cut, need the next bit machine through the button to try a knife or cutting, for technical personnel, improve efficiency. 555 pulse generator through an external shift, with adjustable frequency pulse, in cutting tool in three directions can obtain different feed speed. Module 5: the power supply. 220 v ac DianZhuan into more stable direct current. Module 6: spindle dc motor PWM speed control. In a circuit to add a frequency and duty ratio adjustable PWM control circuit, one can zoom in and fly-wheel circuit, make the speed of the spindle motor adjustable within a certain range. Engraving machine price information in yifan numerical control network.