The Step Motor System Controlled By The Single-chip Microcomputer In The Document Detector

With the scholars’ study of document detection technology in recent years, this technology has been improved greatly, but the document made time detection is influenced by many factors, so this technology still has a lot of difficulties. This technology plays an important role in a variety of disputes. The document made time detector which is used for the document made time detection and is called document detector for short, has been widely used.The document made time can be detected by adding a certain amount of chemical reagent to the document and analyzing the phenomenon after the reaction. In this paper, the step motor control system based on single chip microcomputer can be used in the liquid injection control system of the document detector. The step motor can transform the received digital pulse signal into linear displacement or angular displacement, and it has good positioning accuracy. On the other side, there are many advantages to control the step motor by the single chip microcomputer, such as accurate output pulse, real-time and flexible function, and it can also simplify the hardware circuit, reduce the cost and improve the reliability of the system. Thus when the step motor control system is used in the document detector, it can realize the precise control of the amount of the chemical reagent, the accurate location of the liquid injection device as well as the exact adjustment of the objective and the turntable.This paper introduces the step motor control system systematically, including the selection scheme demonstration, the design and the debugging of all the modules. The system is mainly composed of man-machine interface module, serial communication module, main control module, six controlled modules, six drive modules and six motors. It can add a certain amount of chemical reagent to the detection position of the document accurately by the step motor control system.The man-machine interface is designed by the VC++6.0software. The main control module selects the P89C669, which is made by Philips Company, as the microcontroller, and it realizes the receiving, analysis and sending of the instructions by the design of the hardware and software. The controlled module chooses the P89LPC922made by Philips Company as the microprocessor, and it realizes the communication with the main control module and the receiving and sending of the instruction. The serial communication module is designed by the MAX232chip, realizing the conversion of the TTL standard level and the EIA standard level. The motor drive module is designed with the L289N chip, receiving the control pulse of the controlled module and driving the step motor running.Finally, through debugging function modules and the data communication between function modules, it proves that the system can control the motor running state precisely, so as to ensure that the document detector can adjust injection, objection and turntable accurately.