Li Kejian

Design of ARM-based human-machine interface of plastic injection blow molding machine

This paper designs a plastic blow molding machine monitor system which takes ARM7 embedded processor as core and takes CAN bus as communication system. By analyzing the Human-machine interface system requirements, hardware use LCD screen, touch screen and keyboard as man-machine interface display and input device, use the LPC2478 with ARM7 microprocessor, large capacity memory and CAN communications interface circuits as man-machine interface control device. In software design, firstly μC/OS-II embedded operating system is transplanted to the ARM core to achieve real-time multi-task switching. Secondly μC/GUI is transplanted to display graphics and text. Write man-machine interface application program task-units. Finally LPC2478 connects with CAN bus controller CTM8251T to achieve communication between the modules. The injection blow molding machine embedded human-machine interface is completed.

Design of PLC timer system based on FPGA

Aiming at the design of the small PLC timer system, based on the analysis of operational characteristics of PLC timer and the process of PLC user timer program and the data transmission requirements of PLC user program execution module and the timer, a method which applies the FPGA Parallel algorithm to designing small PLC timer system, is presented. The timer system is composed of clock generator unit, timing unit, timing control unit and the chip select circuit. While the timer runs at the speed of 1ms timed pulse, the operation of timer is translated into the operation of RAM memory cell which is made up of FPGA. That makes user can operate on RAM memory cell instead of the timer, and it just take up a few execution time of PLC user program. This paper introduces the theory and structure of the FPGA timer system, the state transition diagram of timer control module, the timing diagram of user program execution module operating on timer, finally take an experiment and gives analysis of the results.