Research And Manufacture Of Electronic Micrometer With Three-Color Led Bargraph Display

The electronic micrometer with the LED bargraph display is widely used in measuring the position and shape tolerances or dimension tolerances of mechanical parts. But the instrument at home has the deficiency of lacking of digitalization, few intelligent functions, no alarming over tolerances, less extending capability. The instrument can't meet with the demanding efficiency of the modern enterprise production detection because it can't detect the tolerances of the parts quickly.Against to the problem of the current instrument, the system used the technology of sensor, automatic acquisition, communication and computer and adopted the design philosophy of modularization, generalization and standardization. We developed this there-color LED bargraph display measuring instrument which can measure the dimension and runout tolerances of mechanical parts. The instrument has four input channels which can be combined at discretion by software, five digital ranges for measurement, tolerance zone controlling, two displaying mode and the function of networking measurement. The general idea of the system design is as followed. The sensors transform the not-electric signals to electric signals, and which are sent to the data acquisition model. The digital signals dealed with singlechip are sent to the LED and LED bar, and then compared with the tolerances which are set by user. If the detection values are beyond the limited, the LED bar gives an alarm of different color to improve the efficiency of measurement.The system of hardware using the fully integrated 12-bit data acquisition system (ADμC812) and CPLD as the LED bar drive circuit to simplify the hardware design and enhance the stability of the hardware. The system of software offers the framework of the function extensibility and the instrument upgrading with the menu operation. At last, we design the serial communication protocol which is high efficiency of data transfer and high performance of fault tolerant to connect with personal computer through the bus of RS-485. Also we develop the software of PC to manager the instrument and collect real-time measuring data with network and realize the user interface. The date of measure...