Research And Development Of Multi-channel Patrol Inspection And Control Instrument

Due to the single-chip computer technology developing rapidly, the instrument industry is progressing in same speed. The structure of instrument is changing from the structure of single and inflexible function to multiple, flexible, intelligent, digital and networked functions. So the instrument designed with modern technology have more functions, simpler hardware, stronger anti-interference and easier operation. And they have very strong competing for market.The research method for a multi-channel patrol inspection and control instrument is introduced in this paper. The instrument is composed of PIC16F877, which is single-chip computer as a hard-core of the instrument, signal conversion part, LED display, keyboard, relay output control part and analog output part etc. The instrument has the transforming and handling function for variety input signals, auto and manual measurement conversion and display function, exceed limit (upper limit and lower limit) alarming indication function, exceed limit alarming control function and analog output function.The characteristics of multi-channel patrol inspection and control instrument are shown as follows:Part hardware functions are realized by software.The design of software is modularized.Parameters setup and modification is simplified and real-time.The hardware platform is universal.The key technology solved in the design of multi-channel patrol inspection and control instrument is shown below:The hardware and software design for various input signals conversion and process. The hardware makes sure the circuit is universal for different signals. The software ensures to setup a proper amplifying for different signals.Anti-interference design: The power design removes the interference from power supply. The watching-dog solves the program that program run away. The software filte improve the reliability of signal measurement.Communication technology: Communication protocol design ensures free of error code transmition between single-chip computer and PC.Communication useing makes the instrument parameters setup and modified be simplifier.Ensure measurement accuracy: The hardware design makes sure the measurement accuracy of input signal. The software design ensures the A/D conversion accuracy.