The Design And Implementation Of The Modem Of A Well Data Acquisition System

In the process of oil resources exploitation,the under-well temperature,pressure and other parameters are needed to be monitoring in real-time in order to fully learn the underground information.This paper uses the underground DC supply cables as a channel.The real-time under-well information is monitored utilizing the power line carrier technology to build a data modem module of well spread-spectrum data acquisition system.The paper discusses the characteristics of the power transmission are first,and simulates its channel characteristics.Power line carrier technology implements data transmission using spread-spectrum communication.It has anti-jamming and anti-decay properties,so in this paper this tech is chosen to be the focus.This paper develops a communication data modem on the basis of the power line carrier.The system’s hardware is consisted of the SSC P485(spread spectrum communication chip),PIC18F(microcontrollers)and a power line coupling circuit.In the coupling circuit,the electromagnetic coupling and the resistance-capacitance coupling combination is combined to implements coupling and separation of the power line signal(50Hz)and the spread spectrum signal.Meanwhile,the communication reliability of the system is further improved employing error-correcting codes in software design.In this paper,the system hardware and software is designed and debug.It is also proved that the modem is reliable in data transmission through a 1,200 meters power lines down to underground in laboratory conditions.