Design Of Computer Monitoring And Controlling System Based On PLC In High Temperature And High Pressure Experimental Station

As an important downhole tool in oil and gas exploration industry, the safety of HTHP logging equipment is of vital importance in high-temperature and high-pressure deep(HTHP) well. A safety test on HTHP logging equipment is accomplished by simulating the HTHP environment by a HTHP experimental station. Combined with the requirements of HTHP experimental station, a monitoring and controlling system is designed in this thesis to monitor and control the ATHP/HTHP testing process in real-time, which successfully changed the current manual control and low-level automation status.Firstly, combined with the monitoring requirements of HTHP experimental station, the requisite functions including screen-display, real-time communications, data storage and alarm should be available in the expecting monitoring and controlling system. The overall design of the monitoring system is established using the combined PLC and IPC control program after ascertaining the Centralized control system as selected control mode.Secondly, with the requirement of selection principles of PLC hardware and control requirements of monitoring and controlling system, its hardware configuration is determined to the Siemens S7-200 series PLC CPU226 CN as the core controller. The wiring diagram of the PLC hardware, the electrical design of CPU module and expansion modules are acquired. The Advantech industrial computer control system is selected as the host computer, the connection between host computer and the PLC hardware is established finally.Thirdly, A PLC control program using ladder as the programming language based on the process of experimental station is developed by the Siemens programming software STEP 7-Mirco/WIN, which can achieve the manual and automate control of the experimental process. A human-computer interaction interface is designed using KingView software with the functions of real-time monitoring, data displaying, data storage, data reports and trend curves printing.With the on-site installation and commissioning, the control and data acquisition program of the designed system have met the requirement of experimental station and has been used in a high temperature and pressure test stations with a stable running performance to achieve the desired results.