Design And Implementation Of Petrochemical Materials Loading And Unloading SCADA Control System

Petrochemical companies use a variety of transportation ways to meet the rapid development of oil and basic chemical raw materials, such as pipeline, shipping, rail, and truck transportation. In order to overcome the disadvantages of the manual operation, reduce environmental pollution, improve operational efficiency and increase the enterprises performance of storage management to meet the needs of economic development, we need highly-automatic, safe and reliable loading distributed control and management systems.This paper is to design a SCAD A system to meet the requirements of materials automatic trasportation. We implement the system functions of remote interlock control and data monitoring through selection of hardware and programming of software.According to the project requirements, this paper chooses E+H batch control device, mass flow meter, oil spill electrostatic protector, combustible gas alarm device, temperature meter, pressure meter and IC card reader to realize the control and monitoring function of the system and business process.This paper chooses the ControlLogix PLC of Rockwell Company to meet the control requirements of the loading and unloading automatic system. The paper uses ST and LD programming language of PLC by programming software RSLogix5000to realize the control function, including valve switch control, pump frequency PID control, compressor switch control, automatic unloading process control, the2to1selection of batch control device redundant signal, process parameter control and display, etc.This paper uses iFIX as the PC monitoring platform to develop a Human-Machine Interface (HMI). According to the project requirements, the HMI is to achieve eight different process control interfaces of on-site loading and unloading process. It also provides other functions, like historical data query, alarm display, etc.This paper uses industrial Ethernet and Modbus fieldbus protocol for SCADA system information exchange. And it adopts OPC technology to solve the problem of data communication among monitoring system and PLC. It makes the monitoring system as OPC client to collect information from the controller as OPC server. Consequently this paper implements control and management integration of the transportation system.