Reengineering of the PLC-Technology for an Oil Storage Facility


Project description

The automation system of the whole facility has been redesigned using Siemens S5-controls and a DOS-based visualisation system to utilize the state-of-the-art Siemens process control system PCS 7. As well as operating the facility via eight 19" monitors for the visualisation (OS), it can also be controlled via illuminated pushbuttons from the control room or via on-site operation.


Oil storage facility (aerial view 2005)

Network for PLC and visualisation  

This challenging task was planned in-house, programmed and commissioned on-site without a shutdown of the facility, according to customer requirements.

Control system

The PCS7 system consists of an EN/OS and two more OSs. The 417-4H CPU is connected to a PC via CP443-1 and a switch. The communication protocol used is “Industrial Ethernet”. The ET200 stations are connected to the CPU via the fieldbus system Profibus DP. Profibus PA is used for connecting pressure measuring devices in ex-proof areas.
Long distance Profibus connections are realized with fibre optic cables connected to optical link modules (OLM), which are linked to the copper Profibus cable.

Monitoring by failsafe PLC

Another important feature is the safety concept. Higher-ranked safety functions are realized as a failsafe programme within the CPU. The failsafe hardware modules integrated into the periphery allow modular upgrading of safety relevant functions like the emergency-stop.

Display of error messages and temperature development


The visualisation allows an overview of the whole facility. Current states of electrical equipment, such as pumps or motor-operated valves, are displayed using variable colours. Important information, which is available in the controls, is collected, formatted, archived and partially visualised. The archived data includes error and status messages, drive operating hours as well as their actual currents.

Visualisation oil storage facility

Why HIT?

HIT have successfully completed this project. A clear user interface was designed for the operators and a good software structure has been achieved. From the very beginning, this system has proved its reliability. These features have increased the failsafe performance and the productivity of the system.