BP refinery in Ohio, USA
56 000 euros saved thanks to wireless connections

Reliable data transmission through wireless connections

BP operates numerous refineries in the USA. Engineers and technicians started a pilot project on the site in Ohio to find out whether a reliable wireless data transmission is possible in an environment that is exposed to extreme noise emissions.

The application

The objective was to avoid high cabling costs that arise due to storage tanks located at large distances from each other.

High-voltage cables with strong interference fields lie near the spark gaps. Their effect on the transmission quality needed to be examined. Additionally aggravating was the fact that the oil tank sites do not have their own power supply.

The pump determines the level using ultrasound

A remote groundwater pump was selected as the test object. Here, the level had to be measured and, once a limit was reached, an alarm given off.

The pump uses ultrasound to determine the level and converts it into an analog signal. When the upper limit value is reached, a threshold value switch also generates a digital alarm signal.

Solution

Wireless transmission systems by Phoenix Contact

A wireless transmission system from Phoenix Contact was installed on the pump. This enabled I/O data to be acquired wirelessly in the field and the information to be forwarded to a control system via an RS-232 interface.

Up to eight analog and digital extension modules can be connected per station, and can thus be selected accordingly for the respective application. On the control side, information from one (point-to-point) or several (multipoint-to-point) field stations can be evaluated via a Modbus protocol.

Up to 255 field stations can be operated on one master. All hardware is supplied self-sufficiently via a solar system with solar panels, battery and charge controller.

Summary

The wireless connection worked remarkably reliably in this environment subjected to strong interferences.

The cost-efficiency advantage was also analyzed: The cabling of the system would have involved digging up the ground to lay cables over a length of approximately 700 meters. BP assumed a cost of approximately 80 euros per meter in this specific case. Overall, it was possible to save more than 56 000 euros.

After the positive tests, the BP Group has integrated the wireless transmission system from Phoenix Contact into the production facility at Ohio River. A total of 16 crude oil tanks were equipped with wireless technology at the plant.