PROFIBUS HELPS WITH UK FLOOD CONTROL
Two concrete towers stand 20 meters above the ground at the UK Environment Agency’s Dartford Barrier Flood Defence System in Kent, England. The barrier is routinely closed in conjunction with the bigger Thames Barrier upstream to prevent high tide water in the River Thames flowing back up the creek and flooding Dartford and the surrounding area.
Two steel gates each 30-metre across and weighing over 160 tons each, are suspended between the towers and are lowered onto the river bed to block the flow of water. Together they can hold back 10.4 meters of water. The drive system comprises two 18.5kW pump and motor units. It is envisaged that the barrier may need to operate an average of 50 times per annum over the next 25 years. “The system has to be highly available with many fallback systems in case of failures,” said Andrew Garwood, a Senior Contracts Manager in the Controls Division of Qualter Hall & Co Limited, Barnsley.
Much of the equipment the control system spoke to was PROFIBUS- or Siemens-based. Two PROFIBUS Master communication modules (MVI56-PDPMV1) from ProSoft Technology were installed inside ControlLogix PACs to facilitate communications. “The ProSoft Technology modules were utilized to provide PROFIBUS DP into the ControlLogix rack and permitted four separate PROFIBUS DP segments for redundant operation,” Garwood said.
Fiber optic cables were installed between the two towers during the overhaul. ProSoft Technology 802.11 Industrial Hotspot radios served as the fallback link. ProSoft Technology’s solutions helped ease the engineering work by making it possible for the ControlLogix system to communicate over a single protocol. The system allows data to be reviewed quickly, centrally and remotely, providing convenience when accessing diagnostic information. Thousands of homes and businesses are now safely protected.