Increased control to the water industry

01Nov

Haigh Engineering Co Ltd has 50 years’ experience in helping water authorities control their waste water streams using inlet screens, as well as maceration and dewatering equipment. So when the company wanted to overhaul its control panels for wastewater treatment plants, it turned to Siemens Automation and Drives for a high technology solution that would increase control intelligence and functionality, ease fault-finding and reduce hard-wiring and assembly time

Haigh had moved away from programmable relays and had standardised on Siemens’ Logo logic controllers and low-voltage control gear approximately two years ago; so when the decision was made to bring the control systems “into the 21st century”, the option to use Siemens was a natural progression.

“We wanted to offer enhanced functionality from a control viewpoint,” says electrical contracts engineer Bob Dean. “The priorities were to improve the diagnostics capability and make the controls more intelligent, pushing the product ahead of the competition in terms of technology level.” With application support, Siemens helped Haigh reengineer two of its control panels, one for its control screen and maceration equipment, and the other for its liquid separator and lipactor plant. The solution proposed included high-function ET200S distributed I/O systems, IM151 header modules, Siguard safety modules, PROFIBUS DOL and reverse load feeders, TP170 touchscreen HMIs and SIMOCODE intelligent overloads. The SIMATIC
ET200S is a multifunctional distributed I/O station that can communicate over both PROFINET and PROFIBUS. Its benefits include: less hard-wiring thanks to integrated technologies; significant space saving in the control panel, up to 50%; and bit modular design. SIMOCODE (SIRIUS Motor Management and Control Devices) is a flexible, modular motor management system for constant speed motors, which implements all motor protection and control functions, determines operational, diagnostic and statistical data and organises the communication between automation system and motor feeder.

“The finished product is first class,” says Mr Dean. “We have no pushbuttons or pilot lights on the panel door anymore; it’s transformed the product. Customers can connect it to a PROFIBUS network and obtain information on the status of the plant remotely. If there is a problem, it allows the water authority to send the right kind of engineer to attend. Also, we are able to review the way we install equipment at the customer site, as the Siemens solution allows us to undertake far more manufacturing, assembly and testing at our factory. In addition, the inherent simplicity of the control panel and its components reduces the chance of
mistakes and hence our product reliability increases. It is the right sort of product to supply our customers.” Haigh, a 110-employee company based at Ross-on-Wye in Herefordshire, has now completed its first couple of new control panels, the first of which has been delivered to South West Water. With interest from other water companies also being expressed it seems the control panels are already set for success.

Haigh manufactures and supplies inlet screens and screenings handling plant to waste water treatment facilities. The company’s focus is on providing waste solids processes that reduce real whole life costs for users (water use, landfill use, operations and maintenance) ultimately to improve environmental performance, so this control system fits well within the company ethos.

“The finished product has exceeded our expectations,” says Mr Dean, “although there is scope to enhance it even further using Siemens equipment. For instance, in a fault situation it is possible for the panel to dial out to the mobile telephone of the relevant engineer.”