Spectrum Communications recently commissioned a fully redundant scada system on the John Ross tugboat using Adroit scada software and Tele-Flex I/O interface unit to perform the monitoring of this vessel.
The Adroit scada monitors two powerful V16 engines that run in parallel to make the John Ross one of the 10 strongest tugboats in the world. The Adroit scada also monitors the exhaust engines and exhaust manifold temperatures alerting the crew via the scada's alarm functionality when they operate at critical levels. Close attention is also paid to the combined RPM, torque, drive shaft and bearing temperatures inside the engines both fore and aft.
Spectrum Communications' sales manager, Kevin Clack, says, "Spectrum Communications expertise and products were chosen to perform this high profile project as the previous system had become unreliable with no back-up. Spectrum Communications and Adroit Technologies are South African-based manufacturers. Because of this, we were able to eliminate the previous lack of product support to the John Ross."
One of the more unusual challenges that Spectrum Communications faced was in the set-up of the fuel tank monitoring. The challenge was in monitoring liquid levels that are affected by the rolling motion of the sea. The SI used Visual Basic scripting to put delays on the tank alarms, ensuring that an alarm will only sound after it has been active for a certain period of time. In this way, crew can be certain that levels are truly critical, and false alarms caused by the constant ocean fluctuations are eliminated.
Tight security was implemented on the workstations to protect it from tampering and avoiding system malfunctions - as the scada is integral to the operation of the tug. The chief engineer's office has a remote Adroit node for viewing and access to the main system. Script files were created so that operators could change alarm ranges under different operating conditions.
Two Adroit workstations are employed because of the cluster server configuration ensuring redundancy of the system. A touch screen and mimics were designed so as to avoid the use of a mouse - making the system more intuitive and easier to operate under extreme sea conditions.
The mimics drawn on the scada are actual replicas of the engine, exhaust and boat layout, therefore making it easy for operators to locate and attend to faults from a centralised point. Alarms are audible via sirens fitted throughout the tug. Adroit's trending functionality is used for reference purposes aboard the vessel. It shows all eight exhaust temperatures on one trend screen.
The difference in power output of the engines has to remain within a prescribed limit and an alarm sounds to warn when one is working harder than another. Engine components are monitored to ensure that the load is being evenly shared. Using the trending function, operators can see how temperatures vary over time and can use this information to determine overall equipment efficiency, as well as to implement preventative maintenance on gaskets and other parts that are running too hot.
The John Ross also has four alternators that generate power for the whole vessel. All the temperatures and pressures of these alternators, exhaust temperatures, oil pressure, cooling water pressure and temperatures, etc, are also monitored.
The system also monitors various other functions such as speed, winding temperature, sea temperature, steering, gears, purifying of oil, seal integrity, micro floats (used in many of the tanks to gauge oil), water, air pressure for the pneumatic systems, status of domestic fridges, and the sewage plant. Clack says "This project's successful implementation has already, and will continue in the future, lead to similar projects for Spectrum Communications and Adroit Technologies."
For more information contact Megan Davidson, marketing, Adroit Technologies, 011 658 8100, [email protected], www.adroit.co.za
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| Fax: | +27 11 658 8101 |
| Email: | [email protected] |
| www: | www.adroit.co.za |
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