When turbines are being serviced on the testing station at the Italian firm, they are powered up to an astonishing 70,000 revolutions per minute. With numbers as high as these, the consequences of exceeding maximum thresholds are almost frightening.
Contec automated the first testing station for the Italian partner as far back as 1988 and selected Rockwell Automation as its supplier of control technology. To ensure the worst-case scenario never happened, further safety shutdown components were added, these easily integrated into the Rockwell Automation control system.
The repeated nature of the testing process and specific rules that govern it, allowed Contec to break from the convention of using two systems - automation to control the generator units and metering to capture measurements - and combine them into a single device. This makes testing simpler and more cost-effective.
Further bottom line savings were achieved by removing the need for the system to undergo an annual external recalibration process through the inclusion of an internal calibration function. This was especially important as the customer stipulated a very high level of measurement accuracy (several decimal places) when most solutions did not support floating-point arithmetic - the numbers after the decimal point. By working together, CONTEC and Rockwell Automation devised an integrated metering system which imports, logs and analyses all the measurements to the required level of accuracy.
After 23 years of excellent operation, the company decided to upgrade the control system in 2010, from PLC 5 to its successor Allen-Bradley ControlLogix PAC (Programmable Automation Controller) to allow testing of additional types of APU. The migration process, conducted by Contec, only took a few days due to the conversion functions included in the RSLogix 5000 programming tool which allowed the program transfer to be 90% automated.
Like the PLC 5 before it, the Allen-Bradley ControlLogix PAC can handle floating-point arithmetic. This is essential for the customer, who needs to run parabolic approximations with multiple data points on the equipment it tests.
The important factors in the product selection process include the right blend of technical performance, proven quality, affordable prices and investment security. The new ControlLogix family's extremely fast CPUs and straightforward scalability and connectivity, backed up by fast global support from Rockwell Automation, also impressed Contec and acted as key decision criteria.
Safety shutdown components have a particularly important role to play in ensuring generator units which are defective do not become damaged beyond repair during testing. "It's not unusual for a testing engineer to disable the electronic rotation speed limit if he wants to check the last speed threshold", says Gunter Tiefensee, CEO of CONTEC GmbH. "This could be dangerous, so we have implemented a further safety device that cuts off the fuel supply within a fraction of a second if a certain rotation speed is exceeded."
To facilitate data management, Contec has included Rockwell Automation's FactoryTalk Historian SE data capture software that logs measurements from the entire testing area and delivers a consistent data history. FactoryTalk VantagePoint is used to remotely visualise and generate reports on the data; helping to extend the engineer's reporting and diagnostics options.
For further information please visit: www.rockwellautomation.com
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|Title Annotation:||Problem Solver; Contec GmbH|
|Publication:||Plant & Works Engineering|
|Date:||Oct 1, 2012|
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