Designing an Integrated Alternative
Delivering an easy-to-use system with this breadth of scope meant that ECT needed to use an automation technology that leverages open-architecture standards.
The company found just that in the modern PlantPAx®DCS from Rockwell Automation. The PlantPAx technology is based on open-communications standards and can serve as a common automation platform by connecting process, discrete, power, information and safety control.
For the turbomachinery applications, ECT used the PlantPAx system to provide a SIL 2-rated platform for compressor control. The hardware leverages add-on instruction capabilities and delivers execution speeds that are equal to or better than proprietary systems. ECT also incorporated its patented, state-of-the-art, surge-control software, which uses algorithms to help detect and prevent potentially damaging surges in the compressor. Integrated HMI software from Rockwell Automation was used for the operator interfaces.
“We also incorporated load-sharing as another critical application in the turbomachinery control system,” Stoll said. “The compressors work together to maintain a constant discharge pressure for the compressor network. Load-sharing also allows the customer to bring individual machines on-line or off-line to accommodate changing demands without disturbing the overall process.”
For the auxiliary systems, ECT used the AADvance® fault-tolerant control system from Rockwell Automation to provide a SIL 3-rated hardware platform for sequencing and process control for the auxiliary skids, and for system trips.
“If the lube-oil system quits or if cooling is lost on the motor, the AADvance platform can trip the system and stop it before damage occurs,” Stoll said.
As part of the integration of the turbomachinery, auxiliary control and condition monitoring systems, the open-platform solution also provides a single connection to the plant distributed control system (DCS) via Modbus/TCP.