HART actuators for cogeneration plant

Louise Smyth

Forming the interface between valves and control systems, electric actuators play a decisive role when it comes to efficient and safe operation of power plants. In addition to their primary task of opening and closing valves, actuators frequently take over the task of transmitting secondary information to the control system. Typically, this includes both device information and plant operating data for diagnostic and maintenance purposes.

As an alternative to fieldbus protocols, the simple and robust HART protocol is becoming more and more popular for transmitting this type of secondary information. By modulating an additional signal onto the basic 4-20mA analogue signal, HART allows simultaneous transmission of additional field device data, thus combining the advantages of both fieldbus and conventional wiring.

A recent example is the Pengerang cogeneration plant currently under construction in Malaysia. AUMA has supplied more than 350 HART-equipped electric actuators for the four cogeneration units to be built on the site. The gas-fired power plant forms a key part of the Pengerang Integrated Complex (PIC), a prestigious scheme run by Malaysia’s state-owned petroleum corporation, Petronas. The power plant is expected to generate up to 1,220MW of electricity as well as up to 1,480 tons per hour of steam for other plants within the complex. Support for HART was one of the key actuator requirements for this project.

AUMA supplies Electronic Device Descriptions (EDDs) for its HART-equipped AC 2 actuator controls for integration with interpreters such as Siemens Simatic PDM, Emerson AMS, and Emerson 475 Field Communicator. Following device integration in the interpreter, the actuators’ most important parameter and diagnostic information is available without additional programming.

In addition to wired and WirelessHART, AUMA provides electric actuators for parallel communication and for all widely used fieldbus standards. Industrial Ethernet solutions using Modbus TCP/IP and PROFINET are also available.

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