INSTRUMENTATION & CONTROL 4. DCS overview. The DCS upgrade can be visualized as consisting of three layers. The field terminal cabinets retained their original WDPF card-edge connectors and field device wiring. A central application/automation server was added that communicates with the HMI user interfaces in the control room via redundant Ethernet cables. Thin client workstations connect to the server using a web interface. Courtesy: Siemens Power Generation 5. Quick cabinet retrofit. The existing field termination cabinets were stripped and restocked with new control hardware, significantly reducing the time required for the retrofit. Electrical & Controls Engineer Scott Fowler noted that a new optical cable was run across the plant to link all the remote cabinets together with the control room. Source: POWER plant's unique needs. Siemens duplicated the dozens of existing graphical screens of the human-machine interface so well that it took a sharp eye to recognize the differences. Many additional graphic monitoring and alarm screens on 24-inch monitors were added once the operators became familiar with the significantly increased capabilities of the T3000 DCS (Figure 3). Field hardware upgrades began with Siemens technicians removing all the old cards and then stripping the remaining equipment from the cabinets, with the exception of the original card-edge connectors and card-edge connector wiring. The hardware upgrades were configured such that the new processors, I/O, and other PROFIBUS modules could be used in conjunction with the original card-edge connectors to minimize wiring changes from the field instrumentation to the cabinets. The new I/O modules were tied to the original field wiring by plugging the existing card-edge connectors onto a Siemensdesigned interface card. A subcontractor simultaneously ran the new cabling between cabinets and the control room and all the (thin client) HMI control stations. A web browser installed on each thin client provides the user interface hosted by the DCS Application Server. Each management, maintenance, operation, or engineering station has a view of all aspects of plant control and monitoring, although access can be determined by role. SPPA-T3000 applications are hosted by a fault-tolerant application May 2012 | POWER server with a dual-redundant architecture that eliminates single points of failure and safeguards data integrity (Figure 4). With the field wiring updated and new Structural Bolting 101: torque isn't tight (what?) tension is! use Squirter DTIs to ensure proper bolt tension. ® the best way to bolt! 1 800 552 1999 abt. power april:Layout 1 3/2/12 11:57 AM Page 1 See why torque isn't tight! Scan with smartphone. www.powermag.com info@appliedbolting.com www.appliedbolting.com circle 34 on reader service card 57 T R A I N I N G * F I E L D S U P P O R T * T E C H N I C A L E X P E R T I S Ehttp://www.appliedbolting.com http://www.powermag.com