Aracruz Uses a Dynamic Simulator for Control System ... - Andritz

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STAGING THE DCS AND THE SIMULATOR Initial Plan During the course of Simulator staging activities in each process area, three important steps stand out: 1. Mapping of DCS/Simulator inputs and outputs (I/O Mapping); 2. Verification of the individual control loops; and 3. Verification of the EPC operating procedures and final validation of the process models (the Joint – FAT). Foxboro Activities 1st SaveAll AMEC Simulator Staging Activities Foxboro Pre - FAT (CP Hardware) Duration : Variable I/O Mapping Personnel : AMEC, Si ndus Duration : 1 week 2nd SaveAll Fox App SW Fox App SW Foxboro FAT (CP Hardware) Duration : Variable IDEAS Mini - Sys te m IDEAS Mini - Sys te m Activities : build cross - reference database, finalize I/O addresses , I/O communications check Modifications to Fox App SW Initial System - W ide Check Preparation for Final Joint FAT Activities : Individual control loops and motor start - stops tested tes ted , Foxboro App SW & model pre - check , controller pre - tuning Personnel : AMEC, Si ndus , Aracruz Operator Duration : 1 week 3rd SaveAll Fox App SW IDEAS Model Figure 6 Initial Information and Workflows during Staging Final SaveAll (CP Hardware) Fox App SW Final SaveAll (FSIM Softwar e) IDEAS Mini - Sys te m Joint Fox App S W FAT Activities : Area - wide start - up & shutdown witnessed by EPC Supplier & Foxboro , group starts tested ; changes made to Foxboro App SW Personnel : AMEC, Aracruz, Foxboro , EPC Supplier Duration : 1 week At the onset, we developed a diagram, which describes the flow of information and activities of the Simulator in relation to DCS staging. It is shown as Figure 6, below. To support this work process and the proposed schedule, we also developed three so-called "mini-systems". These systems were hardware abbreviations of our final system architecture, but they were able to run the same software for a single area. Later in the staging process we developed techniques to allow the staging of two areas using a slightly modified mini-system. www.andritz.com 8 of 16
DCS/Simulator I/O Mapping On the Simulator side, the first step executed is the mapping into the system of all DCS inputs and outputs. In this step, each I/O device in the process model and the matching entities in the DCS configuration must be aligned. The product of this activity is called the "Cross-Reference Database". The model developer accomplishes this activity, as the onus is on him to match the DCS system, not the other way around. The modeler needs only support from a DCS technician in obtaining an appropriate SaveAll. At this stage, the DCS configuration does not have to be a highly developed one. With his Cross-Reference Database assembled, the model developer could appear at staging perhaps three days before the finish of the conventional DCS contractor’s FAT, for a final pre-check of process model-DCS communications. Control Loops Verification After the construction of the Cross-Reference Database, the Simulator team is ready to begin the verification of configuration coding. In this step, the model developer must have the support of a DCS technician, for adjustment of control parameters. He also needs an experienced console operator to run the Simulator and the DCS contractor’s configuration coder, for correction of mistakes in the configuration that might impede the continuity of the checkout work However, if a more integrated procedure were to be used, we feel that a "control configuration ready for Simulator staging" must at a minimum be complete (no areas marked “to come”), including all features such as group starts and sequencing. It also must be pre-checked to the best of the coders´ ability. Extending conventional staging too long is a questionable use of resources. However, coming into staging without a complete control configuration is an even worse waste of resources. As soon as the console operator starts to execute the start-up, shutdown and emergency procedures of the plant, the real business of Simulator staging starts. Using ever more advanced SaveAlls (configuration loads) from the DCS side, individual control loops were tested, by trying to start the area. Motor start/stops also were tested and controllers pre-tuned. The work might seem to have been relatively routine, but it was made more complex by the existence of three types of possible “deviations”; deviations in the process models themselves, in the logic underlying the DCS control strategy and in the DCS configuration coding. Every deviation, or potential improvement, was logged on a formal, so-called, “punch list”. On the Mill “C” project, punch lists were augmented daily and delivered to the DCS coder for correction of outstanding items in the course of his work. As well, the coder might be asked to make emergency corrections of items blocking the progress of Simulator staging work. For each new EPC area, the Simulator had to prove to the uninitiated that it was a potent tool. In this regard, the punch lists became the focus. Either the items on it were valid, or they were not. The alternative of the EPC signing off on staging before the Simulator was employed soon became passé. As soon as the Simulator was used, mistakes that conventional checking methods could not find were revealed. As the work proceeded, it also became necessary to make modeling corrections or changes. Often, the changes made to the models were not to correct mistakes; they were more often aimed at achieving the desired process response, to accomplish training objectives. The demands on a model for staging are somewhat lower than for training, but step-wise changes were considered, and often made, to prepare the Simulator for training. The net effect was a higher fidelity Simulator for both purposes. www.andritz.com 9 of 16
Page 1 and 2: Aracruz Uses a Dynamic Simulator fo
Page 3 and 4: A simplified view of the overall ar
Page 5 and 6: Worksheet Building - Featuring a Mo
Page 7: Washing calculations: ( 100 C) C DF
Page 11 and 12: Simulation Company 18% Figure 7 Ove
Page 13 and 14: 4) DCS Staging using the Simulator
Page 15 and 16: OBSERVATIONS AND CONCLUSIONS The Si

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