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DATA ACQUISITION COMPUTER The Phoenix Instruments DAS (data acquisition system) for opac 20/20 opacity monitors is a year 2000 compliant system built on a Windows operating system, making information exchange with other computers simple. The systems two computers would communicate via a network connection. This system eliminates the need for a PLC. The DAS consists of two PC computers. A system file server computer with a printer and a removable hard disk. A viewer computer is installed in the control room for operator interface. The two computers are linked by an Ethernet network. Both computers are equipped with modems to allow external access, trouble-shooting, and service by Phoenix Instruments. The DAS gathers data from all of the opacity monitoring instruments in ten second increments. Data is cumulated in one minute averages and status assigned by available information. The data will be logged on the report generating computer in the office. The file server logs the one minute data and cumulate the data into six minute averages, as required using the valid data criteria. The one minute data and the compiled averages will be displayed on the screen of the computer. Color changes of the displayed data indicates status. Operators will be notified of faults by warning windows appearing on the data screens. Reason codes can be edited and added to data by keyboard editing. A separate screens will allow for updating of the system constants, such as calibration values and allow selective manual calibrations of the opacity monitors one at a time or all monitors at once. The server computer will also generate a calibration or daily report on demand. The viewer computer in the control room has the data and alarms displayed identically as the server computer and has the same access to reason encoding of limit violations. Access to each level of operation will be pass word protected. The file server computer will also compile the quarterly reports and generate a hard copy and electronic report to disk. At that time data will be archived to the removable hard disk. DATA BACK UP All of the one minute data from the opacity monitors is taken by the file server computer and stored on the removable hard disk along with the status. At the end of every day the files are copied to the removable hard disk drive with a 1 Gigabyte cartridge. The cartridge easily holds a full year of data. When the drive is full, it can be stored to meet the five-year requirement, and a new cartridge used. © 1999 Phoenix instruments Inc.
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