DataLogger Tips and Tricks
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Technical Notice Reference Version 1.01 Technical Note DataLogger Tips and Tricks 1. Overview This document intends to provide users with tips and tricks for using the DataLogger Server Plug-In. At this point, users should verify that the data source being used is supported. For more information, refer to DataLogger Option for KEPServerEX OPC Server. Logging Data Consumes Disk Space Both the amount of data and the frequency at which it is logged will quickly consume disk space. Users must be aware of how their logging choices impact disk space consumption. For example, in testing, Kepware Technologies used a wide data format to log 1000 points of data every 10 milliseconds. It took about three days to consume 5GB of disk space. Users that require data to be logged at this rate have no way to avoid this; however, most applications require much slower rates. Designing the DataLogger Project The best way to plan the design of a DataLogger project is to start by determining what will be done with the data being logged. Knowing this enables users to create data tables in the most optimized format and to use the Data Source Names (DSN) and DataLogger project to populate tables accordingly. For example, a user that intends to log product data by shift (in order to generate a weekly production report) would create a table with records for Shift #, Up Time, Down Time, Parts Produced, Parts Rejected, and Date/Time Stamp. The following database design websites are recommended for more information. Five Simple Database Design Tips Tips on Database Design and Use Optimizing Data Logging DataLogger’s threading model can be tailored to suit users’ specific needs. DataLogger interprets each DSN as a queue to create a new logging thread. For example, if “LogGroup01” uses a DSN named “MySQL_ONE” and “LogGroup02” uses a DSN named “MySQL_TWO,” then DataLogger will generate two distinct logging threads even though both “MySQL_ONE” and “MySQL_TWO” may point to the same database. If “LogGroup01”

Technical Notice Reference Version 1.01 and “LogGroup02” both use “MySQL_ONE,” they will take isochronous (or equal opportunity) turns processing data. This scalability allows users to log tens of thousands of points simultaneously. This example created two log groups that both logged to distinct DSNs pointing to the same MySQL database. Logging was completed at approximately 50,000 columns per second. Important: Having more than one DSN connection to the same data source increases the chance of one connection locking the data table in order to insert a record while another connection also...

Technical Notice Reference Version 1.01 when DataLogger detects a request to create an “SQL_TIMESTAMP” column in an MS-SQL database, it will post a warning to the Event Log and override the column type (substituting “SQL_DATETIME” instead). Error Handling – Database Full Each data source will have a slightly different error response when the database is full. KEPServerEX will post a message to the Event Log indicating that the RecordSet could not be queried. It is recommended that users monitor the “_DataLogger.._Error” Tag from their OPC client application to see when an error has...