Sync Engine tab

The Sync Engine tab contains settings for miscellaneous Synchronization Engine parameters and options.

Note: The settings on this tab apply to all registered interfaces, not just the selected interface.

Check for New Connectors

The box in the Check for New Connectors area contains the number of seconds that the Synchronization Engine pauses at the end of each iteration of the main scheduling loop. See Synchronization scheduling. When the Synchronization Engine is idle, this setting controls how often the Synchronization Engine checks for newly registered interfaces, if any interfaces have been unregistered, or if a synchronization scan needs to be performed for any registered interface.

The value chosen for this pause time is a compromise between responsiveness to immediate synchronization requests and reducing the frequency of searches for newly registered or unregistered interfaces. Increasing the pause time makes the Synchronization Engine less responsive to immediate synchronization requests, but decreasing the pause time increases CPU usage on the PI APS system and load on the PI Servers.

Milliseconds to Pause between Interface Point Group Sizes

During a synchronization scan, the Synchronization Engine executes two loops. In both loops, each iteration calls a method in the PI APS Connector for a group of points, processes the returned values, and then pauses before performing the next iteration. The box in the Milliseconds to Pause between Interface Point Group Sizes area contains the number of milliseconds that the Synchronization Engine pauses after processing the results for a group of points in both loops. Configuration of group sizes is discussed in APS Connector tab.

The value chosen for this pause time is a compromise between elapsed time for a synchronization scan and competition with other applications on the same computer for CPU cycles. Decreasing the pause time decreases the elapsed time for a synchronization scan (although the effect may be too small to notice). Increasing the pause time takes the Synchronization Engine out of contention for CPU cycles for longer periods, which lessens the impact that the Synchronization Engine can have on other applications on the same computer. For additional discussion of the how this setting affects Synchronization Engine performance and resource usage, see Synchronization in PI APS.

Point Log Format

The option buttons in the Point Log Format area select whether optional point logs are created and their format.

Note: This setting is a global choice for all registered interfaces.

The main reason for creating optional point logs is to use them to manage PI points with other tools, specifically piconfig or PI Tag Configurator. The optional point logs in piconfig format are also very useful for troubleshooting. Unless you plan to use the optional point logs after every synchronization scan, creating them adds unnecessary overhead to every synchronization scan. Select Do not create point logs to prevent the Synchronization Engine from creating optional point logs.

If you only need point logs occasionally, consider using Export on the Tools menu instead of enabling the optional point logs. See section Export Points to File dialog box. Exporting in Excel format produces essentially the same workbook as a point log in Excel format. Exporting in comma-separated value (CSV) format is similar, but not identical, to a piconfig script. For someone familiar with piconfig, using a CSV export file as a piconfig input file is not difficult. Another method for obtaining a piconfig script is to export in Excel format, then use the PI Tag Configurator export facility to create a piconfig file.

Note: Use the following options only if you must have point logs from every synchronization scan.

Select the PIConfig format button to cause the Synchronization Engine to create the optional point logs and indicate that they be formatted as piconfig scripts. Separate piconfig scripts are created for existing points that require attribute changes, deleted points, and available points.

Selecting Microsoft Excel XLS format causes the Synchronization Engine to create the optional point logs and indicates that they should be formatted as Excel workbooks.

Note: Excel must be installed on the PI APS node to use this selection.

The Synchronization Engine automates Excel to create the optional point log workbook. This option was implemented before Microsoft issued a notice that automation of Office applications was not supported from non-interactive clients, like the Synchronization Engine. See Microsoft Knowledge base article 257757. Therefore, OSIsoft discourages the use of this option.

After a synchronization scan completes, the export to Excel workbook feature in the PI APS Configuration utility can be used. See Microsoft Excel format in Export Points to File dialog box.

This option can noticeably increase the time to execute a synchronization scan and the load on the PI APS computer. A single Excel workbook is created that contains separate worksheets for existing points that require attribute changes, deleted points, and available points. Also, a piconfig script is created that contains the necessary digital state additions and edits.

Note: Before selecting Excel format for the optional logs, confirm that the number of existing points and available points is less than the maximum number of rows supported by Excel on a worksheet.

Startup Delay

The Synchronization Engine can be configured to delay from 0 to 32767 seconds after startup before loading the PI APS Connectors. For some data source applications, loading or calling data source DLLs or programming interfaces (API) before the data source application enters an operational state can cause the data source application to fail or the data source application can return incorrect information. When a PI APS system is restarted, this option gives data source applications time to reach a fully-operational state before the first synchronization occurs.