Handling Data Received with Timestamp in the Future

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The color of text in the ClearSCADA system indicates useful information about the state of the object. In older versions of ClearSCADA (prior to ClearSCADA 2005 R0), yellow indicated Future Data. From ClearSCADA 2005 R0 and later, the Future Data Color in the color palette has been modified to use blue to better contrast with a white background.

Future data is defined as data that is received by the ClearSCADA server, that lies outside of the allowable time range. This time range is configured in the Server Configuration dialog. By default, data that is ahead of the current time by up to 72 hours will be marked with a quality of future data. Data outside this window is discarded.

There are a number of reasons why the data could be marked as future data.

• If the time configured in the outstation reporting the time-stamped data is in the future. Many protocols support time synchronization between ClearSCADA and the outstation. Consider using this functionality. For details on whether the protocol supports this or how to use this functionality, refer to the relevant Driver Guides in the online help.

• The outstations may be configured to use local time while ClearSCADA uses UTC or vice versa. The obvious solution here is to ensure that the outstation and ClearSCADA use the same time base. This could also occur when the channel is in eavesdrop mode for those protocols that support eavesdropping.

It is generally recommended to configure outstations to operate on UTC time. This means that all outstations have a common time base regardless of their location and the influence of daylight savings.

If the problem is related to data being into the future by the UTC offset amount, once the problem is resolved, for some protocols there will be a period of time where current data values will not update since ClearSCADA has a current value timestamp that is more recent than the values being returned by the driver. Time stamped data from the outstation will still be entered into the historian, but values on mimics will not update until the difference between UTC and local time has expired such that the current time is now in advance of the PC time.

As an alternative, the current data files can be deleted. This will remove the current values and timestamps of all points in the database and so current data values will begin to update again immediately.
Note that this will also delete other runtime values such as operator notes and so should be done only if necessary.

Look for the ClearSCADAData.dat files in the Data path (see System Configuration - Location in the server configuration tool for the location).



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