If one or more of the table columns has been modified to not allow null values in the field data will be buffered to the Store and Forward directory if the data quality of a tag to be logged is bad.
There are 2 solutions to resolve this conflict.
1. Change the field definition back to Allow Nulls. First check with the database admin to why it was change to not allow null values in case there is a downstream report depending on the data.
2. Enable the property Discard Null Rejects under the Database tab of the logging group.
Create Table and Fields
If the table or field added is not automatically created in the database verify that Create Table and Fields is enabled under the Database tab of the logging group.
If setting up logging to a table that already exists verify that the either all of the fields are correctly defined with the right data type or the fields that are not being logged to allow null values.
If one or more database triggers is defined to a table note that the logging rate and reliability will be impacted by the trigger's ability to complete.
If data is not being logged or slow to arrive in the database with no System Error reported check the table in the database engine if there are Triggers defined. If there are Triggers check with the database admin if the triggers can be removed or revised to complete quickly and reliably.
Note: If you need the Triggers to fire disable the bulk insert logging by setting the property Records to Enable Bulk Insert to 10000000.
The DateAndTime field will record the timestamp from the data source. If tags being logged from an OPC server and the time delivered is different than the local CPU time this can be overridden to use the local CPU clock at the data source of the Tag by setting the property Use TimeStamp from OPC Servers under Configure-Options-OPC to false.
To view the timestamp of any tag go to Configure-Tags and select the tag or parent group and select Add to Watch. View the Watch Window article for an example of use.
Different Time Zones
It is not possible to log remote tag values from a different time zone using Continuous or Continuous Narrow with the local time. In this configuration data must be logged with UTC time. To enable UTC time enable the property Convert Timestamps to UTC under the Common tab.
Another option is to set all tag values to UTC at the data source engine with the option Use UTC Timestamp under Configure-Options-Time.
DateAndTime Field Resolution
By default the DateAndTime field defined under the Tags tab is set to High Resolution with 100 nanosecond resolution. When logging to older versions of SQL Server, Oralce, or mySQL and the System Error Cannot find data type DateTime2 is reported uncheck the property High Precision under the Tags tab of the logging group.
CSV File with Excel
When logging to a CSV file store and forward will be enabled when Excel opens the CSV file currently logged to. Excel locks files for exclusive use when it has a file open. There will be no data loss during this time and all data will be logged when Excel closes the file.