Edit storage rules for a topic

To edit storage rules for a topic

1. In the Operations Control Management Console tree, expand a server group and then expand a server.

2. Expand Configuration Editor, expand System Configuration, and then expand Data Acquisition.

3. Expand the IDAS and then the I/O Server that contains the topic to edit.

4. Right-click the topic to edit, and then click Properties. The Properties dialog box appears.

5. Click the Set Storage Rules tab.

   

6. In the Set Time Stamp of list, select the whether the timestamp of the data source or the Historian server (specifically, HCAL) should be used. Choosing the server option is useful if the source-supplied timestamp is unreliable. Note that the Historian handles incoming data that has a timestamps in the future.

   Note: If a fast-changing tag is configured to use server timestamping, the packet of data that is sent to the storage subsystem may contain multiple data values with the same timestamp, which may affect data calculations, such as for swinging door storage.

7. In the Storage Type group, configure the storage rule for all the tags associated with the topic:

   • Unchanged -- Use this if no storage rule is applied at the topic level.

   • Delta -- Use this if tag values are stored only if they have changed.

   • Cyclic -- Use this if tag values are stored according to a fixed rate, which you can select from the Storage Rate list.

   • None -- Use this if tag values from this topic are stored are not stored into history.

   • Forced -- Use this if all values received from this topic are stored.

8. In the Deadband group, configure the deadband. Options in this group are only available if delta storage is selected in the Storage Type group. For the deadband type you select, configure the appropriate options.

   • Unchanged -- Use this if no storage rule is applied at the topic level.

   • Time and/or Value -- A time deadband is the minimum time, in milliseconds, between stored values for a single tag. Any value changes that occur within the time deadband are not stored. The time deadband applies to delta storage only. A time deadband of 0 indicates that the system will store the value of the tag each time it changes.

     A value deadband is the percentage of the difference between the minimum and maximum engineering units for the tag. Any data values that change less than the specified deadband are not stored. The value deadband applies to delta storage only. A value of 0 indicates that a value deadband will not be applied.

   • Swinging Door -- A swinging door deadband is the percentage of deviation in the full-scale value range for an analog tag. The swinging door (rate) deadband applies to delta storage only. Time and/or value deadbands can be used in addition to the swinging door deadband. Any value greater than 0 can be used for the deadband. A value of 0 indicates that a swinging door deadband will not be applied.

9. If you specify a Delta storage type, mark the corresponding check box and specify the parameters for the deadband type you selected:

   • Apply Time Deadband -- Specify time in milliseconds.

   • Apply Value Deadband -- Specify value as a percentage of the engineering unit for that tag.

   • Apply Rate Deadband -- Specify rate as a percentage.

10. In the Set Acquisition box, specify whether to turn data acquisition from the topic on or off. The Unchanged option allows you to leave current acquisition settings unchanged, which is useful if you have a mix of acquired and not acquired tags on the topic and do not want to go through all of them.

11. Click OK.