Edit acquisition information for a tag

The Acquisition tab contains basically the same configuration information for analog, discrete, and string tags. However, the tabs for string and discrete tags do not include the Raw Type group or Scaling group.

For information on data acquisition, see Configure data acquisition.

If you change the configuration, then the changes are applied only to data with timestamps that are equal to or greater than the timestamp of the configuration change.

To edit acquisition information for a tag

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

2. Expand Configuration Editor, expand System Configuration, and then expand Tag Configuration.

3. Select the type of tag for which you want to edit the acquisition properties.

4. In the details pane, double-click the tag to edit. The Properties dialog displays.

   

5. Select the Acquisition tab.

6. In the Acquisition Type list, select the method by which the tag's value is acquired. If the tag value is acquired from an I/O Server, specify the name of the I/O Server, topic, and item.

7. In the I/O Server list, select the application name of the I/O Server. This name is usually the same as the executable file name. The list includes all I/O Servers defined in the system.

8. In the Topic Name list, select the name of the topic. The list includes all topics defined for the selected I/O Server.

9. In the Item Name box, type the address string of the tag.

10. If you are editing a discrete or string tag, click OK. Otherwise, continue with the next step.

11. In the Raw Type group, select the numeric type that matches the raw value as it is acquired.

    • Integer
      Integer value. If you select this option, a list appears in which you can select the integer size, in bits, and whether it is signed or unsigned.

    • Float
      IEEE single-precision floating (decimal) point value, which supports approximately 7 decimal places. All floating point calculations are performed with 64-bit resolution, but the result is stored as a 32-bit number. Note that IDAS/SuiteLink can only send single-precision values.

    • Double
      IEEE double-precision floating (decimal) point value, which supports approximately 13 decimal places. The data is stored with 64-bit resolution. Note that if the source can only send single-precision values, storing as a double with a higher resolution consumes space with no added benefit.

      Note: For Float and Double types, some values may vary slightly from those shown in the source. See About floating-point values for more information.

12. In the Scaling group, select the type of algorithm used to scale raw values to engineering units. For linear scaling, the result is calculated using linear interpolation between the end points. The following options are required for linear scaling.

    • Min Raw
      The minimum value of the raw acquired value.

    • Max Raw
      The maximum value of the raw acquired value.

13. Click OK.