DB_ENABLE_MSEC

About this task

For Database Logger System or Project
Purpose To create a separate column in which the CIMPLICITY Data Logger will store the sub-second portion of the timestamps to the nearest millisecond. This capability can be important when a database is not capable of storing time values with a timestamp accuracy of 1/1000 of a second, which is the accuracy that CIMPLICITY Data Logger achieves. In fact, most databases can only handle storing time values to the nearest second. Therefore when timestamps are inserted into the database, their values are either truncated or rounded, by the database, to a value that complies with the database's storage capabilities. You can create DB_ENABLE_MSEC in either the Project or the System folder. The result is as follows:
Folder Global Parameter will be used by:
System Millisecond Logging compatible clients whom are started outside the scope of the project environment and copied into all new CIMPLICITY projects that you create (e.g. Starting a CimView screen outside of a project).
Project Only the project's logging processes and Millisecond Logging compatible clients started within the context of the project environment.
Value Values include:
Y Creates a separate column.
N Does not create a separate column.
Default Value msec is the default name of a field that CIMPLICITY creates in the database. Note: CIMPLICITY names the field msec. To change this name, use the global parameter DB_MSEC_FIELD.
Important:

Procedure

  1. If you want to enable DB_ENABLE_MSEC, create or enable the parameter before you create any tables in the database.

    CIMPLICITY creates the field as part of a table's primary key when it creates the table. CIMPLICITY creates tables when you start your project for the first time or reconcile a table through the Database Logger Configuration program. Therefore, you will have to drop any table that exists before you create or enable DB_ENABLE_MSEC so CIMPLICITY can recreate them with the new field.

  2. If you want to disable DB_ENABLE_MSEC, drop existing tables and let CIMPLICITY recreate them without the parameter enabled.

    Failure to do this will cause logging of data to malfunction because the database will reject the inserted data due to constraint violations.

  3. If you are logging data from multiple projects to the same database then all projects must have the feature identically configured.
  4. If you are using DB_ENABLE_MSEC on more than one computer, including servers and viewers, add DB_ENABLE_MSEC on each.
  5. Only Point Logging, Alarm Logging and Trending clients fully support this feature.

    To alter the name that CIMPLICITY uses to refer to or create the field in the database, create another global parameter, name it DB_MSEC_FIELD, and provide the appropriate string value for the field name.