Change step program and alias configuration at run time

You can update the step program or the Alias configuration or both of them at the same time by using the PrgSeqConfig and PrgSeqConfigCmd attributes. The advantage of this is that you can add extra security to this attribute.

To update these attributes:

• Stop the step program execution so that it is either in Stopped, StoppedComplete or StoppedError state.

• Write the step program configuration and/or Alias configuration and/or settings to the PrgSeqConfig attribute. At this point there is no update to the run-time configuration.

  • Tell the Sequencer object to update its run-time configuration. The contents of the PrgSeqConfig attribute are written to the PrgStepProgram and PrgAliasConfig attributes and the run-time configuration is updated. Also the corresponding attributes from the Settings XML section are updated.

To update Sequencer object configuration at run time:

1. Verify that the step program execution is stopped by reading the attribute ExecutionState. If it is not in one of the stopped states, write the value Stop to the enum attribute ExecutionStateCmd.

2. Write the step program configuration and/or Alias configuration as XML string to the PrgSeqConfig attribute.

3. Write the value Update to the enum attribute PrgSeqConfigCmd.

4. Check the attribute PrgSeqConfigStatus for details on the update:

   Value	Description
   Updating	The update is in progress.
   Ready	The update has completed successfully.
   Error	The update encountered a problem. This could be due to a syntax error in the XML data you tried to update the object with.

Additional feedback and results from the update are reflected in the following attributes:

• PrgSeqConfigStatus.Error

• PrgSeqConfigStatus.Desc

• PrgSeqConfigStatus.Code

For a detailed overview of these attributes and their properties, see Sequencer object help.

After the configuration data is successfully updated with the value from PrgSeqConfig, the step program starts running automatically. The attribute PrgSeqConfig is reset to an empty string after a successful update. When you upload configuration data that doesn’t contain all parts of a Sequencer object, for example, if there are no Aliases, the configuration from the file is merged with the currently active run time configuration.