Pending File

On a Global network, most remote commands that are stalled for any reason at a location are placed in the transaction database at that location, for later processing.

A small number of commands that cannot be carried out at once, known as ‘kernel’ commands, are instead stored in a location’s pending file for later processing. There are various situations where kernel commands may be added to a pending file. For example:

• Too many commands have been issued in quick succession.

• A communication link is down.

The kernel commands are:

• ISOLATION TRUE/FALSE

• LOCK/UNLOCK

• PREVOWNER HUB

Also, for a Satellite’s transaction database:

• ALLOCATE (PRIMARY)

• CHANGE PRIMARY

  All other commands use the transaction database to achieve a similar effect (see next chapter).

Once a pending file has been created at a location, it will continue to exist. When the kernel commands stored in it have been executed, they will be deleted from the file. The user can tell if there are any outstanding commands by the size of the file: if it is empty, it will be zero size. The contents of the pending file can be read by using a utility available from AVEVA.

The pending file is named pending, and it will be saved in the project directory. It can be read using the glbpend.exe utility provided in the Global install folder.

For example, if the pending file is

C:\Users\Public\Documents\AVEVA\Projects\AvevaPlantSample\aps000\pending

The command to read it is:

C:\ProgramFiles(x86)\AVEVA\GlobalServer3.3\glbpend.exeC:\Users\Public\Documents\AVEVA\Projects\AvevaPlantSample\aps000\pending

The pending commands can be read from the output.