A resource can only be manipulated by its owner. If an operator does not own a resource he wants to control, he must first acquire ownership of the resource.
However, an operator can only acquire a resource if the resource has been acquired by less than the maximum number of owners defined for it. The number of owners a resource is allowed to have is configured in DeltaV Explorer. For additional information on defining resource ownership, refer to the Configuring Equipment topic.
Caution Setting Maximum Owners on unit phases and phase logic modules to any value greater than 1 is strongly discouraged as a phase cannot be successfully run by multiple owners at the same time.
Maximum Owners on a unit allows different phases to own the same unit and run on that unit simultaneously.
As an example of resource ownership, suppose an operator is running Batch-A and wants to close a particular valve manually during the batch process. However, Batch-B is running simultaneously, and the valve in question is being used by Batch-B, too. The valve is defined as being owned by Batch-B, so the operator running Batch-A is unable to control the valve until he establishes ownership of the valve.
By accessing the Arbitration Screen, the operator can request ownership of the valve, which would then allow him to operate the valve manually. Several factors are involved in determining whether to grant ownership rights to the operator. These include the following:
Number of owners - If the number of owners already exceeds the maximum number configured in the DeltaV Explorer, ownership cannot be given to the operator.
Request priority - If there is more than one requester for this valve and the other requesters are listed higher in the Needed By list, ownership is given first to the requesters higher on the list. However, by accessing the Arbitration screen, operators can reposition their request in the priority list.
The operator can be granted ownership of the valve when the:
At that point, the operator is free to manipulate the valve manually.