Locks prevent users from changing the parameters and parameter fields assigned to the lock. By themselves, locks have no function. They become functional (that is, prevent user changes) only when they are assigned to specific parameters or parameter fields. This lock assignment is done using the DeltaV Explorer application.
You can change the name of any of the available locks and add a description to the lock for further identification in User Manager.
Keys provide permission to individual users or whole groups of users to access locked parameters or parameter fields. Keys are granted in the DeltaV User Manager under the Keys tab of the Group Properties and User Properties dialogs.
Locks are assigned to specific module parameters and parameter fields in the DeltaV Explorer. Security is accessed in the Explorer hierarchy under . After selecting either Parameter Security or Field Security, right-click, and then click Properties to modify the security properties.
Locks are assigned to parameter names rather than to specific instances of parameters. For example, a lock on HI_LIM applies to all instances of parameters named HI_LIM. To lock a specific instance of a parameter, you must create a unique name for that parameter, such as HI_LIM1.
Locks and keys assigned at the field level override those on the parameter itself. This means that specific parameter fields can be open to a large number of users while the parameter as a whole is generally restricted.
The system handles user write requests in the following way. A user makes a write request to a specific parameter field. The system checks to see if there is a lock on the parameter field. If there is not, the system checks to see if there is a lock on the parameter itself. If there is no lock on the parameter, the user may write to the parameter. If there is a lock at the field level, users who have a key may write to the field, even if they do not have a key to the parameter itself.