Configure Replicated Namespace
Configuring a replicated namespace consist mainly of determining how the generation of items will be done. Variables (that extends BaseDataVariableType) in the namespace are nodes that holds some kind of data that varies, i.e. the value of a temperature sensor. To keep the aggregating server updated with the latest values, the values are updated from the remote server by subscription. Internally in the aggregating server, the variables values are stored in Apis Hive OPC items. By using items, the subscribed to values will also be available from an OPC DA client.
For a replicated namespace, one needs to determine which variables to create items for, and how to generate the item names.
The configuration properties for a replicated namespace, are the following:
Misc:
| Property Name | Explanation |
|---|---|
| Exposed URI | The exposed namespace which the remote uri is mapped to. This is the namespace uri that clients that connect to the aggregating server will see. This may or may not be the same as the Source URI. |
| Item generation | Specifies when items used to hold variable-values should be generated for the replicated namespace. • If no types in namespace: Generate items if there are no Types in the namespace (only instances) • Always: Generate items for all variables (this will include instance declarations) • Never: Do not create items • Datavariables that are not instance declarations: Generate items for all variables other than instance declarations. |
| Namespace store | Specifies the database file used to hold the local replicated namespace representing the remote URI. |
| Source URI | The remote source namespace to replicate |
Item naming:
| Property Name | Explanation |
|---|---|
| Path element | Specifies which attributes to use when generating names for items to hold datavariable-values. • Default • NodeId: use the node id only • Browsename: use the browsename only • Browsename and NodeId: use the browsename and the node id • Displayname: use the displayname only • Displayname and NodeId: use the displayname and the node id |
| Path rule | Specifies how far up the hierarchy to go when generating names for items to hold datavariable-values. |
| Name hierarchy cache depth | How many levels, counted from the objects folder, to cache names during itemname generation. Specify 0 to cache everything. May use a lot of memory on large systems. |
| Path separator | Specifies the separator character to use between parent-child relationships when generating names for items to hold datavariable-values. |
Naming root:
| Property Name | Explanation |
|---|---|
| Fail policy | Specifies how to handle the situation when a naming root is not detected along the parent-child hierarchy. • Fail: Abort crawl with an error message • Stop at first object node: Include the path elements up to, and including, the first parent that is an object • Stop at objects folder: Include the path elements up to the Objects folder |
| Include subtypes | Specifies whether instances of subtypes of the naming root type are accepted as naming root. |
| Node Id | Specifies the node id of the naming root type node |