Owning Palette: Alarms and Conditions VIs

Requires: OPC UA Toolkit

Adds a notifier to a parent folder. A notifier is an object that you can subscribe to get events from the associated condition nodes. To establish an event hierarchy, you can add a condition node and a source node as child nodes to a notifier.

For some condition node types, you need to add an extra node:

  • If the condition node is a deviation alarm, you need to add a setpoint node.
  • If the condition node is an off-normal alarm, you need to add a normal state node.

Example

historical access specifies whether the parent folder supports historical access and the size of the history event queue.
enable specifies whether the analog item supports historical access. The default is FALSE, which specifies that this item does not support historical access.
queue size specifies the size of the queue of history events. The default is 1000. A history event queue can store one history event only. You can add a history event queue only to a notifier. NI recommends adding the condition node and the source node to the notifier so that they share one history event.
OPC UA server refnum in specifies the reference data value of the OPC UA server.
parent folder node ID specifies the ID of the parent folder. The format of the node ID is ns=<namespace index>;<identifier type>=<identifier>. If the parent folder does not exist, this VI creates a folder at the root level. A node ID contains the following components:
  • namespace index is a base 10 number that indicates the namespace of the node ID.
    Note If namespace index is 0, the format of the node ID can be <identifier type>=<identifier>. The namespace index for a node that you created with the OPC UA Toolkit is 2.
  • identifier type represents the type of the identifier and has the following values:
    ValueIdentifier Type
    iNumeric
    sString
    gGUID
    bOpaque
  • identifier is a string value that represents the name of the identifier.
The format of the node ID can also be ns=<namespace index>;<identifier type>=<identifier>@<index>:<index>. For example, ns=2;s=Folder.Array@1:2. This format only applies to the array data type and allows you to read a single element or a range of elements of an array. You cannot use @ in a node name. For backwards compatibility, parent folder node ID also accepts node paths as input for OPC UA servers only. You can regard the node path as the string type identifier of the node ID. For example, a node path can be Device.folder.item.
notifier name specifies the name of the notifier.
error in describes error conditions that occur before this node runs. This input provides standard error in functionality.
description specifies additional information of the notifier.
OPC UA server refnum out returns the reference data value of the OPC UA server.
notifier node ID returns the ID of the notifier.
OPC UA notifier refnum out returns the reference data value of the OPC UA notifier.
error out contains error information. This output provides standard error out functionality.

Example

Refer to the OPC UA Demo.lvproj in the labview\examples\Data Communication\OPCUA directory for an example of using the Add Notifier VI.