Add Condition VI
- Updated2025-09-30
- 28 minute(s) read
Owning Palette: Alarms and Conditions VIs
Requires: OPC UA Toolkit
Adds a condition node to the notifier.
You must manually select the polymorphic instance to use.
Add Dialog Condition
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OPC UA server refnum in specifies the reference data value of the OPC UA server. | ||||||||||||||||||
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notifier node ID specifies the ID of the notifier. A notifier is an object that you can subscribe to get events from the associated condition nodes. The format of the node ID is ns=<namespace index>;<identifier type>=<identifier>. A node ID contains the following components:
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property specifies the properties of the condition node.
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error in describes error conditions that occur before this node runs. This input provides standard error in functionality. | ||||||||||||||||||
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OPC UA server refnum out returns the reference data value of the OPC UA server. | ||||||||||||||||||
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condition node ID returns the ID of the condition node. | ||||||||||||||||||
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OPC UA dialog condition refnum out returns the reference to the dialog condition. The OPC UA server uses the dialog condition to request user input. | ||||||||||||||||||
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error out contains error information. This output provides standard error out functionality. |
Add Off-Normal Alarm
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OPC UA server refnum in specifies the reference data value of the OPC UA server. | ||||||||||||||||||
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notifier node ID specifies the ID of the notifier. A notifier is an object that you can subscribe to get events from the associated condition nodes. The format of the node ID is ns=<namespace index>;<identifier type>=<identifier>. A node ID contains the following components:
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property specifies the properties of the condition node.
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error in describes error conditions that occur before this node runs. This input provides standard error in functionality. | ||||||||||||||||||
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OPC UA server refnum out returns the reference data value of the OPC UA server. | ||||||||||||||||||
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condition node ID returns the ID of the condition node. | ||||||||||||||||||
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OPC UA off normal alarm refnum out returns the reference to an off-normal alarm condition node. An off-normal alarm condition represents an abnormal condition. | ||||||||||||||||||
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error out contains error information. This output provides standard error out functionality. |
Add Exclusive Level Alarm
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OPC UA server refnum in specifies the reference data value of the OPC UA server. | ||||||||||||||||||||||||||
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notifier node ID specifies the ID of the notifier. A notifier is an object that you can subscribe to get events from the associated condition nodes. The format of the node ID is ns=<namespace index>;<identifier type>=<identifier>. A node ID contains the following components:
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property specifies the property of the condition instance.
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error in describes error conditions that occur before this node runs. This input provides standard error in functionality. | ||||||||||||||||||||||||||
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OPC UA server refnum out returns the reference data value of the OPC UA server. | ||||||||||||||||||||||||||
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condition node ID returns the ID of the condition node. | ||||||||||||||||||||||||||
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OPC UA limit alarm refnum out returns the reference to the OPC UA limit alarm condition. | ||||||||||||||||||||||||||
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error out contains error information. This output provides standard error out functionality. |
Add Exclusive Deviation Alarm
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OPC UA server refnum in specifies the reference data value of the OPC UA server. | ||||||||||||||||||||||||||||
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notifier node ID specifies the ID of the notifier. A notifier is an object that you can subscribe to get events from the associated condition nodes. The format of the node ID is ns=<namespace index>;<identifier type>=<identifier>. A node ID contains the following components:
|
||||||||||||||||||||||||||||
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property specifies the property of the condition instance.
| ||||||||||||||||||||||||||||
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error in describes error conditions that occur before this node runs. This input provides standard error in functionality. | ||||||||||||||||||||||||||||
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OPC UA server refnum out returns the reference data value of the OPC UA server. | ||||||||||||||||||||||||||||
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condition node ID returns the ID of the condition node. | ||||||||||||||||||||||||||||
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OPC UA limit alarm refnum out returns the reference to the OPC UA limit alarm condition. | ||||||||||||||||||||||||||||
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error out contains error information. This output provides standard error out functionality. |
Add Exclusive Rate of Change Alarm
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OPC UA server refnum in specifies the reference data value of the OPC UA server. | ||||||||||||||||||||||||||
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notifier node ID specifies the ID of the notifier. A notifier is an object that you can subscribe to get events from the associated condition nodes. The format of the node ID is ns=<namespace index>;<identifier type>=<identifier>. A node ID contains the following components:
|
||||||||||||||||||||||||||
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property specifies the property of the condition instance.
| ||||||||||||||||||||||||||
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error in describes error conditions that occur before this node runs. This input provides standard error in functionality. | ||||||||||||||||||||||||||
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OPC UA server refnum out returns the reference data value of the OPC UA server. | ||||||||||||||||||||||||||
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condition node ID returns the ID of the condition node. | ||||||||||||||||||||||||||
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OPC UA limit alarm refnum out returns the reference to the OPC UA limit alarm condition. | ||||||||||||||||||||||||||
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error out contains error information. This output provides standard error out functionality. |
Add Nonexclusive Level Alarm
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OPC UA server refnum in specifies the reference data value of the OPC UA server. | ||||||||||||||||||||||||||
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notifier node ID specifies the ID of the notifier. A notifier is an object that you can subscribe to get events from the associated condition nodes. The format of the node ID is ns=<namespace index>;<identifier type>=<identifier>. A node ID contains the following components:
|
||||||||||||||||||||||||||
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property specifies the property of the condition instance.
| ||||||||||||||||||||||||||
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error in describes error conditions that occur before this node runs. This input provides standard error in functionality. | ||||||||||||||||||||||||||
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OPC UA server refnum out returns the reference data value of the OPC UA server. | ||||||||||||||||||||||||||
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condition node ID returns the ID of the condition node. | ||||||||||||||||||||||||||
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OPC UA limit alarm refnum out returns the reference to the OPC UA limit alarm condition. | ||||||||||||||||||||||||||
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error out contains error information. This output provides standard error out functionality. |
Add Nonexclusive Deviation Alarm
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OPC UA server refnum in specifies the reference data value of the OPC UA server. | ||||||||||||||||||||||||||||
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notifier node ID specifies the ID of the notifier. A notifier is an object that you can subscribe to get events from the associated condition nodes. The format of the node ID is ns=<namespace index>;<identifier type>=<identifier>. A node ID contains the following components:
|
||||||||||||||||||||||||||||
![]() |
property specifies the property of the condition instance.
| ||||||||||||||||||||||||||||
![]() |
error in describes error conditions that occur before this node runs. This input provides standard error in functionality. | ||||||||||||||||||||||||||||
![]() |
OPC UA server refnum out returns the reference data value of the OPC UA server. | ||||||||||||||||||||||||||||
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condition node ID returns the ID of the condition node. | ||||||||||||||||||||||||||||
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OPC UA limit alarm refnum out returns the reference to the OPC UA limit alarm condition. | ||||||||||||||||||||||||||||
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error out contains error information. This output provides standard error out functionality. |
Add Nonexclusive Rate of Change Alarm
![]() |
OPC UA server refnum in specifies the reference data value of the OPC UA server. | ||||||||||||||||||||||||||
![]() |
notifier node ID specifies the ID of the notifier. A notifier is an object that you can subscribe to get events from the associated condition nodes. The format of the node ID is ns=<namespace index>;<identifier type>=<identifier>. A node ID contains the following components:
|
||||||||||||||||||||||||||
![]() |
property specifies the property of the condition instance.
| ||||||||||||||||||||||||||
![]() |
error in describes error conditions that occur before this node runs. This input provides standard error in functionality. | ||||||||||||||||||||||||||
![]() |
OPC UA server refnum out returns the reference data value of the OPC UA server. | ||||||||||||||||||||||||||
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condition node ID returns the ID of the condition node. | ||||||||||||||||||||||||||
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OPC UA limit alarm refnum out returns the reference to the OPC UA limit alarm condition. | ||||||||||||||||||||||||||
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error out contains error information. This output provides standard error out functionality. |
Add Condition Details
The dialog is a condition that an OPC UA server uses to request user input.
Alarms are specializations of acknowledgeable conditions that add the concepts of an active state, a shelving state, and a suppressed state to a condition. This VI supports the following alarm types:
- Off-normal alarmSpecifies a condition that is not normal.
- Limit alarmSpecifies limits that can generate an alarm when a value equals or exceeds the limit. There are four alarm limits: high high limit, high limit, low limit, and low low limit. This VI supports the following limit alarm types:
- Exclusive alarmContains multiple mutually exclusive limits. For an exclusive alarm, multiple states can be active at the same time.
- Nonexclusive alarmContains multiple nonexclusive limits. For a nonexclusive alarm, only one state can be active at a specific time.
- Level alarmReports when a limit is exceeded.
- Deviation alarmReports an excess deviation between a desired setpoint level of a value and an actual measurement of that value.
- Rate of change alarmReports an unusual change or lack of change in a measured value related to the speed at which the value has changed.
The condition type affects the available data types of the source node and the normal state node:
- For the dialog condition type, the data type of the source node must be Boolean.
- For the off-normal alarm condition type, the data type of the source node and the normal state node must be scalar and they must have the same data type.
- For the deviation alarm condition type and level alarm condition type, the data type of the source node must be Double.
- For the rate of change alarm condition type, the source node must be analog data and the data type must be scalar.
Example
Refer to the OPC UA Demo.lvproj in the labview\examples\Data Communication\OPCUA directory for an example of using the Add Condition VI.








