OPC UA
- Last UpdatedJun 25, 2026
- 3 minute read
Configure OPC UA client settings to define how the adapter connects to an OPC UA server and exchanges data during runtime.
These settings typically specify the server endpoint, security policy, message security mode, authentication method, certificate handling, session behavior, and connection retry options.
Review these settings carefully to ensure that the adapter can establish a trusted, secure, and reliable connection to the OPC UA server before data collection begins.
Client settings parameters
The following table lists parameters available for client settings:
|
Parameter |
Description |
|---|---|
|
Max Browse References To Return |
Maximum number of references returned from browse call. |
|
Browse Block Size |
Maximum number of nodes to browse in one call. |
|
Child Event Property Level |
Maximum level of child event properties to discover in event type discoveries. Note: This parameter only applies to the Events discovery operation. The adapter's data selection can be manually configured with child event properties up to any level. |
|
Reconnect Delay |
Delay between reconnection attempts. Does not apply to the initial connection, only reconnections. |
|
Recreate Subscription Delay |
Delay between successful reconnection and subsequent subscription recreation. |
|
Read Block Size |
Maximum number of variables to read in one call. |
|
Session Request Timeout |
Default request timeout. |
|
Connection Timeout |
Connection timeout. |
|
Read Timeout |
Read operation timeout. |
|
Session Allow Insecure Credentials |
When the checkbox is selected, credentials can be communicated over unencrypted channel. |
|
Session Max Operations Per Request |
Default maximum operation per request. |
|
Browse Timeout |
Browse operation timeout. |
|
Max Monitored Items Per Call |
Maximum number of monitored items that can be added to subscription in one call. |
|
Max Notifications Per Publish |
Maximum notification messages in one publish message. |
|
Publishing Interval |
Publishing interval of the subscription. |
|
Create Monitored Items Timeout |
Create monitored items timeout. |
|
Monitored Item Data Change Trigger |
Determines on what conditions a subscription sends new values to the adapter. Available values: Status, StatusValue, StatusValueTimestamp |
|
Sampling Interval |
Sampling interval for monitored items created by the adapter. |
|
Monitored Item Queue Size |
Controls the size of the per-item publishing queue on the OPC UA server. This value must be set large enough to hold the amount of samples expected within a publishing interval. For Hot server failover, set this large enough to buffer enough samples during a failover event so that data will not be lost. |
|
Event Type Monitored Item Queue Size |
Controls the size of the per-item publishing queue for event monitored items on the OPC UA server. This value must be set large enough to hold the number of samples expected within a publishing interval. |
|
Max Internal Queue Size |
Maximum number of items that can be in the adapter internal queue. |
|
History Read Block Size |
Maximum number of nodes for history to read in one call. |
|
History Read Timeout |
History read operation timeout. |
|
Operation Timeout |
Maximum Timeout for all other operations related timeouts, except session requests. |
|
Minimum Event Severity |
This value determines the minimum number of events sent. If the value is set to 0, all events with a Severity below the value set for the Maximum Event Security will be sent. |
|
Maximum Event Severity |
This value determines the maximum number of events sent. If the value is set to 1000, all events with a Severity above the value set for the minimumEventSecurity will be sent. |
|
Event String Delimiter |
Delimiter for event fields in the egress string. Available values: “|”, “;”,“-”, “,” |
|
Include Event Property Name |
When the checkbox is selected, the event property names are included with values. |