ConditionName identifies the Condition instance that the Event originated from. It can be used together with the SourceName in a user display to distinguish between different Condition instances. If a ConditionSource has only one instance of a ConditionType, and the Server has no instance name, the Server shall supply the name element of the BrowseName of the ConditionType.

Specification says no and provides a default if it does not make sense.

Another question in same area. 

Is it allow to set property ConditionName (in EventType ConditionType) to null or empty according to the OPC UA specifications. 

Thanks

OPC 10000-24, OPC Unified Architecture - Part 24: Scheduler
http://www.opcfoundation.org/UA/Part24/
OPC 10000-25, OPC Unified Architecture - Part 24: Scheduler
http://www.opcfoundation.org/UA/Part24/
OPC 10000-26, OPC Unified Architecture - Part 24: Scheduler
http://www.opcfoundation.org/UA/Part24/

For "OPC 10000-24, OPC Unified Architecture" this is fine, but not for "OPC 10000-25..." and "OPC 10000-26..."

This need to be 

OPC 10000-24, OPC Unified Architecture - Part 24: Scheduler
http://www.opcfoundation.org/UA/Part24/
OPC 10000-25, OPC Unified Architecture - Part 25: ObjectSerialization
http://www.opcfoundation.org/UA/Part25/
OPC 10000-26, OPC Unified Architecture - Part 26: LogObject
http://www.opcfoundation.org/UA/Part26/

Btw: the underlying links for OPC 10000-25 and -26 are correct

And the Bibliography is only in the PDF, not downloaded markdown or browsed spec.

But the Value cannot be Variant.Empty for mandatory properties.

However, the "" rule does not apply if the description of the property makes it clear that "" is not a valid value:

SourceName provides a description of the source of the Event. This could be the string-part of the DisplayName of the Event source using the default locale of the server, if the Event is specific to a Node, or some server-specific notation.

(i.e. "" is not a description)

Clients should be designed defensively to deal with misbehaving Servers but that does not make the server right.

Is it allowed, according to the specifications, to set the value on a mandatory property, in an event, to null. 

For example:

Assuming an event of EventType BaseEventType.

Is it allowed for an OPC UA server to set, for example, property SourceName to null in the event?

If it is, is it the same for any mandatory property in any EventType? 

Should an OPC UA client be able to take that into account?

Thanks

https://mantis.opcfoundation.o.....default=no

https://mantis.opcfoundation.o.....default=no

Section 9.1 General of OPC 10000-3; OPC Unified Architecture Part 3 :Address Space Model; Release 1.05.06; 2025-10-22 starts with "The remainder of 8.61 defines EventTypes." Section 8.61 is about CurrentyUnitType.

See also section 4.1, first paragraph, last sentence: "Standard ReferenceTypes, DataTypes and EventTypes are defined in Clauses 7 to 8.61."

As well section 4.7.2 EventTypes, last paragraph, first sentence: "Standard EventTypes are described in Clause 8.61."

There seem to be a typo, an incorrect or undefined reference.

Thanks and regards

I'm working through the spec, currently OPC 10000-3; OPC Unified Architecture Part 3 :Address Space Model; Release 1.05.06; 2025-10-22.

Annex B, section B 3.4 Object and ObjectType is short with the follwoing text: "Objects and ObjectTypes are shown in Figure B.8."

The description of the figure is given, but the figure itself is missing.

At least the necessary information is shown in figure B.7. Figure B.7 is a bit cluttered and makes it hard to make out specific details.

Best regards

happy to hear that you started working with the CTT to test your product. I assume your problem is something very basic like that the setting has not been stored in the configuration yet, since you haven't clicked on "Apply". You'll find the "Apply" button at the bottom of the settings dialog. Once you applied the configuration change with the endpoint URL the connection should be working fine.

If you are then still facing issues. Please let me know.

Regards,
Alexander Allmendinger

I'm trying to start a project om CTT, but when I add my Server URL i only receive back No endpoints discovered. The same server works well via UAExpert. Any possible causes and solutions?

https://opcfoundation.org/deve.....urce-code/