Service Level implementation between OPC UA Server and Client | OPC UA Standard | Forum

Avatar
Search
Forum Scope


Match



Forum Options



Minimum search word length is 3 characters - maximum search word length is 84 characters
Lost password?
sp_Feed sp_PrintTopic sp_TopicIcon
Service Level implementation between OPC UA Server and Client
Avatar
Benedetto Bozano
New Member
Members
Forum Posts: 2
Member Since:
09/23/2014
sp_UserOfflineSmall Offline
1
11/13/2020 - 10:06
sp_Permalink sp_Print

Hello Everyone!

I'm facing an issue with a customer who has an OPC UA Server not in a redundant configuration which exposes ServiceLevel = 0.

The OPC UA Client we are using is not able to establish a connection to the server because it detects ServiceLevel = 0 and assumes the server is in maintenance mode.

The customer and the OPC UA Server provider are arguing that ServiceLevel should only be considered by the Client if the Server is in a redundant configuration, which is not the case.

My interpretation, which is based on the sentence below from chapter 6.6.2.4.2 ServiceLevel of the OPC UA specification, part 4, is that any server should properly set the ServiceLevel according to the specification, even when in standalone mode:

All Servers, regardless of Redundant Server Set membership, shall adhere to the sub-ranges defined in Table 109.

I hope that the question is clear and that someone can help me clarify this point!

Thanks in advance to anyone who can support!

Benedetto

Avatar
Randy Armstrong
Admin
Forum Posts: 495
Member Since:
05/30/2017
sp_UserOfflineSmall Offline
2
11/13/2020 - 10:40
sp_Permalink sp_Print sp_EditHistory

The spec reference is here:
https://reference.opcfoundatio.....#6.6.2.4.2
https://reference.opcfoundatio.....rt5/6.3.1/

The statement is unambiguous and consistent with Part 5:

All Servers, regardless of Redundant Server Set membership, shall adhere to the sub-ranges defined in Table 109.

So yes, your interpretation is correct. The server is needs to set the value to 255 even if it is not configured for redundancy.

I would go one step further: if the specification wording was ambiguous then I would raise the issue with the UA WG and ask them make sure that there is no doubt that your interpretation is correct.

After reviewing the text, I do not see it as ambiguous.

Avatar
Benedetto Bozano
New Member
Members
Forum Posts: 2
Member Since:
09/23/2014
sp_UserOfflineSmall Offline
3
11/13/2020 - 10:52
sp_Permalink sp_Print

Thank you Randy for your very fast answer! Hopefully it will help me in the discussions with the customer. I'm also going to follow your suggestion and check with UA WG.

Thanks,

Benedetto

Forum Timezone: America/Phoenix
Most Users Ever Online: 202
Currently Online:
Guest(s) 7
Currently Browsing this Page:
1 Guest(s)
Top Posters:
Forum Stats:
Groups: 2
Forums: 9
Topics: 771
Posts: 2275