Siemens SIMATIC S7-1500 Function Manual page 240

Possible entries for the service that is causing the error
Depending on the client application used, requests to the server can be triggered differently
from the user's viewpoint, for example, by an online tool with a graphical user interface or by
instructions in a client's program.
With its service-oriented architecture, OPC UA follows a request-response paradigm,
therefore the respective client application converts the requests into the service requests
defined in OPC UA.
The names of these services are defined and grouped according to their use, see also
opcfoundation.org.
In the case of an incorrect use, you can find precisely these names of the services, together
with the corresponding session ID, in the diagnostic buffer as the service that caused the
error.
The services available with OPC UA are listed below.
Discovery Service Set
FindServers
GetEndpoints
Session Service Set
CreateSession
ActivateSession
CloseSession
Cancel
View Service Set
Browse
BrowseNext
TranslateBrowsePathsToNodeIds
RegisterNodes
UnregisterNodes
Attribute Service Set
Write
Read
Method Service Set
Call
Communication
Function Manual, 11/2019, A5E03735815-AH
OPC UA communication
9.3 Using the S7-1500 as an OPC UA server
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