Siemens SIMATIC ET 200AL, System Manual

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OPC UA communication
9.3 Using the S7-1500 as an OPC UA server
Communication
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Function Manual, 05/2021, A5E03735815-AJ
9.3.7.7 Summarizing diagnostics
To prevent the diagnostics buffer being "swamped" by large numbers of identical OPC UA
diagnostics, as of STEP 7 V16 service pack 1, you can set parameters so that these diagnostics
are entered in the diagnostics buffer as group alarm. Per interval (monitoring time), the CPU
then only generates one group alarm per OPC UA diagnostics.
The following sections describe which diagnostics the CPU groups together and how the
process runs with a high message volume.
Requirement
The "Summarize diagnostics in case of high message volume" option is activated in the OPC
UA properties of the CPU (OPC UA > Server > Diagnostics, "Summarize diagnostics" area).
Example
An OPC UA client repeatedly "overloads" an S7-1500 CPU as OPC UA server with a sampling
rate that the server cannot handle (overload).
The "Summarize diagnostics in case of high message volume" setting is activated.
A message appears in the diagnostics buffer for this diagnostic option. It states that the
sampling rate cannot be reached; followed by the number of these events within the
configured interval.
OPC UA diagnostics that can be summarized
The diagnostics listed below each form their own groups (type). Diagnostic events from the
same group are combined using the setting "Summarize diagnostics in case of high message
volume":
•
Incorrect use of an OPC UA service
• OPC UA Service error
• Subscription status has changed
• Sampling rate could not be achieved (subscriptions, overload)
• OPC UA security check failed
• Configuration limit of the OPC UA server violated