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Question: WinCC OA is not allowing to achieve values with timestamps older than current system time (over MQTT).
We have a tag that takes values from a MQTT Broker (OA is the subscriber). When the communication breaks between OA and broker, the broker buffers the published data (for the topic that we've subscribed to in OA). Upon reconnection the broker sends the data (along with the real time data simultaneously), but the data with timestamps older than current system time is marked as invalid and isn't even logged at the timestamp it was supposed to.
Responses (1)
WinCC OA can handle data with a time stamp which is older than the current system time.
What you have to take into account is that for a single DP element data must be written in correct chronological order. If a value is written with a time stamp older than the one for the last value change, the value is accepted (last time +1 ms) and the "time invalid" status bit is set.
In your case the problem will be that newer values are send first by the broker and afterwards older values are transmitted.
Possibly you can change the behaviour of the broker to send data in correct timely order.
Best Regards
Leopold Knipp
Senior Support Specialist