Real time Trend chart lines are 50 seconds late

Most recent data displayed on our Real Time Trends are 50 seconds old.
Is this latency to be expected?

I haven’t seen it quite that bad before…

Is your data being stored/retrieved using the historian?
Have you checked the delay between the client and gateway, and between the gateway and database?

Synchronize your Clients and Gateway and Database clocks.

This is Easy Chart displaying R/T data.
Watching PLC and HMI interaction: Latency between PLC / HMI is ~ 1+ seconds.

Multiple Clients, including my (remote) development computer show the same symptom.

Not sure what you mean by synchronizing Gateway and Client clocks?
Do you mean at the operating system level?
Does a difference in time setting between computers really affect display of R/T chart?

Thank you for the response,

Forgot to state:
The R/T display shows 50 seconds of blank space between right edge and first trace. Scaling the duration changes the width of the gap but the actual delay remains the same,

Yes.

And yes.

The OS clock at the client is used to create the date bounds for the chart. If the clock is wrong, it won’t match the data recorded.

Since you have the problem on all your clients, the gateway’s clock is probably the culprit.

1 Like

Good call there, pturmel!
Gateway computer time was set, but sync not enabled.
Somehow, somewhere, gateway clock was off by 50 seconds from the rest of the world.
Changed Gateway PC time and all is well.
I don’t understand why or how. Seems to me the gateway records, then delivers the data, so any time discrepancy should carry through. But it does not …

Thank you
regards
GF