Timestamp problem

[cpollak]

Hello!


I have a problem of which I am not entirely sure if it is caused by WinCC OA or my hardware.

I am measuring data with power monitoring devices (Sentron PAC3200 and PAC4200) as well as pressure- and flow-sensors (via a S7-1200 PLC). In WinCC OA I am using MODBUS and S7 drivers and for all corresponding datapoints, polling is set to 100 ms.

However, for most datapoints I only get a non-consistent resolution of around 200 ms and the timestamps do not have the same starting point. Here you see a list of example-data (timestamps in ms) retrieved from the database.

As you can see, this behavior even occurs for values measured with the same hardware.

Do you know this issue? Does it have something to do with my WinCC OA setup? The larger timestep-jumps might have to do with my low-level-comparison settings (ON for all datapoints), is that correct?

I would like to achieve having the same timestamp for each measured value.


Thank you in advance for any tipp!

[cpollak]

Status update: With disabling the low-level comparison option I achieved an average time of around 100 ms between two measured values. However, I still have occasional outliers (values ranging from 10 to several 100 ms). Everything below 100 ms resolution is no problem. Everything above, however, must be avoided.

Is there anything I can do about that?