string atomic write issue

Hi

I'm using a flexy 205  for historical logging our Mobile gully system.  This is sending & receiving data from 3 Siemens PLC's (S1515 and 2 times S1513) and I have problems with string values:

Sometimes he is sending 2 times the same value, somethimes it seems that the string is not completely readed.
I have this problem with all strings. In the PLC program I empty the string first, I have used a positive trigger already.

Any other suggestions?

Thanks

Thomas

Hi Thomas,

How do you send these values ? Can you give me more details ?
Do you record them using the historical logging ?

Hi Thomas,

How do you send these values ? Can you give me more details ?
Do you record them using the historical logging ?

Hi Simon,

Thomas is responsible for the PLC code, while I created the BASIC code to upload all changing tags values as JSON via MQTT to Azure. See attachment for details.
We are having these issues at the start of our project, but as the project is growing it is very hard to keep on writing extra 'cleanup' code from the variables. So we rather want to deepdive in the root cause of this. We most of the times see that strings are just missing one or more characters and sometimes the final complete string is then sent in the next JSON that is created.

Please let us know if you need more/other information.

Thanks in advance.

Hi,

My guess is that the reading of the string can happen while the string is updated by the PLC.
We could create a trace of the traffic of the Ewon LAN to check that. (I have a tool for that that I can give you).

All the options I see will involve some more script unfortunately.
You can perhaps try to isolate the string values in an IOServer topic and set a higher polling rate for this topic ? I guess these string do not change at a high frequency...