Siemens S7-1200 Datalogging

[Puddle]

I have some datalogging set up on an S7-1211. Most basic controller, but 1MB of memory should be enough.

A single log is 222 bytes and logs an array of 21 UInt tags, plus a timestamp while logging is active.

However! After 5 logs of a single entry it's telling me that it's out of space. Yes it's a very basic CPU, but according to the diagnostics page on the web server each one of these logs consumes 132.11KB.

Am I missing something here? Even if I used an MMC it would fill up much faster than I thought here.

 

[Mas01]

What's the value of your DataLogCreate.Status - see attachment?

Does its value give an indication of what the problem is?


Also check the memory usage - see attachment.


Does this help?
https://www.plctalk.net/qanda/showthread.php?t=137603

 

[Puddle]

Error 80B3 for insufficient storage, which is right because it was showing load memory at 93.2%.

My concern is that it should be taking 222B, which is the size that the csv file is when downloaded, but when that datalog is deleted it frees up 132KB.

I'm also pretty sure that I've had some much larger logs stored on that PLC with no memory card.

 

[Puddle]

Does this help?
https://www.plctalk.net/qanda/showthread.php?t=137603

That did help. I had it set to 720 logs, logging every 2 minutes for 24 hours maximum. So the PLC seems to reserve the data of a full size log, so even though the actual data is shown in the file size, that may only be for 1 instance with 719 in reserve.
I would have expected that data to become available once the log is closed however.

I've reduced this so the maximum number of logs won't touch the memory limit.

I'm still missing some information as to how much data is used though, as the log size is about four times larger than it should be when adding up the data contents. I can't find a resource to show what data is used.

EDIT: I've worked out where the data is going. I was thinking in terms on PLC data types, but it's saved as a CSV file. When opening in notepad, there are 217 characters which are a byte each, plus 5 bytes for the file name.