plc internal data saved upon tag event

[Kataeb]

Kindly, we are having a problem on a machine during night shifts, while no engineering tool is online.

So, we were thinking of programming some kind of internal data acquisition, inside the plc, which will save the last hundred or thousand values of some tags, starting from the problem and backward in time.
The plc will keep them in its memory.
Then, when the engineering team arrives in the morning, they can check the data which was saved just before the problem happened.
Ideally they will see it as a trace or trend.

Is this feasible with the following hardware?

6ES7515-2TM01-0AB0 , 6ES7954-8LL03-0AA0 , 6SL3040-1MA01-0AA0 , 6SL3054-0FB01-1BA0-Z F02 , 6FX2001-5QN25 , 6AV2123-2GB03-0AX0 , 6ES7155-6AU01-0CN0

 

[robertmee]

You can program this but you can't go back in time...you would need to already be recording the data up to and including the time of the event. The amount of data you can record would be dependent on the data types, the number of points, the sample rate to record, the duration to record, the current use of available memory, etc. Easiest method is to create static arrays large enough to hold the data you need. It looks like you have CF memory cards listed in your parts. There may be a means to periodically write the data to the CF card and reset the arrays to keep them smaller, if memory is an issue. I'm not an S7 guru, so one of the other more esteemed members versed in s7 will chime in.

 

[widelto]

Please Use Linux(windows), python. A raspberry Pi or similar board will be enough.
To get data from Siemens use : https://pypi.python.org/pypi/python-snap7
To save siemens data in XL format use: https://pypi.org/project/openpyxl/
Drbitboy one of us , he has good examples.

https://simplyautomationized.blogspot.com/2014/12/raspberry-pi-getting-data-from-s7-1200.html

 

[baref00t25]

Seeing that this is a Siemens 1500 you could setup a trace that triggers on an event with pre-trigger samples and then save that to the memory card.

 

[A_G]

Seeing that this is a Siemens 1500 you could setup a trace that triggers on an event with pre-trigger samples and then save that to the memory card.

I agree. Try to set up a Trace. Just be careful that the PLC memory usage is not close to capacity, because Traces use memory

 

[mk42]

Adding another vote for using the Trace function inside Portal. It triggers in the PLC, saves it in a buffer (or on the memory card), and then Portal can look at it later, with graphs and everything.


you COULD roll your own, but the built in tool is really good, so please don't.

 

[Kataeb]

Kindly , can we get some samples or guidelines to do this in Tia Portal ?

 

[L D[AR2P#0.0]]

Read the help to start:

 

[chud]

https://cache.industry.siemens.com/dl/files/128/64897128/att_896017/v1/trace_editor_function_manual_en-US_en-US.pdf

 

[tarik1978]

TIA Portal: Traces for Troubleshooting
https://www.youtube.com/watch?v=F5mjD9EEWN0