Save current PLC state general

[nickegeson]

Dear forum,

I have earlier worked with RSLogix 5000 and I remember there was a function in the software that made it possible to save the current state of the PLC to review later offline.

If you for example have an error that make the Equipment stop without any known reason but possible to reset and restart it is very convenient to just save the state for offline troubleshooting and get the production up and running directly without taking hours of production time for troubleshooting.

Now I mainly work with Siemens S7:s (Simatic manager and TIA up to ver 15.1) and Codesys based Schneider PacDrive.

Anybody knows if there is a similar function in these systems? Or if there is a 3rd party program maybe that have these possibilities?

// Niklas

 

[JeremyM]

I think the function you’re alluding to is uploading tag values upon save. I’m not intimately familiar with Siemens nor Codesys, so I hope this helps.

 

[parky]

On the older S7 only DB's will save the state, not sure about TIA, so M bits (flags or in RW laguage B:x/x) are non-retentive and are not downloaded to/from PLC. If I remember correctly, in S7 you have to drop the on-line (DB files) to the off line or the structure will be lost. So if you need to save the state then use Data block elements i.e. DB10.DBX0.0 (bit) for internal contacts as M (F) bits are reset on run or start up.
Forgot to mention in S7 the M/F etc. is the display language F used to be English & M was German and some other languages.

 

[Lare]

On TIA you can save snapshot of all DB-values whit one mouse button click.

 

[parky]

Yes I believe you can but I suspect even in TIA you cannot save the status of Flags (M bits) like you can on RSL.

 

[Lare]

Yes I believe you can but I suspect even in TIA you cannot save the status of Flags (M bits) like you can on RSL.

On new TIA project Merkers should avoided as much as possible.
No need to use them.
Or if necessary, then couple copy blocks for copying bits and words to DB-areas would save also merkers data.




If you need to automate saving data just before stop, you can add DB-blocks for saving and update from original DB-areas to new DB-areas after CPU have been running certain time.
Maybe need also bit, which is resetted at CPU start and disables saving values.
That way you can go online after CPUs restarted and you see values which were saved just before CPU stop. Afte you have taked snapshot of this saved data, you can set saving bit and PLC updates new data to DB-areas until new stop.

 

[parky]

Yes I used to do that in S5, copy the Markers (flags) into a DB at the end of scan and copy them back In the start up OB.

 

[Lare]

Merkers can selected to be retentive.
Snaphot only takes values of DB-areas which could be what OP asked.

 

[parky]

I don't think so I believe he wants a snapshot of B bit equivalent as well just like RSL does (well on the old 500), on a save if on-line it will ask if you want to save the the status of all devices.

 

[Jim3846]

If I remember Step 7 siemens I thought you could make a data table and upload values that you want to see at that time. But the whole program, I thought there was a feature where you upload all data values to offline.