Siemens S7/TIA v18: DataLogCreate output DONE is FALSE - why?...

[Mas01]

See the attached image.

The Datalog should be created when I press Report_Button_Pressed on the HMI.

This image is taken when I pressed the button with my finger (left index finger, before you ask).

Does anyone know why the output (DONE) from DataLogCreate is FALSE.

AFAIK, the DONE is only TRUE for one cycle, but that should be enough to set the flag that I have circled. Anyone know why this flag is FALSE?

Thanks

 

[Mas01]

For info, here's the "Report_DB" datablock:

 

[mk42]

I'd recommend setting up the trace function to track REQ DONE BUSY ERROR and STATUS, and then you can see what the block thinks is going on scan by scan.

 

[Mas01]

I'd recommend setting up the trace function to track REQ DONE BUSY ERROR and STATUS, and then you can see what the block thinks is going on scan by scan.

Sorry to be a pain. How do I do this? I'll check F1-help too...

EDIT: Just watching a video about it now...

 

[Puddle]

Remove the start number from your ID. It's an in/out tag so it sets itself.
That same ID needs to be used for your write block and close blocks.

Also, it will only create one log with the same name, so if successfully completed once it needs a different name to work again.

 

[Mas01]

Remove the start number from your ID. It's an in/out tag so it sets itself.
That same ID needs to be used for your write block and close blocks.

Also, it will only create one log with the same name, so if successfully completed once it needs a different name to work again.

OK thanks, I've done that now.

 

[Mas01]

I'd recommend setting up the trace function to track REQ DONE BUSY ERROR and STATUS, and then you can see what the block thinks is going on scan by scan.

I did this trace.

When I press the HMI button, the BUSY flag momentarily goes to 1. However, DONE remains at 0 throughout.

 

[mk42]

Then you definitely definitely want to include STATUS and ERROR as well, to see what the block thinks is going on.


Best guess is that you'll get an Error bit going high next scan, and a status that when you look it up in the help file indicates that the data log is already created (either same name or same ID or something). Either that or it'll yell at you for not having a memory card. 300/400/1500 always need a memory card. 1200 has some built in load memory, so it only needs the memory card for really big programs or things like data logging.


If the data log already exists, you can just start writing to it.

 

[Mas01]

Then you definitely definitely want to include STATUS and ERROR as well, to see what the block thinks is going on.


Best guess is that you'll get an Error bit going high next scan, and a status that when you look it up in the help file indicates that the data log is already created (either same name or same ID or something). Either that or it'll yell at you for not having a memory card. 300/400/1500 always need a memory card. 1200 has some built in load memory, so it only needs the memory card for really big programs or things like data logging.


If the data log already exists, you can just start writing to it.

Okay, thanks again...I'll trace more tags this time. Cheers

 

[Mas01]

Then you definitely definitely want to include STATUS and ERROR as well, to see what the block thinks is going on.


Best guess is that you'll get an Error bit going high next scan, and a status that when you look it up in the help file indicates that the data log is already created (either same name or same ID or something). Either that or it'll yell at you for not having a memory card. 300/400/1500 always need a memory card. 1200 has some built in load memory, so it only needs the memory card for really big programs or things like data logging.


If the data log already exists, you can just start writing to it.

OK @mk42, I put some extra tags on the trace.

ERROR bit is set, along with STATUS value 28672 (at time t1). See pic.

 

[Mas01]

28672 (dec) is 7000 (hex).

Which gives this error code per the S7-1200 table...

 

[Mas01]

cancel that....

The TOP of the brown bar is 32915 (8093 hex).

"Data log already exists"...so why is that an error?

 

[mk42]

cancel that....

The TOP of the brown bar is 32915 (8093 hex).

"Data log already exists"...so why is that an error?

You're asking it to create the data log. It can't because it already exists. From a process standpoint, that means you're good, move on to the next step.


I'd say change your logic so that it doesn't try to create the data log every time, and trigger the write from the HMI button instead. at least for testing purposes.

 

[Mas01]

You're asking it to create the data log. It can't because it already exists. From a process standpoint, that means you're good, move on to the next step.


I'd say change your logic so that it doesn't try to create the data log every time, and trigger the write from the HMI button instead. at least for testing purposes.

Ah, I think the penny's finally starting to drop...

Yes, that HMI button press going into the DataLogCreate is the wrong thing to do. The user will be pressing that button several times a day when wanting to WRITE to the datalog.

A new datalog doesn't need to be created for each press of the button.