Siemens S7, SFC83,84 problems

[JockeData]

Looks like the same problem but my german is a bit rusty.

http://www.sps-forum.de/simatic/40935-fehler-bei-sfc83-read_dbl.html

Looks like it has something to do with the DB changing while the SFC is in progress...I think....

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Yea, i read something like that also.

But this shouldnt be in my case. I have nothing that changes the values in my Source DB except the VAT table im using to put in values.

I have simply done like this

Created two DBs, 1 linked and 1 unlinked.
In them i have created an array with 2 INTs. So they both look the same.

Then i put in my values via a VAT table in the LinkedDB.

I activate a bit which triggers the REQ on the Write SFC to write from the LinkedDB array [0] to the Unlinked array [0].

I then deactivate that bit, change the value in the LinkedDB to 0.

Activate the bit which triggers the REQ on the Read SFC to read from the Unlinked array [0] to the Linked array [0].

So this works on my test rig but not on the actual PLC where i need it.

Edit: I saw now when i read the post one more time that it worked for him for a while if he made the PLC go from RUN to STOP and back. I have not been able to try this due to production.
Mabye i have done something so my PLC go stuck in the same mode as for this guy.

 

[Mousemania]

Do you have anything in the diagnostic buffer of the problem PLC?

 

[JockeData]

Do you have anything in the diagnostic buffer of the problem PLC?

Nope, nothing

 

[Mousemania]

Is it being called in an FB/FC? Perhaps the FB/FC is being called multiple times thereby causing the SFC to be called more than once?

(Also did you get a chance to try updating the firmware yet?)

 

[JockeData]

Is it being called in an FB/FC? Perhaps the FB/FC is being called multiple times thereby causing the SFC to be called more than once?

Its called in an FC but that FC is only called in one place in OB1.

Edit: About the firmwire. I will try a "cold reboot" tomorrow and see if that german forum post was right. If thats not working i might give that firmwire update a try.

 

[Mousemania]

Okay so according to the S7 help file error code 80C3 means "The maximum number of simultaneously active SFC 83 is currently reached" but according to this document on page 94 that same error code is described as "The required operating resources are currently occupied." It makes sense that the operating resources would be occupied when calling the SFC too often, but it seems for you that isn't necessarily the case. I'm no expert, so maybe some others can help chime in here about why else your operating resources would be occupied. Maybe check the memory of that PLC? Sounds like a cold reboot could also work though if there may be excess programs being called and got "stuck" that were bogging the PLC down? These are all guesses of course, hopefully not showing my lack of experience here too much...

 

[JockeData]

Okay so according to the S7 help file error code 80C3 means "The maximum number of simultaneously active SFC 83 is currently reached" but according to this document on page 94 that same error code is described as "The required operating resources are currently occupied." It makes sense that the operating resources would be occupied when calling the SFC too often, but it seems for you that isn't necessarily the case. I'm no expert, so maybe some others can help chime in here about why else your operating resources would be occupied. Maybe check the memory of that PLC? Sounds like a cold reboot could also work though if there may be excess programs being called and got "stuck" that were bogging the PLC down? These are all guesses of course, hopefully not showing my lack of experience here too much...

I hope you are correct. I have been thinking in the same ways all day. But as you probably know, its not easy to request a stop of production just like that

I feel like there arent many more options, and since i can get it to work on a different CPU (With the same code, dbs etc) i feel like there must only be that it has gotten "stuck" or something similar. And that hopefully it can be resolved with a reboot.

 

[JockeData]

I can gladly announce that a cold reboot did the trick. So im assuming that i have maybe changed the Source DB while still having the bit for REQ active.

Kinda bad though that there isnt a way out of this by siemens except a reboot. And i havent find any warnings about this either.

Thanks for all the help guys! I will defenitely come back here on a regular basis!