error messege with FB

islam nasser · Nov 20, 2010

hi that i may first time to create fb in siemens S7 300 plc
i try to create a Fb(function block) to use in my programe
but while saving this messege apper

any one can help me?

PeterW · Nov 20, 2010

you need to recreate your IDB.

Delete it, open block where FB is called and cut and re-paste the FB, DB call and it will recreate the IDB, then transfer it into the PLC.

islam nasser · Nov 20, 2010

PeterW said:
you need to recreate your IDB.

Delete it, open block where FB is called and cut and re-paste the FB, DB call and it will recreate the IDB, then transfer it into the PLC.

this problem not happens when calling the Fb , it happens when i finished from writting the code of FB and try to save the FB code

L D[AR2P#0.0] · Nov 20, 2010

When ever you change the interface in an FB, you will get this message. Creating the FB is also changing the interface as previously it did not exist.

An interface change refers to a change to IN, OUT, IN_OUT and STAT variables - adding or changing a data type. Changing the temp area is not classed as an interface change.

islam nasser · Nov 20, 2010

L D[AR2 said:
When ever you change the interface in an FB, you will get this message. Creating the FB is also changing the interface as previously it did not exist.

An interface change refers to a change to IN, OUT, IN_OUT and STAT variables - adding or changing a data type. Changing the temp area is not classed as an interface change.

thanks for your reply
but please tell me your explanation to that 'When this block is
loaded, the CPU goes into the STOP mode."

PeterW · Nov 20, 2010

It means the PLC could stop, not will. It is possible if the DB is no longer valid (too short for example) then the PLC can go to stop mode if it tries to access data that does not exist in the DB in the PLC.

You need to do as I said above after saving the FB and download both blocks.

Either download when the system is stopped, therefore the PLC crashing is not a problem, or ensure OB121 is loaded into the PLC which will stop the PLC crashing on program fault.

Madman · Nov 20, 2010

PeterW said:
It means the PLC could stop, not will. It is possible if the DB is no longer valid (too short for example) then the PLC can go to stop mode if it tries to access data that does not exist in the DB in the PLC.

You need to do as I said above after saving the FB and download both blocks.

Either download when the system is stopped, therefore the PLC crashing is not a problem, or ensure OB121 is loaded into the PLC which will stop the PLC crashing on program fault.

...after saving the FB and download both blocks and instance DB

Madman · Nov 20, 2010

Also you can
1 Save you FB
2 Open OB, FB or FC where calling you modified FB, press file / Check and update Accesses, save it
3 Select both blocks and instance DB and download it to PLC

All must work without ‘CPU goes into the STOP mode’

islam nasser · Nov 20, 2010

Madman said:
Also you can
1 Save you FB
2 Open OB, FB or FC where calling you modified FB, press file / Check and update Accesses, save it
3 Select both blocks and instance DB and download it to PLC
All must work without ‘CPU goes into the STOP mode’

thanks to all for your efforts
problem is solved

i think that "Select both blocks and instance DB and download it to PLC "
is the proper solution

error messege with FB

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