Conditional Block End (BEC) by S7-1500 in TIA Portal

spandy16 said:

I had migrated my software from S7-300 controller to S7-1500 controller in TIA Portal. Afterwards I got an error in one FB during compilation, saying "RLO is not initialized". The code was as follows,

NW1: condition 1, condition 2 then JMP: END

------------
------------
NW X: END: NOP 0
BEC

My question, is it possible that I use a RET instruction directly in the first RUNG with the conditions and remove the BEC code?

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L D[AR2 said:

Is there any code after the BEC, if not use BEU

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Manglemender said:

That does sound logical but why was the jump there in the first place? It could have been written Condition 1, condition 2 etc BEC. In S7 classic, the JP instruction does not set the status of RLO so I guess that the same applies to TIA. If the original jump instruction was JC then RLO is set to 1 when JC is executed so you can write:

Code:

A I xxx
O M yyy
JC M001
S M zzz
JU END
M001: R M zzz
END: NOP 0

Nick

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KalleOlsen said:

If the 1500 works like the 300/400 (which I don't know ...yet), it is good practice to end all blocks with

SET
SAVE

This sets the ENO (and BR) to TRUE and you can link other blocks when used in LAD(KOP) and FBD(FUP).

Kalle

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PeterW said:

In all my years of programming S7, I never once did SET, SAVE at the end of a Function. I never used it to continue code outside the block, which I believe is the only time you would do that.

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