You know, Step 7 has several ways to return results to caller block.
As I know,
1. RET_VAL
This can return value, but caller block must check it by comparator to confirm "success". I feel this is for returning error code.
2. OUT parameter
This can return value and UDT, but caller block must check it, too. I feel this is not for returning error code but for result of calculation.
3. ENO
This can return only Boolean. If the caller is written in LAD, Logic Blocks depending on the block will not be called on error, by putting depending Logic Blocks in the network sequentially.
I can not find out which is the best. And I think all of them can be ignored by caller Logic Block.
Please tell me, which do you use in your work?
As I know,
1. RET_VAL
This can return value, but caller block must check it by comparator to confirm "success". I feel this is for returning error code.
2. OUT parameter
This can return value and UDT, but caller block must check it, too. I feel this is not for returning error code but for result of calculation.
3. ENO
This can return only Boolean. If the caller is written in LAD, Logic Blocks depending on the block will not be called on error, by putting depending Logic Blocks in the network sequentially.
I can not find out which is the best. And I think all of them can be ignored by caller Logic Block.
Please tell me, which do you use in your work?