Return at end of function block

Just wondering what the consensus is on this,
50% of programs I see, function blocks are ended with a return instruction, though if it wasnt there the program would return anyway.
Is this just a good practice or is it actually needed in some cases at the end of the block?

I would use return only if I needed to exit before the natural end of the block.

I've been using FBD language for nearly 30 years and in Logix since shortly after it became available and have never one used a Return block.


I agree with L D[AR2,P#0.0], it seems like it should only be used if you need to jump out of the FBD early, I can't think of a reason to do this but that doesn't mean other can't. I'm not sure exactly how it works, but it could be incredibly frustrating for someone adding changes if their changes were after the Return without their knowledge. Likely the only way to know would be to have the block execution order option turned on, which I never see at customer sites and seldom do myself.

This is what I thought, the fact it works without tells me that its not needed but I see it often enough to question it. I used to program a lot of C and that was the same deal, only return instruction when returning early.
Thanks for the sanity check

Many will disagree with me, but I have found the plc programs run better with the return statement in every subroutine.


no, it doesn't make since, but, that's my 2 cents and I have this statement on all subroutines.


james

Define "better" - faster?

I took ownership of a plc5 and some slc 500 plc's years, ago.
lots of subroutines with no end statements.
the programs seemed to be very slow at times and even appeared to pause during a cycle. I started adding return statements to the logic at the end of the subroutines on several of the plc's and the programs reacted faster and the pause in the cycles went away. since that time, I add the return statements to all subroutines.


James