slc 5/04 div instruction problems

I had a wierd problem today while using a brand new (a few weeks old) slc 5/04. Well I was trying to us the divide instruction to get the the speed in percent that the motor was running so that I could transfer it to a PV. Well this is what I did
Source A F15:0 with a value of 2638.06
Source B value of 3450 (constant variable)
Dest: F15:80

Well what my actual problem was I tried using this instruction just like it is in something like Lad 9- PV and it would not work. my destination would have a value of zero. I copied the rung then deleted it and placed it in Lad-2 Main and it works perfect. My first guess was that I was trying to overwrite it thinking maybe it was already in use which it was not in use, but then It worked when i put it in the first Lad. Seems pretty wierd to me maybe some of you could shed some light on this for me as to possibilies as to why this wouldnt work in one Lad but then work in another.
thanks
Dallas

JSR

Make sure that somewhere in LAD2, you have a JSR 9 (jump to subroutine 9)

already did

I made sure i had ajsr going to that lad

Yes, but is the JSR being called? Unless it's unconditional, check that the rung is true...

Other 'stuff' to look for: Jumps, MCR instructions, or whatever else might be causing your DIV rung (or the JSR rung in File 2) to get skipped.

beerchug

-Eric

I have done it once........

Could it be possible that the rung you added to file 9 was after the "return" or "end" instruction

This mistake won't give you an error message.

I have done this once....