Siemens S5 Block problem

Good morning All

I am just doing my first S5 job, (lots of AB and Omron experience).

We have a working machine; the parent company sent over a program from an (almost) identical machine for me to load.

I uploaded and saved current version (OB001 and PB001-003), and loaded new version. Machine does not work now. Yes, it is in RUN mode, and I tried the load both without STOPping the PLC, and after STOPping it. Yes, the addresses are identical.

One (small, I think) difference is that there are PB001-006 in the new version.

First thing that should happen is:
In PB003 - Push Start PB, conveyors come on. The original program used a self-seal rung, the new one uses a Latch/Unlatch - I know they should work identically. No, the Unlatch condition is not active - I even put a dummy bit in there to ensure that.

I can see the logic flow while monitoring, my Start PB is running to the Latch output, but the (real) output does not come on nor does the (L) stay lit when I release the PB. Again, the (U) rung is not being triggered.

If I load the original program back in, the machine works. Ergo, I am doing the transfer and RUN/STOP correctly.

I even tried modifying that PB, in the new program, to only contain -||- pushbutton -(motor); this does not work either!

Any ideas? Please?

Please check the program to see if the "latch" or "unlatch" are used in more than one place?
Can you post a copy of your project here?

Are you two twins? :nodi:

A few weeks ago I had to reset the PLC then do a download.... not sure why but it was acking something like yours... the output would be true but it would never turn on

I have posted a procedure on the rest of S5's before if you don't know how, what is you exact part number? as I have some good manuals that may help (if they are for the correct one)

EDIT: Post both programs... I have a compare program and I will see if there are any hidden bits that you are not seening

lol

Is it possible to include some screen dumps of the block?

The L and U bits are not used elsewhere. That is usually my first check.

I just had a closer look at the OB01 file, it has a conditional jump to the PB where our outputs are; the old program had unconditional. I am going to try reloading and short out/remove the conditional.

I made the jump unconditional, and it still does not work. Will try to do some screen captures for Thursday.