Help deciphering this code

So I'm not familiar with ADD instructions. The A part of this instruction is a can count going into a lid seamer. The B part is the system variable I assume.
The code is checking to see if the same can that enters is leaving (acknowledging a knocked over or missing can) because I assume it's comparing it to the A).
With The NEQ instr. if the DINT1 doesn't equal 0 then if all other code is true then M30 is true thus starting the CTD time which is preset to 1 (?) and then latching an alarm bit...The preset from the Mov instr below is not moved when the XIC is true but is when it's false.

Thoughts? Let me know if the attached is not legible.

Thanks

I presume you mean the AND instruction. The A argument is being used as a shift register with each '1' indicating a can at a particular position in the process. The B argument indicates exactly which position this rung is concerned with. If the result is zero then there was no can at that particular position. If not zero then there was one there. Without seeing the code which affects the shift register you can't tell if the shifting was left-to-right or right-to-left though the second one is more common. It also can't be determined what event triggers the shifting (time, a pulse possibly from an encoder)

Bernie--

thanks and yes, it's an AND instruction.
The trigger is a proximity switch indicating the first can. The out feed has a prox as well.
When the seamer starts and the first can passes the prox I see all the 0s turn to ones as it begins to fill. The lone '1' in the B argument (I'm assuming this is the position that we are worried about) is what we are comparing so the 1's which fill the A are compared with the number in the B .

The purpose of this is to ensure what goes in comes out, correct?
I don't really understand the purpose of the CDT.

Does that help?

The purpose of the AND instruction is to identify the presence of an item at the particular position in the shift register. I haven't tried to determine the purpose of the rest of the code.

bernie_carlton said:

The purpose of the AND instruction is to identify the presence of an item at the particular position in the shift register. I haven't tried to determine the purpose of the rest of the code.

Click to expand...

So in comparison to the A argument, B is looking for a 1 to be in the 10th spot for the right? Thanks for your help...