PLC5 Migration to CLX - Logic Question

[Briankr32]

The attached files shows a rung modified by the Migration Tool. Can anyone explain the purpose of the added parallel branch? I figure it has to do with the data types changing from INTs to DINTs during conversion, but I don't see how adding the MOV and FAL instructions affects the original FBC instruction.

 

[thingstodo]

The attached files shows a rung modified by the Migration Tool. Can anyone explain the purpose of the added parallel branch? I figure it has to do with the data types changing from INTs to DINTs during conversion, but I don't see how adding the MOV and FAL instructions affects the original FBC instruction.

Just a guess - I have not investigated - but the FBC may not work exactly the same way in the PLC5 and the ControlLogix. I don't see why that might be ... I have used FBC in ControlLogix and it worked as I expected from my previous PLC5 experience ...



I agree that the added branch does not add any value, or correct anything that is obvious

 

[Briankr32]

Okay, thanks. I'm thinking I just need to double the length to 320 to account for the array now being a DINT.

 

[drbitboy]

Okay, thanks. I'm thinking I just need to double the length to 320 to account for the array now being a DINT.

This assumes the rest of the code only uses bits 0-15 of each element of the DINT array. Also, the FBC will be comparing bits 16-31 of each element even though they are not used elsewhere, so it might be worth explicitly assigning zeros to those high bits.