Help with RSLogix 5000 COP instruction.

Hi,

Is it possible to use the COP instruction to copy only one element of a structure or UDT to an array with the same type as the element. Per example:

Structure:

Structure[100], with each on being comprised of:

Structure[xx].element1 (type REAL)
Structure[xx].element2 (type REAL)

My destination array would be Destination_Array[100] (type REAL)

I want to basically copy all the .element2 of my Structure into the destination array. Can I use the following COP instruction?

COP
Source: Structure[0].element2
Dest : Destination_Array[0]
Length: 100

I would also be able to do the opposite which is write from the Destination array back to each .element2 in the structure array.

Thanks

I would have to test it to be sure, but I would guess that the answer is no. The COP command is setup to copy contiguous memory blocks from one location to another.
Because the UDT's elements are not contiguous in memory, the COP would not do what you are trying to do.

I believe that you are going to have to use a series of MOV instructions with some sort of logic to loop through all of your UDTs to extract the desired element of each UDT object.

Check out the FAL instruction. The examples in the help file should get your imagination going. If the scan time can take it you can even set it to execute the entire process in one scan.

This is how I'd do it.

In the main routine:
FOR UDTtoArray I 0 99 1

In a routine called UDTtoArray:
COP Structure.element2 Destination_Array 1


Might not be the most efficient, but it's clear.

(Beats me why the forum insists on changing the I in the COP instruction to i, but I tried to change it back twice.)

Thanks everyone for the tips..

Mellis: I tried your suggestion and it works perfectly for my needs... Like you said there might be a more efficient way to do it, but this works great... Thanks a lot..