Studio 5000 COP (Copy)

[einnh]

Question about COP and UDT's in Studio 5000.

I have a UDT structure with various data types that is reporting (according to the properties tab in the UDT) to be 252 bytes.

If I wanted to copy this entire UDT variable into another variable with the same UDT would 252 be the number I enter at the end of the instruction?

cop(variablea,variableb,252);

The help file for COP uses the term 'elements' for what to put as the last input but it also shows a calculation for 'bytes' so I'm not sure exactly what they are referring to.

 

[einnh]

 

[bernie_carlton]

The length is in units of the destination type. So in your case it would be 1.

 

[einnh]

Thank you.

I am confused on why the documentation has a 'byte' calculation in it then.

 

[bernie_carlton]

The COPy command won't write past the end of the destination. But lets say you have an 8 element array being copied to a 10 element array of the same type. If your length is 10 then, once the COPy has copied the first 8 elements it will continue picking up whatever garbage is past the end, in memory, of the source array. The byte count is basically a sanity check. It is even more important if you are copying from one type to a different type.

 

[ASF]

The byte count is basically a sanity check

Good thing the PLC is only checking it's own sanity and not that of it's programmer, or there'd be a whole lot more faulted PLC's out there