Unsigned Integer

Hi all,

apparently there is no data type UINT (Unsigned Integer) in RsLogix5000!
is that correct?!! or it has got a different name?
if there is no UINT then what is the way around this without using DINT instead?

thanks

Make it a DINT. If you make a tag an INT then it is still going to allocate 4 bytes of memory unless it is part of an array. Its a 32 bit system, so 32 bit chunks are more efficient.

Do not use MOV to transfer a 16 bit unsigned pattern to it. Use COP, CPW, AND, BTD, or similar appropriate instruction.

Changes in v32

They added unsigned types in version 32. They don't play very well in some cases though. You can't use the COP instruction on unsigned types, and you can't use string conversion operators on them like DTOS and STOD. they also don't support BTD and a few other operators you would expect.



Unless you have a strict need, you're better off using signed types that are larger like the previous answer recommends, or using a signed type of the same size if you're not using math operators on them.


BTD is also handy when copying unsigned data between SINT/INT/DINT and better conveys the intent than a COP instruction. It also prevents foul ups when copying array elements as COP will copy multiple source blocks to single destination blocks or vice versa if the size doesn't match.

votecoffee said:

They added unsigned types in version 32. They don't play very well in some cases though.

Click to expand...

For clarity, unsigned types were added in v32 but only for the 5580/5380 controllers (L8xE/5069).

Originally posted by votecoffee:

You can't use the COP instruction on unsigned types,...

Click to expand...

Rockwell has perpetrated some true head-scratchers in the past but this one might take the cake. COP, by design is not concerned with data type. It is a byte-by-byte duplication with no concern for conversion. Why it would have issues with an unsigned type is completely beyond me.

Keith