Ladder Utility Failure

[TT_ZX]

Does anyone have Ladder Utility Failures (SB399)?  I am getting value 18 (Logic: Test Bit (in vector)) and 22 (Vector: Store) repeating every second in SI26.  I haven't noticed this causing problems in my program so I'm not sure what to make of it.  Should I be concerned?

[Eyal Koren]

Hi,

These specific Utility failures suggest overflow in values related to the function blocks mentioned in SI26:

Test Bit (#18): This utility is limited to a maximum of 255 bits in the vector (which are 16 MI's or 8 DW's). Exceeding this value is the cause of this issue.

Vector Store (#22): Utility failure will occur if the vector being reference is longer than the maximum number of operands in Visilogic (for instance - MI4095).

 

It seems like you are misusing these functions. I'm surprised that these did not affect your application.

Anyway, I hope this helps.

[TT_ZX]

Thanks eyals.  There is quite a bit of data collection and manipulation going on just for HMI display purposes so its probably not in the code that actually does stuff.  I'm guessing something is going wrong with an offset or vector length calculation.  Now I now what to look for and where to look for it so that's a big help.