Rockwell Automation Logix5000 Controllers Controller Information and Status Programming Manual - Manual (Page 53)

Chapter 5
Access status information
The controller supports status keywords you can use in your logic to monitor
specific events.
• The status keywords are not case sensitive.
• Because the status flags can change quickly, the Logix Designer application
does not display the status of the flags. For example, even when a status flag
is set, an instruction that references that flag is not highlighted.
• You cannot define a tag alias to a keyword.
The following table lists the available key words.
To determine if Use
The value you are storing cannot fit into the destination because it is either:
•
Greater than the maximum value for the destination.
• Less than the minimum value for the destination.
Important: Each time S:V goes from cleared to set, it generates a minor fault (type 4, code 4).
S:V
The instruction’s destination value is 0. S:Z
The instruction’s destination value is negative. S:N
An arithmetic operation causes a carry or borrow that tries to use bits that are outside the data type.
For example:
•
Adding 3 + 9 causes a carry of 1.
• Subtracting 25 - 18 causes a borrow of 10.
S:C
This is the first, normal scan of the routines in the current program. S:FS
At least one minor fault has been generated.
•
The controller sets this bit when a minor fault occurs due to program execution.
• The controller does not set this bit for minor faults that are not related to program execution, such as
battery low.
S:MINOR
Introduction
Rockwell Automation Publication 1756-PM015F-EN-P – October 2014 53