Rockwell Automation 1336T Function Block Prog. Manual, Series A/B - Manual (Page 164)

6–2 Handling Exceptions — Faults and Warnings
1336 FORCE — 5.9 August 1995
Most function block system faults are designated for compile time
errors. The download service performs a number of tests before
starting the compile process for the purpose of avoiding compile
faults.
The most common function block system fault is likely to be an
invalid function block link error. This fault can occur during power
up, reset, a linear parameter BRAM recall, or a download and
compile operation. Handling of this particular error is covered later
in this chapter.
Function Block Warnings
Function block warnings annunciate conditions that could cause a
soft fault and stop the drive. Warnings are less severe faults. When
a warning occurs, a warning code is entered in the warning queue
and status parameters reflect the condition. A drive stop does not
occur, and drive operation is not affected. You can clear a warning
by issuing a clear warning command.
General Information about Faults and Warnings
The three mechanisms for identifying specific function block system
faults and warnings are:
❒
the function block fault read service (covered in chapter 5)
❒
the system fault queue
❒ the system warning queue
When a fault or warning occurs, an entry is logged into the
respective queue. Each entry contains a code and some descriptive
text. The fault and warning queues keep a history of 32 fault or
warning events until you clear the fault/warning queue.
To handle the faults and warnings, you need to access the system
fault and warning queues that are associated with each drive. Each
entry in the queue shows the type of fault and the time and date when
the fault occurred.