Siemens CPU 948 Programming Manual page 215

CONDITION CODE
CAUSE OF INTERR.
CPU 948 Programming Guide
C79000-G8576-C848-04
see Section 3.5
The following abbreviations (ISTACK IDs) indicate the most important
causes of interruptions.
Table 5-6 ISTACK IDs CAUSE OF INTERRUPTION
CAUSE OF INTERR.
ISTACK Meaning (called error OB)
ID
KB Called block not loaded (OB 19)
KDB Opened data block not loaded (OB 19)
TRAF Load or transfer error (OB 32)
SUF Substitution error (OB 27):
Processed STEP 5 operation cannot be
substituted
STUEB Block stack overflow:
Nesting depth too great; required action:
COLD RESTART
STUEU Interrupt stack overflow:
Nesting depth too great; required action:
POWER DOWN, POWER UP,
then COLD RESTART
NAU Power failure in the central controller
QVZ Timeout (OB 23/OB 24/OB 28/OB 29)
ADF Addressing error for digital inputs and outputs with
process image (OB 25)
PARE Parity error (OB 30)
ZYK Cycle monitoring time exceeded (OB 26)
STOP STOP mode caused by setting the mode selector to the
STOP position
STS STOP mode caused by STEP 5 operation 'STS' (after
executing an operation)
Control Bits and Interrupt Stack
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