Interrupt Analysis - Siemens SIMATIC S5-100U System Manual

Diagnostics and Troubleshooting

5.2.2 Interrupt Analysis

When there is an interrupt in program processing, you can use the following table to determine the
cause of the error. The CPU always goes into the STOP mode.
ISTACK
Byte
Display
ASPFA and
10
KEIN AS
6
and NNN
9
and
26
25 and
SAZ=FFFF*
(CPU 102)
BAU
10
NAU
10
NINEU
6
NNN
9
PEU
10
STOPS
9
STS
9
STUE
9
SYS** FEH
10
*
SAZ = STEP address counter - The ISTACK bytes 25 and 26 read "1111 1111(FF)".
**
Relevant only for the PG 605U and for the CPU 103, version 8MA03 and higher.
5-4
Table 5-3. Interrupt Analysis
Cause of Error
Error during program transfer from the PG to the
PLC:
Overflow of the internal program memory during
compilation
When automatically loading the program:
- Battery is missing or dead and there is no
valid program available on the memory
submodule
Interruption in the power supply voltage to the
CPU
The program in the PLC memory is defective.
Cause:
• A power failure has interrupted one of the
following operations.
- Compress
- Block transfer from the PG to the PLC or
memory submodule to the PLC
- PLC overall reset
• Battery has been replaced while the power
was off.
• Statement cannot be decoded.
• Nesting level is too high.
• Parameter exceeds permitted limits.
• Expansion module not connected
• I/O bus malfunction
• Maximum length of shift register exceeded
• Module unknown
• Module in wrong slot
Operating mode switch on STOP
• Software stop by statement (STP)
• STOP requested by programmer
Block stack overflow: the maximum block call
nesting depth (16) has been exceeded.
DB1 parameter setting error
S5-100U
Remedy
Shorten program.
Compress memory.
Replace the battery and
recreate the program, or
load the program again.
Perform an overall reset
and load the program
again.
Eliminate program
errors.
• Check the power
supply in the
expansion unit.
• Check the
connections.
• Check the module
slots.
Set to RUN
Eliminate program
errors.
Correct DB1.
EWA 4NEB 812 6120-02b