Siemens SIMATIC S5-100U System Manual page 98

Diagnostics and Troubleshooting
Calculating the Address (necessary only when using the PG 605U)
In order to be able to make program corrections, it is necessary to have the address of the
statement that led to the fault referenced to the particular block (relative address).
The faulty block is found by comparing the SAZ (STEP address counter) contents and the
"DIR PC" display.
The relative error address gives the difference between the SAZ value and the block start address.
Figure 5-3 gives you an example of how to calculate the relative error address.
ISTACK byte
STEP address counter
The absolute address EE42 is
greater than the start address for
PB7. The faulty statement is
therefore in PB7.
Calculating the relative address:
"0006" is the relative address of the statement in PB7 following the statement that
caused the CPU to go into the STOP mode.
Output of an Error Statement
Use the "SEARCH" programmer function to find certain program locations and to look for the
relative error address. Refer to your programmer manual for additional information about this
programmer function.
5-10
25 26
EE 42
EE42 - EE3C = 0006
Figure 5-3. Calculating the Error Address
S5-100U
DIR PC
Block Start Address
PB0 EE18
PB7 EE3C
OB1 EE0A
EWA 4NEB 812 6120-02b