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Error Diagnostics
Address Calculation (necessary only when using the PG 605U programmer)
To make program corrections, you need the address of the statement that caused the malfunc-
tion, relative to the particular block (relative address).
Determine the faulty block by comparing the STEP address counter value (SAZ value) and the
"DIR PC" display.
The difference between the SAZ value and the block start address gives the relative address of the
error (see Figure 5-3).
ISTACK Byte
STEP Address
Counter
The absolute address B042 is greater
than the start address of PB7.
Therefore, the illegal statement is
in PB7.
Calculation of the relative address:
Consequently, "0006" is the address of the statement in PB7 before which the CPU went
into the "STOP" mode.
Figure 5-3. Calculating an Error's Relative Address
Note
The programmers (with the exception of the PG 605) calculate the relative error
address automatically and display it in the ISTACK.
The interruption point, block type, block number and relative address calculated by
the programmers to be the cause of error may, under certain circumstances, be
wrongly calculated and displayed in the case of the CPU 944*.
For this reason, the CPU 944 writes the program interruption point into DB0, parallel
to the ISTACK entry. DB0 is generated automatically by the CPU 944. You can detect
the correct interruption point with the help of the "STATUS VAR" and "FORCE VAR"
programmer functions.
Example:
STATUS VAR/FORCE VAR screen form on the programmer
DB 0
DW 0
DW 1
DW 2
*
Error removed in the case of:
- S5-DOS Stage 3, basic package V1.1
Display of an Illegal Statement
You can use the "SEARCH RUN" programmer function to find specific program locations (see
Section 8.3). You can use this function to look for the relative address of an error.
5-14
25
26
B0
42
B042 - B03C=0006
KS =
..
Block type in KS format
KF =
...
Block number in KF format
KH =
....
Relative address of the interruption point in the
block
S5-115U Manual
DIR PC
Block
Start Address
PB0
B018
PB7
B03C
OB1
B00A
EWA 4NEB 811 6130-02b
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