Siemens CPU 948 - Page 205

In the first line, the information shown below is available:
Information Meaning
BLOCK NO Type and number of the block that called the
faulty block
BLOCK ADDR Absolute start address of the calling block in
the program memory
RETURN ADDR Absolute address of the first STEP 5 operation
of this block in the user memory.
REL ADDR Relative address (= difference "RETURN
ADDR - BLOCK ADDR") of the next
operation to be processed in the calling block.
(You can display relative addresses on a
programmer in the mode "disable input"/key
switch and with S5-DOS from Stage IV
upwards using the function key "addresses").
DB NO Number of the last data block opened in the
calling block
DB ADDR Absolute start address in the program memory
of the last data block opened in the calling
block (address of data word DW 0)
Example
Evaluating the BSTACK function:
BLOCK NO BLOCK ADDR RETURN ADDR REL ADDR DB NO DB ADDR
PB 3
PB 2
PB 1
OB 1
OB 66
1)
OB 63
OB 62
OB 61
00090
00050
00040
00010
E2B10
E0FC0
E0490
E0010
98
51
41
11
E2C40
E12FA
E0CBE
E0273
00008
00001
00001
00001
00130
0033A
0082E
00263
0
0
0
0
0
0
0
0
1) The blocks executed before OB 1 are internal blocks belonging to the system program (the BSTACK is structured
chronologically).
In the example, PB 3 called the faulty block at relative address
"00008 - 1 = 00007".
During the jump to this faulty block, no data block was open.
Error Information
CPU 948 Programming Guide
C79000-G8576-C848-04
5 - 7