Technical data

Table Of Contents
Organization Blocks
System Software for S7-300/400 System and Standard Functions - Volume 1/2
1-62
A5E00709327-01
Variable Type Description
OB121_BLK_NUM WORD Number of the block with the MC7 command that
caused the error (no valid number is entered here for an
S7-300)
OB121_PRG_ADDR WORD Relative address of the MC7 command that caused the
error
(no valid value is entered here for an S7-300)
OB121_DATE_TIME DATE_AND_TIME DATE_AND_TIME of day when the OB was called
The variables dependent on the error code have the following meaning:
Error code Meaning
B#16#21:
OB121_FLT_REG:
BCD conversion error
ID for the register concerned (W#16#0000: accumulator 1)
B#16#22:
B#16#23:
B#16#28:
B#16#29:
OB121_RESERVED_1:
Area length error when reading
Area length error when writing
Read access to a byte, word, or double word with a pointer whose bit
address is not 0.
Write access to a byte, word, or double word with a pointer whose bit
address is not 0.
Incorrect byte address. The data area and access type can be read from
OB121_RESERVED_1.
Bits 7 to 4 access type.
- 0: bit access,
- 1: byte access,
- 2: word access,
- 3: double word access
Bits 3 to 0 memory area:
- 0: I/O area
- 1: process-image input table
- 2: Process-image output table
- 3: bit memory
- 4: global DB
- 5: instance DB
- 6: own local data
- 7: local data of caller
B#16#24:
B#16#25:
OB121_FLT_REG:
Range error when reading
Range error when writing
Contains the ID of the illegal area in the low byte (B#16#86 of own local
data area)
B#16#26:
B#16#27:
OB121_FLT_REG:
Error for timer number
Error for counter number
Illegal number