Technical data

Parameters 1. ACCU-1-L-L
Number of the data block to be shifted or duplicated,
permitted values: 0 to 255
(0 only for DX or for
duplicating DBs)
2. ACCU-1-H-L
With the value in ACCU-1-H, you specify whether you want to shift
or duplicate a block:
ACCU-1-H-L = 0:
the data block DB (OB 255 call) or DX with the number specified in
ACCU-1-L-L is
shifted to the DB RAM
ACCU-1-H-L = number for new block,
permitted values: 1 to 255
the data block DB (OB 255 call) or DX (OB 254 call) with the
number specified in ACCU-1-L-L is
duplicated in the DB RAM and
entered in DB 0 with the number stored in ACCU-1-H-L.
The values for ACCU-1-L-H and ACCU-1-H-H are not considered by
OB 254 and OB 255 and are therefore not significant for assigning
parameters to the OBs.
Possible errors
•• The data block to be shifted does not exist (OB 19).
•• The block already exists in the DB RAM (OB 31).
(therefore only execute the function once, ideally during the
start-up).
•• Not enough memory space in the DB RAM (OB 31).
In the event of an error, the function is not executed. The system
program detects a runtime error and calls
OB 19 or OB 31. How the
CPU reacts to the error depends on the way in which OB 19 or OB 31
are programmed (see Section 5.6.2).
If OB 19 or OB 31 is not programmed, the CPU goes into the stop
mode. In both cases, ACCU 1 contains an error identifier that defines
the error in greater detail.
OB 254, OB 255: Transferring a Data Block to the DB RAM
CPU 928B Programming Guide
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