Siemens CPU 948, Programming Manual

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Result following copying
and duplicating After the function has been executed correctly and error-free, the
system program sets the RLO to ’0’ and clears the condition code bits
CC 1 and CC 0.
Calling OB 254/255 changes the contents of ACCU 1 to ACCU 4.
The BR register is retained.
Possible errors and
warnings when copying and
duplicating
If an error or warning occurs, the system program stops processing
OB 254/255 and continues program execution at the next STEP 5
operation. It also sets the RLO to ’1’ and writes an ID to ACCU-1-LL
(refer to Table 6-18).
If the function is aborted due to a warning, it may be possible to run
OB 254/255 correctly by calling the special function again (if
necessary, repeated several times).
In the following situation, OB 254/255 is aborted with a warning:
an OB 124, OB 125, OB 254 or OB 255 has been called during the
last 10 ms. (During a period of 10 ms, however, only one special
function OB call is permitted. This prevents multiple calls for the OBs
listed above preventing the interface to the PG from being processed.)
Condition code bits
following copying and
duplicating
After OB 254/255 is called, you can see whether the special function
has been carried out correctly or whether it was stopped by an "error"
or "warning" based on the result of logic operation and the condition
code bits CC 1 and CC 0. The result can be evaluated by conditional
jump operations.
Result codes
RLO CC 1 CC 0 Meaning Scan
0 0 0 Special function correctly
processed JB
JZ
1 1 0 Special function aborted
with "warning" JB
JP
JN
1 0 1 Special function aborted
with "error" JB
JM
JN
Table 6-20 Result codes for OB 254/255
OB 254/255: Copy/Duplicate Data Blocks
CPU 948 Programming Guide
C79000-G8576-C848-04
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