Siemens SINUMERIK 828D Function Manual page 413

System function
Nibbling
Nibbling
Nibbling
Nibbling
Nibbling
( The value can be changed.
)
Significance of the bits
Bit Meaning
0 Acknowledgement "normal" after an OB1 cycle
An auxiliary function with normal acknowledgment is output to the NC/PLC interface at the beginning of the OB1
cycle. The auxiliary function-specific change signal indicates to the PLC user program that the auxiliary function is
valid.
The auxiliary function is acknowledged as soon as organization block OB1 has run once. This corresponds to a
complete PLC user cycle.
The auxiliary function with normal acknowledgment is output in synchronism with the part program block in which it is
programmed. If execution of the parts program block, e.g. path and/or positioning axis movements, is completed
before acknowledgment of the auxiliary function, the block change is delayed until after acknowledgment by the
PLC.
In continuous-path mode, a constant path velocity can be maintained in conjunction with an auxiliary function with
normal acknowledgment, if the auxiliary function is output by the PLC during the traversing motion and before
reaching the end of the block.
1 Acknowledgement "quick" with OB40
An auxiliary function with quick acknowledgment is output to the NC/PLC interface before the next OB1 cycle. The
auxiliary function-specific change signal indicates to the PLC user program that the auxiliary function is valid.
The auxiliary function is acknowledged immediately by the PLC basic program in the next OB40 cycle.
Acknowledgment of the auxiliary function is not confirmation that the corresponding PLC user function has been
executed. The auxiliary function is still executed in the OB1 cycle. Next output of the auxiliary functions to the PLC is
therefore not possible until after this OB1 cycle has run completely. This is noticeable in continuous-path mode (drop
in path velocity) especially if auxiliary functions with quick acknowledgment are output in several consecutive part
program blocks.
With auxiliary functions with quick acknowledgment, it cannot be guaranteed that the PLC user program will respond
in synchronism with the block.
Note
Parameterization of the output behavior of auxiliary functions as "quick auxiliary functions" is only possible in
conjunction with user-defined auxiliary functions.
Basic Functions
Function Manual, 09/2011, 6FC5397-0BP40-2BA0
Index <n>
Output behavior, bit
28 0 0 0 (0) 0
29 0 0 0 (0) 0
30 0 0 0 (0) 0
31 0 0 0 (0) 0
32 0 0 0 (0) 0
0 0 (0) (0) (0) (0) (0) (1) (0)
0 0 (0) (0) (0) (0) (0) (1) (0)
0 0 (0) (0) (0) (0) (0) (1) (0)
0 0 (0) (0) (0) (0) (0) (1) (0)
0 0 (0) (0) (0) (0) (0) (1) (0)
H2: Auxiliary function outputs to PLC
8.2 Predefined auxiliary functions
0 (0) (0) (0) (1)
0 (0) (0) (0) (1)
0 (0) (0) (0) (1)
0 (0) (0) (0) (1)
0 (0) (0) (0) (1)
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