Siemens SINUMERIK 840D sl Function Manual page 55

Principle of the parameterization of the NC I/O in the input area
Transfer times
● Transfer of the output data from the NC to the output modules
– The output data is transferred from the NC to the output modules at the end of the current
– The transfer is only performed when at least one output data item has been written in
● Transfer of the input data from the input modules to the NC
– Time within which the cyclic request for the update of the input data (input image of the
– MD10398 $MN_PLCIO_IN_UPDATE_TIME = <update time>
– The parameterized update time is rounded up internally to the next highest multiple of
– The request for the update of the input data is sent to the PLC at the end of the
– The updated input data is available at the earliest in the following interpolation cycle.
Selection of the storage format (little/big endian)
A total of 16 KB is available for the data transfer between the NC and PLC for all NC channels.
These areas have to be managed by the user (i.e. no overlapping of the variables, not even
across channel borders).
The display of the variables within these areas depends on the setting in the machine data:
Extended Functions
Function Manual, 10/2015, 6FC5397-1BP40-5BA3
interpolator cycle.
the current interpolator cycle.
modules → NC input data) from the NC to the PLC is sent, can be set via the machine
data:
an interpolator cycle. With update time = 0, the request is transferred to the PLC in each
interpolation cycle.
parameterized interpolation cycle.
A4: Digital and analog NC I/O for SINUMERIK 840D sl
2.3 Direct I/O access via PLC
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