Siemens SINUMERIK Series Function Manual page 49

Transfer times
Data is output from NCK ⇒ PLC (write) at the end of the interpolation cycle if at least one
data item was written.
Data is read in by transmitting a request at the end of the interpolation cycle.
The new data is available in the subsequent interpolation cycle at the earliest.
The time period within which a request is sent to the PLC, can be specified via the machine
data:
MD10398 $MN_PLCIO_IN_UPDATE_TIME
The entered time period is rounded up internally to the next highest multiple of an
interpolation cycle. If the value of this machine data is set to "0", the request will continue to
be sent to the PLC in every interpolation cycle.
Configuring
To activate the functionality, the following machine data (Power ON active) must be
configured on the NC:
● MD10394 $MN_PLCIO_NUM_BYTES_IN
● MD10395 $MN_PLCIO_LOGIC_ADDRESS_IN
● MD10396 $MN_PLCIO_NUM_BYTES_OUT
● MD10397 $MN_PLCIO_LOGIC_ADDRESS_OUT
● MD10398 $MN_PLCIO_IN_UPDATE_TIME
● MD10399 $MN_PLCIO_TYPE_REPRESENTATION
Note
The logical PLC I/O addresses entered in the machine data and the number of bytes to be
transferred must be consistent with the PLC hardware configuration. In the configured areas,
there must not be any "address gaps" in the PLC I/O expanded configuration.
Extended Functions
Function Manual, 03/2013, 6FC5397-1BP40-3BA1
Number of PLC I/O input bytes that are read directly by the NC
Logical start address of the PLC input I/O, starting at which the data is read
Number of PLC I/O output bytes that are written directly by the NC
Logical start address of the PLC output I/O, starting at which the data is written
Time period within which the data that can be read by means of $A_PBx_IN is updated
(see Section "Transfer times").
Format display of system variables $A_PBx_OUT and $A_PBx_IN (see Section "Memory
organization").
A4: Digital and analog NCK I/Os for SINUMERIK 840D sl
1.2 Access via PLC
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