Siemens SINUMERIK 840D sl Function Manual page 839

NCK/PLC signals
The group of signals from the NCK to PLC includes:
● Actual values of the digital and analog I/O signals of the NCK
● Ready and status signals of the NCK
Also output in this group are the HMI handwheel selection signals and the status signals.
The signals for handwheel selection are decoded by the basic program and entered in the
machine/axis-specific interface.
Digital/analog I/Os of the NCK
The following must be noted with respect to the digital and analog I/Os of the NCK:
Inputs:
● All input signals or input values of the NCK are also transferred to the PLC.
● The transfer of signals to the NC part program can be suppressed by the PLC. Instead, a
signal or value can be specified by the PLC.
● The PLC can also transfer a signal or value to the NCK even if there is no hardware for this
channel on the NCK side.
Outputs:
● All signals or values to be output are also transferred to the PLC.
● The NCK can also transfer signals or values to the PLC even if there is no hardware for
this channel on the NCK side.
● The values transferred by the NCK can be overwritten by the PLC.
● Signals and values from the PLC can also be output directly via the NCK I/O devices.
Note
When realizing the digital and analog NCK I/Os the information contained in the following
documentation must be taken into account:
References:
Functions Manual Extended Functions; Digital and analog NCK I/Os (A4)
Signals PLC/Mode group
The operating mode signals set by the machine control panel or the HMI are transferred to the
operating mode group (BAG) of the NCK. These apply to all NCK channels. Several mode
groups can be optionally defined in the NCK.
The mode group reports its current status to the PLC.
Basic Functions
Function Manual, 01/2015, 6FC5397-0BP40-5BA2
P3: Basic PLC program for SINUMERIK 840D sl
13.9 Interface structure
839