Siemens SINUMERIK 840D sl Function Manual page 36

A2: Various NC/PLC interface signals and functions
2.2 NC/PLC interface signals - only 840D sl
Cyclic signal exchange
The following interface signals are transferred cyclically, i.e. in the clock grid of the OB1, by
the basic PLC program:
● NC and operator-panel-front-specific signals
● Mode group-specific signals
● Channel-specific signals
● Axis/spindle-specific signals
NC and operator-panel-front-specific signals (DB10)
PLC to NC:
● Signals for influencing the CNC inputs and outputs
● Keyswitch signals (and password)
NC to PLC:
● Actual values of CNC inputs
● Setpoints of CNC outputs
● Ready signals from NC and HMI
● NC status signals (alarm signals)
Channel-specific signals (DB21, ...)
PLC to NC:
● Control signal "Delete distance-to-go"
NC to PLC:
● NC status signals (NCK alarm active)
Axis/spindle-specific signals (DB31, etc.)
PLC to NC:
● Control signals to axis/spindle (e.g. follow-up mode, servo enable, etc.)
● Control signals to drive (bytes 20, 21)
NC to PLC:
● Status signals from axis/spindle (e.g. position controller active, current controller active,
etc.)
● Control signals from drive (bytes 93, 94)
Function interface
The function interface is generated by function blocks (FB) and function calls (FC). Function
requests, e.g. to traverse axes, are sent from the PLC to the NC via the function interface.
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Function Manual, 01/2015, 6FC5397-0BP40-5BA2
Basic Functions