Siemens SINUMERIK 840D Function Manual page 195

Boundary conditions
The axis/spindle must be operating under PLC control.
The NC confirms acceptance of an axis/spindle only if an axial alarm is not active.
Description of the sequence based on use cases
Requirement
The axis/spindle is controlled by the PLC
Relevant NC/PLC interface signals
One of the axes/spindles controlled by the PLC can be influenced by the following NC/PLC
interface signals independent of the NC program:
● DB21, ... DBX6.2 (delete distance-to-go)
● DB31, ... DBX28.1 (reset)
● DB31, ... DBX28.2 (continue)
● DB31, ... DBX28.6 (stop along braking ramp)
For signal flow between the NC and PLC at the NC/PLC interface during autonomous single
operations, see Section "Control by the PLC (Page 212)".
Use case 1: Cancel axis/spindle
The behavior when canceling the axis/spindle function is the same as for "delete distance-to-
go":
DB21, ... DBX6.2 = 1 (delete distance-to-go)
Use case 2: Stop axis/spindle
The following traversing motion of the axis/spindle controlled from the main run is stopped:
● PLC axis
● Asynchronous oscillating axis
● Command axis by static synchronized action
● Superimposed motion $AA_OFF,DRF handwheel traversal, online tool offset and external
work offset.
Following axis movements of the axis/spindle are not stopped.
Axes and spindles
Function Manual, 06/2019, A5E47437747B AA
6.3 Motion behavior and interpolation functions
P2: Positioning axes
195