Siemens SINUMERIK 840D sl Function Manual page 775

Alternatives
The channel status is "interrupted" because a channel stop signal is active. The axis is
handled analogously to the sequence description. The following two alternatives are possible
depending on the status of the axis to be controlled:
● The axis to be controlled by the PLC is not active.
● The axis to be controlled by the PLC is active.
● The channel performs an NC RESET.
Marginal conditions
The NCK must have booted.
Axes or spindles which are currently operating under the control of the NC program can be
controlled by the PLC, i.e. the axis must be started by means of static synchronized actions
or reciprocating axis as a neutral axis, concurrent positioning axis or command axis.
The NCK does not confirm acceptance of a program axis and outputs alarm 26072 "Channel
%1 axis %2 cannot be controlled by PLC".
If the value is overwritten by the value set in the options data, then a transfer to the PLC is
not possible.
Alarm 26070 "Channel %1 axis %2 cannot be controlled by PLC, max. no. exceeded" is
generated.
Relinquish axis control by PLC
Relinquish control of axis/spindle
Control of the axis/spindle is transferred via the axial VDI interface with the MC/PLC-
interface signal:
DB31, ... DBX28.7 (PLC controls axis)
Description of operational sequence:
1. PLC to NCK with NST:
2. NCK checks, whether an axial alarm is active
3. NCK checks whether a movement has been activated that is not yet ended and stops this
Extended Functions
Function Manual, 09/2009, 6FC5397-1BP20-0BA0
The Stop status is also canceled. A subsequent axis start command results directly in an
axis motion.
The Stop status is not canceled. Generate the axis status according to use case 2 "Stop
axis". Resume the axis motion according to use case 3 "Continue axis motion".
This process is asynchronous to control acceptance by the PLC. The two previously
mentioned alternatives can occur or the axis is assigned to the channel and is reset.
DB31, ... DBX28.7 (PLC controls axis) == 0
-> Relinquish control of an axis.
movement with an axial stop as per use case 2 "Stop axis/spindle".
11.3 Motion behavior and interpolation functions
P2: Positioning axes
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