Siemens SINUMERIK 840D Function Manual page 760

S1: Spindles
18.2 Operating modes
Output of auxiliary functions to PLC
The implicit transition to axis mode can be notified to the PLC in the form of an auxiliary function
output.
Activation/deactivation
The activation/deactivation of this functionality is performed via the machine data:
MD35035 $MA_SPIND_FUNCTION_MASK (spindle functions)
Bit
20
Note
An auxiliary function M70 which is programmed in the part program is always output to the PLC.
Properties
The properties of the implicitly generated auxiliary function output M70 are "Quick" and "Output
during motion". These properties are fixed settings and are independent of the M70
configuration in the auxiliary-function-specific machine data (MD..._$M..._AUXFU_...).
M70 is only generated once during transition to axis mode. No further M70 auxiliary functions
are generated and output in adjacent blocks in which the spindle is operated as an axis. M70
is not implicitly generated and output again until axis mode is exited via, for example, SPOS,
M3, M4, M5, SPCOF, etc. and following a renewed transition to axis mode.
Supplementary conditions
Synchronized actions
When the spindle is programmed as an axis in synchronized actions, it is essential to continue
making provisions in the application to ensure there are criteria for the transition to axis mode.
If the spindle is in speed control mode, the instruction M70 or SPOS must be programmed prior
to programming as an axis. Otherwise alarm signals occur during axis programming.
FC 18
As with synchronized actions, transition to axis mode must also be performed on the application
side in FC 18, e.g. through a preparatory positioning instruction. Otherwise, the FC 18 call is
acknowledged with an error bit in the FC 18 status word.
No auxiliary function M70 is implicitly generated in the event of transition to axis mode through
programming via FC 18.
Examples
Example 1:
Part program: Transition from rotating spindle to axis mode
760
Value Meaning
0 No auxiliary function output to the PLC in the case of M70 functionality which is
generated in the control.
1 In the case of M70 functionality which is generated inside the control, the auxiliary
function M70 is generated and output to the PLC. The address extension corre‐
sponds to the spindle number.
Axes and spindles
Function Manual, 06/2019, A5E47437747B AA