Siemens SINUMERIK 840D sl Function Manual page 1225

Procedure
Sequence of the implicit transition to axis mode (M70 is not programmed in the part program):
● Transition from speed control mode (M3, M4, M5, SPCOF, ...) to axis mode:
The transition is detected internally by the control, and an intermediate block is inserted in
front of the block which requests the axis mode. The block created contains the M70
functionality. The execution duration for this block is more or less the same as the time
required to execute a programmed M70 block. Differences may arise in the event of short
switchovers when the spindle is stationary (no braking time) if the implicit generation and
output of the auxiliary function M70 to the PLC is dispensed with (see MD35035).
● Transition from positioning mode (M19, SPOS, SPOSA) to axis mode:
The transition is executed immediately and without the generation of an intermediate block.
Configured accordingly (see MD35035), the auxiliary function M70, which is generated
implicitly, is output to the PLC when the block in which the spindle has its axis mode is
loaded.
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 done using 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.
Constraints
Synchronized actions
Basic Functions
Function Manual, 01/2015, 6FC5397-0BP40-5BA2
Value Meaning
0 No auxiliary function output to the PLC in the case of M70 functionality which is
generated inside 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.
S1: Spindles
16.2 Modes
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