Siemens SINUMERIK 840D Function Manual page 741

SPOS[<n>]=ACN(...)
Approaches the position from the negative direction.
When positioning from a positive direction of rotation, the speed is decelerated to zero and
accelerated in the opposite direction to execute the negative approach.
M19 (DIN 66025)
M19 can be used to position the spindle. The position and the position approach mode are read
here from the following setting data:
SD43240 $SA_M19_SPOS[<n>] (spindle position for spindle positioning with M19)
SD43250 $SA_M19_SPOSMODE[<n>] (spindle position for spindle positioning with M19)
The positioning options of M19 are identical to those of:
SPOS = <approach mode> <position/path>
M19 is output as an auxiliary function to the NC/PLC interface as an alternative to M3, M4, M5,
and M70. The M19 block remains active in the interpolator for the duration of positioning (like
SPOS).
Part programs using M19 as a macro (e.g. DEFINE M19 AS SPOS = 0) or as a subprogram,
continue to remain executable. For the sake of compatibility with previous controls, the internal
processing of M19 (NC positions the spindle) can be disabled as shown in the following
example:
MD22000 $MC_AUXFU_ASSIGN_GROUP[0] = 4
MD22010 $MC_AUXFU_ASSIGN_TYPE[0] = "M"
MD22020 $MC_AUXFU_ASSIGN_EXTENSION[0] = 0
MD22030 $MC_AUXFU_ASSIGN_VALUE[0] = 19
Implicitly generated auxiliary function M19
To achieve uniformity in terms of how M19 and SPOS or SPOSA behave at the NC/PLC
interface, auxiliary function M19 can be output to the NC/PLC interface in the event of SPOS
and SPOSA.
The two following options are available for activating this function:
● Channel-specific activation for all the spindles in the channel via the machine data:
MD20850 $MC_SPOS_TO_VDI (Output of M19 to the PLC with SPOS/SPOSA)
Axes and spindles
Function Manual, 06/2019, A5E47437747B AA
Bit Value Meaning
0 0 If bit 19 is also set to "0" in the MD35035 $MA_SPIND_FUNC‐
TION_MASK, no auxiliary function M19 is generated in SPOS and
SPOSA. This therefore eliminates the acknowledgment time for
the auxiliary function.
1 The auxiliary function M19 is generated and output to the PLC
during the programming of SPOS and SPOSA in the part program.
The address extension corresponds to the spindle number.
S1: Spindles
18.2 Operating modes
; Auxiliary function group: 4
; Auxiliary function type: "M"
; Auxiliary functions Extension: 0
; Auxiliary function value: 19
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