Siemens SINUMERIK 840DE sl Commissioning Manual page 621

21.8.5 Setting up the Hirth joint
If the tool spindle or the swivel axis has a Hirth joint with, for example, incrementing of 2.5°
(360°/2.5° = 144 division), you can set up the following:
Settings
MD30505 $MA_HIRTH_IS_ACTIVE
= 0
MD30330 $MA MODULO RANGE
= 360°
MD30340 $MA_MODULO_RANGE_START
= 0°
MD30501 $MA_INDEX_AX_NUMERATOR
= 360°
MD30502 $MA_INDEX_AX_DENOMINATOR
= 144
Swivel axis has Hirth joint
$NT_CNTRL[n]
Bit 5 = 1
Tool spindle has Hirth joint
$NT_CNTRL[n]
Bit 6 = 1
21.8.6 Different coordinate systems for milling and turning
In boring mills, the rotary table usually rotates around the Y axis (B axis). During turning, the
workpiece must rotate around the Z axis (C axis) in the G18 plane. Therefore, different
coordinate systems must be used on this machine for milling and turning.
SINUMERIK Operate (IM9)
Commissioning Manual, 12/2017, 6FC5397-1DP40-6BA1
Tool spindle / swivel axis is not a real Hirth axis
Effective for modulo axis
Effective for non-modulo axis
Defines the value of the denominator for calculation of the distances between two indexing
positions for equidistant positions. For modulo axes, this is therefore the number of in‐
dexing positions.
Swivel axis has a Hirth joint
[n] transformation name
Tool spindle has a Hirth joint
[n] transformation name
Technologies and cycles
21.8 Turning on milling machines
Axis is indexing axis with Hirth joint
Size of the modulo range
Start position of the modulo range.
Indexing axis, numerator for equidistant positions
Indexing axis, denominator for equidistant posi‐
tions
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