Siemens SINUMERIK 840D sl Function Manual page 855

Axis is modulo
MD30310 $MA_ROT_IS_MODULO = 1:
Activation of this machine data allows the special rotary-axis response to be utilized. The
rotary-axis positioning response is thus defined during programming (G90, AC, ACP, ACN or
DC). A modulo 360° representation is executed within the control after the current work
offsets have been taken into account. The resulting target position within a revolution is then
approached.
The software limit switches and working-area limitations are inactive, meaning that the
operating range is unlimited (continuously-turning rotary axis).
Modulo position display
MD30320 $MA_DISPLAY_IS_MODULO
= 1
= 0
MD30320 $MA_DISPLAY_IS_MODULO = 1
Note
The modulo 360° position display should always be selected for a modulo axis (MD30310
$MA_ROT_IS_MODULO = 1).
Starting position for the modulo rotary axis
A start position, not equal to zero, can be specified in machine data for the modulo range:
MD30340 $MA_MODULO_RANGE_START.
This allows, for instance, a modulo range of -180° to +180° with a presetting of -180 in
MD30340.
The default setting of 0 (degrees) defines a modulo range of 0° - 360°.
Extended Functions
Function Manual, 09/2009, 6FC5397-1BP20-0BA0
For rotary axes, a position display with "modulo 360°"(one revolution) is often required, i.e.,
with a positive direction of rotation the display is periodically reset within the control to 0.000°
after 359.999° is reached, with a negative direction of rotation the positions are also
displayed in the range 0° to 359.999°.
Absolute-position display would, in the case of a positive direction of rotation, for example,
result in +360° being displayed after one revolution, +720° after two revolutions, etc, in
contrast to the modulo 360° display. In this case, the display range is limited by the control in
accordance with the linear axes.
R2: Rotary axes
13.2 Modulo 360 degrees
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