Rotary Axis Function; Corresponding Data; Functional Description - Siemens SINUMERIK 840C Installation Instructions Manual

12 Functional Descriptions

12.2 Rotary axis function

12.2 Rotary axis function

12.2.1 Corresponding data

Same data as for linear axes, plus the following additional or supplementary data:
• NC MD 344* (Rotary axis modulo value for leadscrew error compensation)
• NC MD 5052* bit 0 (No automatic generation of G68)
• NC MD 560* bit 7 (Actual-value display modulo 360°)
• ND MD 560* bit 3 (Rounding for rotary axes)
• NC MD 560* bit 2 (Rounding to whole/half degree)
• NC MD 564* bit 5 (Position control for rotary axis)
• NC MD 572* bit (Programming of rotary axis modulo 360°)
• NC MD 5002 (Input resolution)
• NC MD 1800* (Display resolution)
• NC MD 1800* (Position control resolution)
• Alarm 100* (Invalid grid spacing for leadscrew error compensation)
• Alarm 2064 (Rotary axis programming error)

12.2.2 Functional description

Different demands are made on a rotary axis, depending on the type of machine involved. The
rotary axis function is therefore subdivided into three subfunctions. These subfunctions are
activated either over the machine data or the program.
The control can be adapted to the various machine types by combining subfunctions.
"Rotary axis": NC MD 564*
NC MD 564*, bit 5, declares the axis to be a rotary axis. The display is absolute (1 rev. 360°,
2 revs 720°, etc.), as are the @ functions. However, the axis is programmed as though it were
a linear axis. The units of the axis-specific NC MD are treated differently.
-3
Unit 10 degrees for position control resolution 1/2 x 10
units.
Deactivation of automatic G68: NC MD 5052
G68 is generated by the NC automatically the first time rotary axes with modulo calculation are
programmed in a part program or the first time they are programmed after a block search, i.e.
the programmed position is approached along the shortest path.
This action is not always desirable. For this reason a new machine data bit has been
introduced for deactivating this function the first time the axis is programmed. The user can
now define how the control is to behave the first time the axis is programmed with G68, G90
or G91. Automatic generation of G68 cannot be deactivated as here the user cannot influence
the program with programming commands.
Actual-value display "modulo 360°": NC MD 560*
When this bit is set, the display is modulo, i.e. it is reset to 0 after 359.999 degrees. The axis
is programmed like a linear axis.
"Modulo programming": NC MD 572*
Programming of the rotary axis may be absolute (G90) up to max. 360 degrees. The
programmed sign defines the direction of travel. Following a program start after a block search
12–10
Bit 5
-3
Bit 0
Bit 7
Bit 2
© Siemens AG 1992 All Rights Reserved
units and input resolution 10
6FC5197- AA50
SINUMERIK 840C (IA)
09.95
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