Siemens SINUMERIK 840D sl Function Manual page 1700

Detailed Description
2.6 Spindle monitoring
2.6.5 Maximum encoder limit frequency
Caution
The maximum encoder frequency limit of the actual spindle position encoder is monitored by
the control (the limit can be exceeded). It is the responsibility of the machine tool
manufacturer to ensure that the configuration of the spindle motor, gearbox, measuring
gearbox, encoder and machine data prevents the maximum speed of the actual spindle
position encoder being exceeded.
Maximum encoder frequency exceeded.
If the spindle speed reaches a speed (large S value programmed), which exceeds the
maximum encoder limit frequency (the maximum mechanical speed limit of the encoder must
not be exceeded), the synchronization is lost. The spindle continues to rotate, but with
reduced functionality.
With the following functions, the spindle speed is reduced until the active measurement
system is operating below the encoder limit frequency again:
• Thread cutting (G33, G34, G35)
• Tapping without compensating chuck (G331, G332)
• Revolutional feedrate (G95)
• Constant cutting rate (G96, G961, G97, G971)
• SPCON (position-controlled spindle operation)
When the encoder limit frequency is exceeded
NC/PLC IS:
DB31, ... DBX60.4 (Homed/Synchronized 1)
or
DB31, ... DBX60.5 (Homed/Synchronized 2)
are reset for the measurement system in question and NC/PLC IS:
DB31, ... DBX60.2 (encoder limit frequency 1 exceeded)
or
DB31, ... DBX60.3 (encoder limit frequency 2 exceeded)
are set.
If the spindle is in axis mode, the maximum encoder limit frequency must not be exceeded.
The maximum velocity (MD32000 $MA_MAX_AX_VELO) must lie below the maximum
encoder limit frequency; otherwise, alarm 21610 is output and the axis is brought to a
standstill.
90
Basic logic functions: Spindles (S1)
Function Manual, 11/2006, 6FC5397-0BP10-2BA0