Siemens SINUMERIK 840Di Function Manual page 1585

Maximum encoder limit frequency undershot
If the maximum encoder frequency limit has been exceeded and the speed subsequently
falls below the maximum encoder limit frequency (smaller S value programmed, spindle
offset switch changed, etc.), the spindle is automatically synchronized with the next zero
mark or the next Bero signal. The new synchronization will always be carried out for the
active position measuring system that has lost its synchronization and whose max. encoder
limit frequency is currently undershot.
Special points to be noted
If the following functions are active, the maximum encoder frequency cannot be exceeded:
• Spindle positioning mode, axis mode
• Thread cutting (G33, G34, G35)
• Tapping without compensating chuck G331, G332 (does not apply to G63)
• Revolutional feedrate (G95)
• Constant cutting rate (G96, G961, G97, G971)
• SPCON
2.6.6 End point monitoring
End point monitoring
During positioning (the spindle is in positioning mode), the system monitors the distance
from the spindle (with reference to the actual position) to the programmed spindle position
setpoint (end point).
For this to work, in machine data:
MD36000 $MA_STOP_LIMIT_COARSE (exact stop limit coarse)
and
MD36010 $MA_STOP_LIMIT_FINE (exact stop limit fine)
two limit values can be defined as an incremental path starting from the spindle position
setpoint.
Regardless of the two limit values, the positioning of the spindle is always as accurate as
defined by the connected spindle measurement encoder, the backlash, the transmission
ratio, etc.
Exact stop window dependent on parameter set
Various parameter-set-dependent exact stop windows can be configured.
This makes it possible to work to different levels of accuracy in axis mode and spindle
positioning. The exact stop window can be configured separately for each gear step for
spindle positioning.
Spindles (S1)
Function Manual, 08/2005 Edition, 6FC5397-0BP10-0BA0
Detailed Description
2.6 Spindle monitoring
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