09.95 6 NC Machine Data (NC MD), NC Setting Data (NC SD)
6.5 Spindle-specific MD (spindle data)
Allocated C axis
461*
Default value Lower input limit Upper input limit Units
0 0 30 –
Active on
Power On
MD 461* defines which global axis number is used to operate the spindle when it works as C
axis. This determines, for instance, which axis-specific machine data block is used.
If the value 0 is entered in MD 461, the spindle cannot be used as a C axis.
Notes
• Any change in MD 461* does not take effect until Power On.
• If a C axis is assigned to a spindle (MD 461* not equal to 0), the internal calculations are
also performed for this spindle in the measuring system resolution of the C axis. In the
event of an identical measuring system, the variable increment rating of the axis must
therefore be entered (MD 364*, 368*, 1800*).
Spindle encoder cutoff frequency
462*
Default value Lower input limit Upper input limit Units
200 0 16 000 kHz
Active on
Power On
The cutoff frequency of the spindles's actual value encoder is entered in MD 462*. The cutoff
frequency can be taken from the encoder manufacturer's specifications.
Incoming pulses from the encoder may be lost when the cutoff frequency is exceeded. In this
case actual value acquisition will not be correct. The signal ”SPINDLE STOPPED” must be
evaluated by the drive. The SPINDLE SYNCHRONIZED interface signal is cancelled.
In the case of a repeated drop below the critical frequency, the spindle is automatically
resynchronized with the encoder (hysteresis characteristic).
Note
If a separate encoder is not proivided for C axis operation, the limiting frequency of the spindle
encoder is again monitored in this operating mode.
Synchronous position offset
463*
Default value Lower input limit Upper input limit Units
0 -179.99 180.00 0.01°
Active on
Power On
Feedforward control factor
465*
Default value Lower input limit Upper input limit Units
0 0 1 000 0.1 %
Active
–
Active: During position controlled operation (M19)
The feedforward control is used to reduce the following error.
In feedforward control the partial setpoint is multiplied by the feedforward control factor and
switched directly to the spindle speed control input. The time constant entered in MD 467* is
switched to the input of the position controller directly, if it is static feedforward control, and
delayed by a PT 1 element, if it is dynamic feedforward control.
© Siemens AG 1992 All Rights Reserved 6FC5197- AA50 6–77
SINUMERIK 840C (IA)