6 NC Machine Data (NC MD), NC Setting Data (NC SD) 04.96
6.6.2 Spindle-specific MD bits (spindle bits)
•Control mode
The last drift compensation value to be derived is also maintained in
control mode (M3/M4/M5).
• C axis mode
The NC axis drift machine data MD 272* applies here; the compensation
calculated by the function ”Automatic drift compensation with M19” has no
effect here.
Note:
• If the M19 area is deselected the derived compensation value remains
active.
If the NC spindle drift machine data (NC MD 401*) is altered, the internal
compensation value is not deleted, i.e. M19 has to be executed again to
adjust the compensation value to the new machine data.
• The internal compensation value is maintained on warm restart.
76543210
Bit No.
NC MD
522*
Switch over
parameter
groups
separately
Switching
off with
braking
ramp
Multiple
assignment
setpoints
Number of
encoder
pulses
(611D)
multiple of
Measuring
system with
ext. zero
mark
Bit 4 Bit 4=0 Active for digital and analog drives
The parameter set of digital spindles is switched over by presetting the actual
gear stage in DB 31, DR K + 1, Bit 0...2. The control signals in DB 31, DR K
+ 74, bit 0...2 ("Parameter set number") have no effect.
Bit 4=1 The parameter set number of the digital spindle is switched over via PLC
control signals DB 31, DR K + 74, bit 0...2 irrespective of the actual NC gear
stage.
Bit 3 Bit 3=0 No braking ramp when switching off the rpm servo control.
The speed setpoint immediately drops to 0 when the rpm servo control is
switched off. PLC control signal DB 31, DL K + 74, bit 9 ”Ramp-function
generator rapid stop”, has no effect on the setpoint assignment. (No setpoint
is output with bit 9 of DB 31 DW 74).
Bit 3=1 Deceleration with braking ramp for mode group stop
If PLC control bit DB 31, DL K + 74, bit 9 = 0, the setpoint is ramped down
to zero. Otherwise it is brought abruptly to zero as described above.
This bit is also effective in C axis mode. Braking is then executed with the
acceleration from MD 276*. Only SW 4, uses the acceleration from MD 1768*
(set of parameters); however, a value greater by the ratio of Ipo to position
control cycle must then be entered.
Bit 2 Bit 2=0 No multiple assignment of setpoint.
The control recognizes if several spindles have been assigned to the same
digital setpoint output on runup, which triggers the alarm "Parameterization
error NC MD" with service number 329.
6–128 © Siemens AG 1992 All Rights Reserved 6FC5197- AA50
SINUMERIK 840C (IA)