09.95 6 NC Machine Data (NC MD), NC Setting Data (NC SD)
6.5 Spindle-specific MD (spindle data)
Input value:
=0 static feedforward control (e.g. for AC drives with rise time<position control scan
time)
0 dynamic feedforward control (for spindles with rise time>position control scan time)
The time constant for setpoint smoothing is only injected into the setpoint branch
when feedforward control (option) is active.
Note
Normal: 1/2 rise time of the drive
As from SW 4, for 8 gear stages
Scaling factor max. speed setpoint
468*
Default value Lower input limit Upper input limit Units
10 000 1)
10 000 2)
9 000 3)
0
0
32 000 1)
20 000 2)
32 000 3)
mV 1)
0.1 % of max.
setpoint 2)
Active in
all channels of
the mode
group in STOP
Like the axis-specific scaling factor of the maximum speed setpoint value (MD 260*), the
spindle-specific scaling factor is used for the digital tachogenerator matching.
If Umax is the speed setpoint voltage at maximum motor speed, then:
Speed setpoint= Umax v [V]
Example: Umax= 8.345 V
Speed setpoint= 8 345
Factor for gain switchover
469*
Default value Lower input limit Upper input limit Units
0 1 16 000 %
Active on
Power On
In positioning mode, the spindle must be under position control in its target position. In order to
ensure steady rest of the spindle even in the case of drift, extremely low setpoint speeds with
a very high resolution must be fed to the drive actuator via the analog interface.
With some drive actuators it is therefore possible to choose a different scaling of the setpoint
speeds by applying a configurable terminal signal.
Allowance must be made in the control for this change of scaling in the drive actuator so that
the overall effective gain factor remains unchanged. To achieve this, the amplification factor
(gear independent, MD 435* to 442*) must be matched to the new scaling.
The factor for gain switchover is
1
MD 469* = ––– N being the scaling factor in the drive actuator
N
Notes
• Switchover of the gain factor is activated by setting the SWITCHOVER GAIN FACTOR
interface signal. This signal must always be set together with the terminal signal.
• Entering the value 0 in MD 469* is equivalent to inputting the value 100. In neither of the
two cases is the gain factor specified in MD 435* to 442* changed.
_______
1) Up to SW 2
2) As from SW 3
2) As from SW 4
© Siemens AG 1992 All Rights Reserved 6FC5197- AA50 6–79
SINUMERIK 840C (IA)