Siemens SINUMERIK 840C - Manual (Page 263)

6 NC Machine Data (NC MD), NC Setting Data (NC SD) 09.95
6.5 Spindle-specific MD (spindle data)
To activate feedforward control set option (6FC5 150-0AS02-0AA0). 1)
The feedforward control factor is adapted to the machine stability and the resulting
acceleration/deceleration of the spindle. The degree to which the following error is reduced
depends on the feedforward factor.
A factor of 1000 reduces the following error almost to zero in the stationary state. However,
this setting will cause overshooting. If this is a problem you can enter a lower value and enter
the time constant in MD 467*.
See Section entitled ”Functional Descriptions”.
Note:
As from SW 4, for 8 gear stages
Position controller clock pulse spindle 466*
Default value Lower input limit Upper input limit Units
1 1 64
Multiple of position control-
ler basic clock pulse
Active on
Power On
Active: During position controlled operation (M19)
The number of axes and spindles can be increased by increasing the position control sampling
interval. Such increase will, however, impair the results produced by the controller. See
”Axes” for advantage.
The spindle-specific position controller sampling interval T
LS
is
T
LS
=MD 155 • MD 168 • MD 466*
Notes
• The position control sampling interval must be in an integer ratio to the selected inter-
polation clock pulse (MD 155).
• If a C axis is assigned to the spindle via MD 461*, the position controller clock pulses of
spindle and C axis must coincide. The position controller clock pulse for the C axis is set
in MD 155, MD 160, MD 168, MD 1396*.
Permissible values:
1, 2, 4, 8, 16, 32, 64
Time constant feedforward control 467*
Default value Lower input limit Upper input limit Units
0 0
9 999
1 000 (as from SW 4)
0.1 ms
Active
–
Active: During position controlled operation (M19)
To avoid overshooting on spindles with feedforward control, insert a delay between the partial
setpoint and the position controller. This delay is set with this machine data.
_______
1) The feed forward control can be switched off via PLC MD as from SW 2.
6–78 © Siemens AG 1992 All Rights Reserved 6FC5197- AA50
SINUMERIK 840C (IA)