6 NC Machine Data (NC MD), NC Setting Data (NC SD) 09.95
6.5 Spindle-specific MD (spindle data)
• You can set MD 419* to 426* so that the motor is accelerated to the current limit for a
certain time. If a ramp-up generator is built into the actuator, you can set MD 419* to 426*
to 0. In this case, the setpoint changes in steps on acceleration and deceleration.
• You must set MD 478* to 485* so that the motor can always follow the setpoint without
reaching the current limit. This is especially important in the field weakness area of the
motor.
• When braking in M19 mode, the spindle is first decelerated with the acceleration constant
in MD 419* to 426* to the creep speed set in MD 427* to 434* and then brought to rest in
postion control mode with the acceleration time constant set in MD 478* to 485*.
Creep speed for M19 gear stages 1-8
427*-434*
Default value Lower input limit Upper input limit Units
100 +0 1 500
16 000 (as from SW 4) 1 min1)
Active on
NC Stop
Specifies the speed to which the spindle is to be reduced on an oriented spindle stop (M19)
and at which travel is to continue until positioning on the basis of the specified position control
characteristic (gain factor and acceleration time constant) has been completed (see also
Section Axis (Analog) and Spindle Installation).
Assignments
Gear 1 2 3 4 5 6 7 8
NC MD 427* 428* 429* 430* 431* 432* 433* 434*
The creep speed is the limit beyond which no acceleration takes place:
• When positioning from zero speed, acceleration takes place up to or below the creep
speed.
• When the spindle is running, the position controller becomes active when the creep speed
is reached. The following applies regarding speed control:
– If the momentary speed is less than creep speed, acceleration takes place up to creep
speed. If you do not want this, program S0 before M19.
– If the momentary speed is greater than the creep speed, the spindle speed is reduced
to the creep speed and only then is the position controller activated.
Gain factor for M19 for eight gears
435*-442*
Default value Lower input limit Upper input limit Units
1 666 166 10 000
80 000 (as from SW 5) 0.01 s-1
Active on
NC Stop
Assignments
Gear 1 2 3 4 5 6 7 8
NC MD 435* 436* 437* 438* 439* 440* 441* 442*
_______
1) The input resolution is 0.1 rev/min, if MD 520* bit 3=1.
6–68 © Siemens AG 1992 All Rights Reserved 6FC5197- AA50
SINUMERIK 840C (IA)