Siemens SINUMERIK 840C - Manual (Page 824)

10.94 12 Functional Descriptions
12.7.2 Description of the spindle modes
Aborting the positioning mode
The specified position is regarded as having been reached (or the distance as having been
traversed) when the spindle is within the position window. This is signalled to the PLC by
setting IS:SPINDLE POSITION REACHED.
The position is held under position control until the M19 function is aborted. The conditions for
aborting are as follows:
• IS ACKNOWLEDGE M19
• M3/M4 in part program or command channel
• Select C axis or synchronous mode
• Program end
• Reset
Abort behaviour can be influenced by MD bits (see section headed "Switching logic").
Setting IS:SPINDLE DISABLE or resetting IS:SERVO ENABLE interrupts the positioning mode.
If the signal is reset again or set again, positioning is continued, but with the following
exception:
• If the positioning mode was selected from the command channel, it will be interrupted if
IS:SERVO ENABLE is reset. An error message will be entered in the user interface.
Positioning will not be continued, however, if the signal is set again.
Curved acceleration characteristic (SW 4 and higher)
When induction motors are used (spindle operation), allowance must be made for their speed-
dependent acceleration capability in position-controlled operation:
Fig. 1 Torque characteristic of induction motor
TorqueM
Constant
torque
Breakdown limit
M = const
Constant
power
M 1/n M 1/(n*n)
Rated speed Speed n
n
n
n
k
n
max
© Siemens AG 1992 All Rights Reserved 6FC5197- AA50 12–49
SINUMERIK 840C (IA)