Siemens SINUMERIK 840C Installation Instructions Manual page 337

6 NC Machine Data (NC MD), NC Setting Data (NC SD)
6.6.4 Axis-specific MD bits 1 (axial bits 1)
NC MD 7
Switch over Switch over
output bit 7 output bit 6
588*
on on
emergency emergency
retraction retraction
These bits only affect following axes and are active immediately
Bit 0-7 Switchover bit for emergency retraction
Bit 0-7 = 1 The corresponding bit in the output byte of the mixed I/O module only switches
from rest to the inverse condition when an emergency retraction has been
triggered by this axis.
Bit 0-7 = 0 The corresponding bit in the output byte of the mixed I/O module remains
unchanged with an emergency retraction.
Active: At once
Comments:
The state of rest (i.e. the condition after Power on, Reset) is 1 for all the bits of mixed I/O
module.
If an axis/spindle triggers an emergency retraction, the bits defined in MD 588*, 528* change
from 1 to 0.
Even if several axes trigger an emergency retraction simultaneously or in quick succession and
the same bit is marked for all of them, it only changes from rest to error condition once. This is
then maintained until the next Reset.
Example:
12 is set in MD 312
This means that for the first mode group the 2nd byte of the 1st mixed I/O module is used for
the emergency stop. After Reset all outputs of this byte are set to 1.
X (1st axis) and Y (2nd axis) are defined as following axes.
0001 0001 is set in MD 5880 and 001 0010 is set in MD 5881.
If the X axis detects that the emergency retraction threshold has been exceeded in follow-up
mode and emergency retraction has been enabled via PLC interface signal, bit 0 and bit 4 in
the mixed I/O module change from 1 to 0.
If the Y axis then detects an emergency retraction, bit 1 additionally toggles to 0. Bit 4 is
already at 0 and remains so.
With these switchover bits it is possible to output common signals for several axes of one
mode group as well as axis-specific signals.
6–152
Bit No.
6 5 4
Switch over Switch over
output bit 5 output bit 4
on on
emergency emergency
retraction retraction
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Siemens AG 1992 All Rights Reserved
3 2 1
Switch over Switch over Switch over
output bit 3 output bit 2 output bit 1
on on on
emergency emergency emergency
retraction retraction retraction
SINUMERIK 840C (IA)
09.95
0
Switch over
output bit 0
on
emergency
retraction
6FC5197- AA50