Siemens SINUMERIK 840C - Manual (Page 997)

12 Functional Descriptions 10.94
12.20.7 Retraction
12.20.7 Retraction
The retraction motion can be parameterized and programmed.
The following diagram shows the possible sources and the associated reactions for the
extended, parameterizable and open-loop controlled retraction without giving the programmable
retraction motions.
Programmable retraction as open-loop control function
NC MD
528* 588*
Generator minimum
speed limit
DC link warning threshold
Emergency retraction
threshold FA
EMERGENCY
STOP
Channel-specific/
general sources External sources
HW input
(1 byte per mode group)
1 MD byte
for enabling
per axis/spindle 1 MD byte
for enabling
per channel
0: Signal not operative
1: Signal operative
• Mixed I/O
• CSB
Channel-specific
interface DB 10-DB 15
Axis/spindle-
specific sources
1 MD byte
for enabling
per channel
1 MD byte
for enabling
per axis/spindle
and channel 1 MD byte
per axis/spindle
and channel
HW output
One byte per mode group Retraction signal
DB 29 - DB 31 0: Reaction is not initiated
1: Reaction is initiated
e.g.: Mode group stop
e.g.: Alarm
e.g.: Internal retraction
Axis/spindle-
specific interface
NC MD 922*
NC MD 916*
NC MD 530* 596*
NC MD 918* NC MD 529* 592*
NC MD 920*
Mode group stop
There are two categories of retraction, i.e.
• as an open-loop control function and
• as an autonomous drive function.
Sources
There are four source areas for the retraction process:
• Internal axis/spindle-specific sources,
• Internal sources specific to channel/mode group or general sources,
• External sources via HW inputs,
• Communications failure (autonomous drive sources which initiate generator-mode braking
of the drive).
12–222 © Siemens AG 1992 All Rights Reserved 6FC5197- AA50
SINUMERIK 840C (IA)