Retraction; Sources - Siemens SINUMERIK 840C Installation Instructions Manual

12 Functional Descriptions

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.
Axis/spindle-
specific sources
DC link warning threshold
Generator minimum
Emergency retraction
speed limit
NC MD 530* 596*
1 MD byte
for enabling
per axis/spindle
0: Signal not operative
1: Signal operative
Axis/spindle-
specific interface
Retraction signal
DB 29 - DB 31
Programmable retraction as open-loop control function
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
Channel-specific/
general sources
Mode group stop
EMERGENCY
STOP
threshold FA
NC MD 920*
1 MD byte 1 MD byte
for enabling for enabling
per channel per channel
NC MD 918*
NC MD 529* 592*
1 MD byte 1 MD byte
for enabling per axis/spindle
per axis/spindle and channel
and channel
0: Reaction is not initiated
1: Reaction is initiated
e.g.: Mode group stop
e.g.: Alarm
e.g.: Internal retraction
© Siemens AG 1992 All Rights Reserved
External sources
HW input
(1 byte per mode group)
NC MD 922*
• Mixed I/O
• CSB
NC MD 916*
NC MD
528* 588*
Channel-specific
interface DB 10-DB 15
HW output
One byte per mode group
6FC5197- AA50
SINUMERIK 840C (IA)
10.94