Description Of Stop C - Siemens SINUMERIK 840D sl Function Manual

Safety functions integrated in the system/drive
7.3 Safe Stops A-F
7.3.4

Description of STOP C

Action in the drive monitoring channel:
The drive is braked along the OFF3 ramp corresponding to the speed setpoint; in parallel, the
timer is started via parameter p9552 "Transition time from STOP C to SBH". The SBH function
is automatically activated after the timer expires.
Action in the NCK monitoring channel:
Essentially the same as the drive, the speed setpoint = 0 is specified by the control, and the
interface signal "Position controller active" (DB31, ... DBX61.5) of the drive involved is set to
zero.
In parallel, the timer is started using MD36952 $MA_SAFE_STOP_SWITCH_TIME_C.
The SBH function is automatically activated after the timer expires.
● Effect:
The drive is braked along the OFF3 ramp under closed-loop speed control and brought into
SBH.
● Alarm message for an internally initiated STOP C:
The alarm message "STOP C triggered" is output (refer to Chapter "NCK safety alarms for
SINUMERIK 840D sl (Page 595)").
● Acknowledgment for an internally initiated STOP C:
An unintentional restart is prevented for a STOP C. The error can be acknowledged using
the NC-RESET key.
SGA "STOP C is active"
This signal indicates that STOP C is active.
0 signal:
1 signal:
It is possible that the stop for the NCK becomes effective one safety monitoring clock cycle
earlier than for the drive. This means that braking along the current limit can become effective
before the OFF3 ramp of the drive becomes effective.
In order to reduce the level of stress of the mechanical system of the machine (if required) the
braking torque can be reduced. To realize this, bit 4 "Torque limiting active in motoring/
regenerating mode" can be set in parameter p1400 and parameter p1521 "Torque limit lower/
regenerative" can be set to the required lower torque. In this case, it should be noted that the
braking distance (stopping distance) of the axis is extended, and that the torque limiting is not
only effective for Stop C, but that generally, the dynamic response of the axis changes.
Alternatively, braking can be realized drive-based along the OFF3 ramp (see Chapter "Braking
response for STOP B/C (Page 123)").
Note
Tracking operation becomes active when a STOP C is initiated.
122
STOP C is not active.
STOP C is active.
Function Manual, 12/2017, 6FC5397-4BP40-6BA1
Safety Integrated