Siemens SINUMERIK 840D sl Function Manual page 128

Safety Functions Integrated in the System/Drive
6.3 Safe stops A-F
Note
A delay time between STOP F and STOP B should only be set, if, during this time,
an alternative response is initiated by evaluating the system variables
$VA_XFAULTSI and $A_XFAULTSI.
Further, when using the delay time, a monitoring function should always be active
– also in the automatic mode (e.g. SE, SN, SG with high limit switch). For
example, if the SBH monitoring function is only active on the drive side, for
example because of the (single-channel) failure of a door switch, then although
this results in a STOP F, the STOP F –> STOP B delay time on the NCK side is
not started if previously no monitoring function was active. This means that in this
case, the drive responds with a STOP B (however this is also initiated in the NCK
due to the exchange of the stop responses), but this is not displayed in the NCK
variables $VA_XFAULTSI and $A_XFAULTSI.
The appropriate monitoring functions of the drive (e.g. when SBH is selected) are
also executed instantaneously without any delay.
Example 1 – delaying the transition from STOP F to STOP B:
The speed characteristics of an axis for parameterized stopping are shown in
Fig. 6-7. In this case, the axis should continue 500 ms and then brake along the
parameterized ramp. A delay time of 2.5 s is selected until STOP B is initiated
($MA_SAFE_STOP_SWITCH_TIME_F).
v
Fig. 6-7
The following actions take place at the following instants in time:
t1:
STOP F occurs, ESR is started
t2:
500 ms after t1, braking starts along the parameterized ramp
t3:
STOP B is initiated 2.5 s after t1. The axis is already stationary at this time, which
means that the pulses can be immediately cancelled.
6-128
SINUMERIK 840D sl/SINAMICS S120 SINUMERIK Safety Integrated (FBSI sl) – 03.2006 Edition
Continue to traverse (ESR)
t2
t1
Velocity characteristic of an SI axis when stopping with STOP F
Braking along a ramp =
stopping (ESR)
t3
© Siemens AG, 2006. All rights reserved
03.06
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