Siemens SINUMERIK 840D sl Function Manual page 578

Interaction with Other Functions
11.1 Limiting the speed setpoint
S For the changeover via SGEs, the states from both monitoring channels are
taken into consideration to take into account differences in the times. This re-
sults in the following rules:
1. Changing–over from non–safe operation in SG/SBH
There is no delay (VELO_SWITCH_DELAY), so that this changeover must
always be performed at zero speed or below the enabled SG limit.
2. Changing–over from SGx to SGy
A) SGx > SGy (braking): A lower setpoint is entered as soon as changeover
is detected in one of the two channels.
B) SGx < SGy (acceleration): A higher setpoint is only entered if both chan-
nels have changed–over.
3. Changing–over from SG to SBH (braking)
A lower setpoint (= 0) is entered as soon as the changeover has been de-
tected in one of the two channels.
4. Changing–over from SBH to SG (accelerating)
A higher setpoint is only entered if both channels have changed–over.
5. Changing–over from SBH/SG into non–safe operation (accelerating)
A higher setpoint is only entered if both channels have changed–over.
S Effect of the function in the NCK interpolator:
– Setpoint limiting is active in both the AUTO as well as in the JOG modes.
– When changing–over while moving to higher safely reduced speeds, the
position control loop should be set so that it does not overshoot. This means
that a sudden setpoint limit change does not cause the monitoring to re-
spond on the actual value side.
– When transformation is active, safety setpoint limits, axially effective in the
interpolator are reduced by the transformation itself depending on the actual
position.
Note
There are no restrictions for motion from synchronous actions.
11-578
SINUMERIK 840D sl/SINAMICS S120 SINUMERIK Safety Integrated (FBSI sl) – 05.2008 Edition
© Siemens AG 2008 All Rights Reserved
05.08