12.2010 Configuration
and Connection Examples
Siemens AG
6SE7087-6QX70 (Version AM)
SIMOVERT MASTERDRIVES
Compendium Motion Control
2-25
2.4.4.2
SS1 principle in a safety function
Fig. 2-10
SS1 principle, two-channel structure
By adding appropriate circuit components, the SS1 safety function can
be implemented on the basis of the STO function. In this case as well,
the function architecture is essentially two-channel.
The subsystem ACQUIRE can have the same structure as described in
subsection 2.4.4.1 "STO principle in a safety function".
A safety-oriented dropout delay must be added to the subsystem
EVALUATE.
Activation of the safety function by the subsystem ACQUIRE initiates
an instantaneous, single-channel quick stop on the drive. A safe timer
is started simultaneously in EVALUATE.
The dropout delay of the timer must be set such that the drive can
decelerate down to zero speed along the quick stop ramp before the
timer runs down. On timeout, the drive is safely switched to a no-torque
condition in accordance with subsection 2.4.4.1 "STO principle in a
safety function".
