Term/abbreviation
Explanation
STA
Feedback, STO active
t
STA,Out
Max. delay for diagnostic feedback (≤ permissible reaction time when a
safety function is requested
1)
+ 10 ms)
n
Rotational speed
1) see Technical data, STO safety data
Tab. 3 Legend for STO timing
4.1.3
Safety function SBC
Fig. 5 Symbol SBC
The function described here implements the SBC safety function according to EN 61800-5-2.
The SBC safety function is used for controlling a holding brake in the motor and a clamping unit or
brake on the axle to slow an axle down mechanically or stop it safely.
SBC function and application
The SBC safety function provides safe output signals for the control of brakes (holding brakes or
clamping units). Brakes are controlled over 2-channels by switching off the voltage at the following
outputs:
–
Safe output BR+/BR– [X6B] for the holding brake of the motor
–
Safe output BR-EXT/GND [X1C] for the external brake/ clamping unit
The holding brake and/or clamping unit engage and slow the motor or axle. Dangerous movements
should thus be braked mechanically. The braking time is dependent on how quickly the brake engages
and how high the energy level is in the system.
The use of
only one brake
is possible
è
Tab. 16 Safety reference data of the SBC safety functiononly
in case of low performance requirements. To do this, connect the brake either to BR+/BR–
or
to BR-
EXT.
NOTICE!
If there are suspended loads, they usually drop if SBC is requested simultaneously with STO. This can
be traced back to the mechanical inertia of the holding brake or clamping unit and is thus unavoid-
able. Check whether the SS1 safety function is better suited.
SBC may only be used for holding brakes or clamping units which engage in the de-energised state.
Ensure the lines are installed in a protected manner.
Functional principle SBC
Product overview
11
Festo — CMMT-AS-...-S1 — 2018-02