12
Functional safety
Integrated Safety Technology
Operating Instructions – MOVIMOT
®
flexible
411
12.2.6
Restrictions
•
Note that if the drive does not have a mechanical brake, or if the brake is defect-
ive, the drive may coast to a halt (depending on the friction and mass moment of
inertia of the system). In the event of regenerative loads, or with axes that are
loaded with gravitational forces or driven externally, the drive can even accelerate.
This must be taken into account in a risk assessment of the system/machine. Addi-
tional safety measures might have to be implemented (e.g. safety brake system).
The drive unit cannot be used without an additional brake system for application-
specific drive safety functions that require active deceleration (braking) of the dan-
gerous movement.
•
When using the SS1(c) (SS1-t) function as described in chapter "Functional
safety" > "Integrated safety technology" > "Drive safety functions", the brake decel-
eration ramp of the drive is not monitored with respect to safety. In the event of a
fault, deceleration may fail during the delay time or, in the worst-case scenario,
there might be an acceleration. In this case, the STO function is only activated
after the set time delay has expired. The resulting danger must be taken into ac-
count in the risk assessment of the system/machine. Additional safety measures
might have to be implemented.
•
The STO function cannot prevent a possible jerk or DC braking.
WARNING
The safety concept is suitable only for performing mechanical work on driven sys-
tem/machine components.
Severe or fatal injuries.
Hazardous voltages are present in the connection box when the STO signal is dis-
connected.
•
Before working on the electric part of the drive system, disconnect it from the
supply voltage using an appropriate external disconnecting device, and secure it
against unintentional reconnection to the voltage supply.
WARNING
Electric shock due to incompletely discharged capacitors.
Severe or fatal injuries.
•
Observe a minimum switch-off time of 5 minutes after disconnecting the power
supply.
INFORMATION
The brake and DynaStop
®
are not safety-related. If the parameter
Apply brake/
DynaStop
®
in STO state (Index 8501.3)
is enabled, the following happens when the
STO function is triggered:
•
The brake is applied.
•
DynaStop
®
is activated.
29128668/EN – 12/2019
