Festo CMMP-AS-C2-3A, Mounting And Installation Manual, Page: 48 / 110

5. Functional safety engineering
48 Festo P.BE-CMMP-AS-3A-HW-EN 0708NH
Stop category Type Handling
0 Uncontrolled shutdown through imme-
diate switching off of the energy.
EMERGENCY-OFF or EMERGENCY-STOP
1 Controlled shutdown through switching
off of the energy when a standstill has
been reached.
EMERGENCY-STOP
2 Controlled standstill without switching
off of the energy.
Not suitable for EMERGENCY-OFF or
EMERGENCY-STOP
Table 5.3 Stop categories
5.2 Integrated "Safe standstill" function
Warning
The "Safe standstill" function does not provide protection against
electric shock but rather only against dangerous mechanical motion!
5.2.1 General information / description of "Safe standstill"
With "Safe standstill" the energy supply to the device is reliable interrupted. The drive
may not generate torque and thus cannot make any dangerous rotations. With suspended
loads, additional measures must be taken to ensure that the load does not fall (e.g. me-
chanical holding brake). Monitoring of the standstill position must not be performed in the
"Safe standstill" state.
There are 3 suitable measures for implementing "Safe standstill":
Measures - Circuit breaker between the mains grid and the drive system
(mains breaker)
- Circuit breaker between the power unit and the drive motor
(motor breaker)
- Secure pulse blocker (blocking of impulses to the power semi-
conductors, integrated into the CMMP-AS)
The use of the integrated solution (secure pulse blocker) offers several advantages:
Advantages - Fewer external components, e.g. circuit breakers
- Less cabling effort and less space required in the switching
cabinet
- Lower cost
Another advantage is the availability of the system. The integrated solution allows the
intermediate circuit of the servo controller to remain charged. This means no waiting time
when the system is restarted.