Festo CMMD-AS series, Руководство по установке

Страница: 80 / 131

4. Functional safety engineering
80 Festo P.BE-CMMD-AS-HW-EN 1002NH
4.2 Integrated function "Safe Torque Off" (STO)
Warning
The general safety functions do not provide protection from electric
shock but only from dangerous movements!
4.2.1 General remarks/description "Safe Torque Off" (STO)
With the STO function, the power supply to the motor is securely interrupted through
switching off of the end stage enable and of the power supply to the output stage. The
drive cannot generate torque or any force and so cannot make any dangerous movements.
If the STO function is activated with a moving drive, the motor starts to run out in an
uncontrolled manner after at most 3.2 ms. At the same time, the automatic brake control
is activated.
If you use motors with a holding brake, each STO disconnection places wear and tear on
the brake. Therefore, use motors without holding brakes for the STO function.
Application examples for the STO function:
- Manual manipulation during set-up
- Manual manipulation during changeover
- Eliminating malfunctions.
The use of the integrated solution offers several advantages:
Advantages - Fewer external components, e.g. fuses
- Less cabling effort and less space required in the control
cabinet
- Lower costs.
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 significant
waiting time when the system is restarted.
Warning
For use of the STO function in the CMMD-AS, both plug connectors
[X3.1] and [X3.2] must always be connected in a manner conforming
to the documentation. If only one plug connector [X3.1] or [X3.2] is
wired, when the STO is demanded, only the corresponding power
output stage is securely switched off (as depicted in chapter 4.2.3
"Switching example STO").