SE-Power FS STO-manual vers. 1.6 en.12.08.2015
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The power supply to the drive is reliably disconnected via the active safety function STO
“Safe Torque Off”. The drive cannot generate torque and so cannot perform any hazardous
movements. With suspended loads or other external forces, additional measures must be
taken to reliably prevent sagging (e.g. mechanical holding brake). In the STO “Safe Torque
Off” state, the standstill position is not monitored.
The machine must be stopped in a safe manner, e.g. via a safety switching device. This
applies specifically to vertical axes without self-locking mechanism, clamping unit or
counterbalance.
Note
There is a risk that the drive will advance in case of multiple errors in the SE-Power
FS.
If the output stage of the servo drive fails while in the STO status (simultaneous
short circuit of 2 power semiconductors in different phases), a limited dwell
movement of the rotor may result. The rotation angle / path correspond to a pole
pitch. Examples:
Rotary axis, synchronous machine, 8-pin
movement < 45° at the motor shaft
.
Linear motor, poles pitch 20 mm
movement < 20 mm at the moving part.
4.2.2
Overview of interface [X40]
On its front, the safety module provides an 8-pin connection [X40] for control ports, feedback
contact and a 24 V auxiliary supply for external sensors
Section 5.2
The safety function STO is requested solely via the two digital control ports STO-A and STO-
B. A safety circuit for additional interfaces at the SE-Power servo drive is neither required nor
intended
Cross-circuit detection in the input circuit is not carried out by the safety module.
The status of the servo drive is reported back to an external safety switching device through
a potential-free acknowledgment contact (normally open). This enables downwards-
compatible activation in a mixed configuration, comprising an SE-Power (previous series with
the “Safe Stop” function to be realised via the connection [X3]) and the SE-Power FS
Section 8.3
The interface [X40] permits the direct connection of active and passive sensors, since a 24 V
supply voltage (auxiliary supply) with corresponding reference potential is lead out.
