The safety technology checks the selection signals for validity. In the case of
dual-channel wiring and single-channel selection, the second channel also
has to be selected before deselection. Otherwise, an error message is
generated (F8301).
The tolerance time for different selection between the two
selection channels is 1 s. The parameter setting of the tolerance
time cannot be changed.
For diagnostic purposes, the state of the safety function "Safe Torque Off"
may be read via a parameter (P‑0‑0106).
Notes on commissioning
For examples of interconnection, please refer to "
Notes on project planning
When configuring the safety function "Safe Torque Off", it is absolutely
necessary to observe the following safety instructions:
Lethal injury and/or property damage caused
by unintended axis motion!
DANGER
⇒ If external force influences are to be expected with the safety function
"Safe Torque Off", e.g. in the case of a vertical axis, this motion has to be
safely prevented by additional measures, e.g. a mechanical brake or a
counterweight. For such axes, Bosch Rexroth recommends using the Safe
braking and holding system.
Injury and/or property damage caused by
deviation from standstill position!
WARNING
⇒ Even if power section control has been safely locked, momentary axis
motion, depending on the number of poles of the motor, can be triggered,
when two errors are occurring simultaneously in the power section with the
voltage DC bus being active:
●
breakdown of a power semiconductor and
●
breakdown of another semiconductor
In this case, two of six semiconductors are affected in such a way that the
motor shaft is aligning.
Synchronous motor, for example: In the case of a synchronous motor with 6
pole pairs, the motion can be a maximum of 30 degrees. For a directly driven
ball screw, e.g. 20 mm per revolution, this corresponds to a one-time
maximum linear motion of 1.67 mm.
When an asynchronous motor is used, the short circuits in two separate
circuits of the power section have almost no effect, because the exciter field
breaks down when the inverter is shut down and has completely died down
after approx. 1 s.
30/65
Integrated safety function
ctrlX SAFETY "Safe Torque Off" Safety Option in ctrlX DRIVE
Bosch Rexroth AG R911383774_Edition 03
