F07890 — Internal voltage protection / internal armature short-circuit with STO active

F07890 is raised when the internal armature short-circuit (p1231 = 4) has been requested but cannot be carried out because Safe Torque Off (STO) is enabled. With STO active the pulses cannot be enabled, so the armature short-circuit is not possible and the drive trips: it coasts down and the fault must be acknowledged before it will start. The manuals describe the fault identically for the affected drive objects.

• The internal armature short-circuit is switched in (p1231 = 4) while Safe Torque Off (STO) is enabled; the two states exclude each other, because with STO active the pulses cannot be enabled.

1. Look at p1231: if the internal armature short-circuit is not actually required, switch it out by setting p1231 = 0.
2. If the internal armature short-circuit is required, deactivate Safe Torque Off instead: set p9501 = p9561 = 0.

• p1231 — armature short-circuit / DC braking configuration: set to 4 to switch in the internal armature short-circuit; set to 0 to switch it out and remove the conflict that raises this fault.
• p9501 — SI Motion enable for the safety functions in the Control Unit: one of the two signals that must be set to 0 to deactivate Safe Torque Off.
• p9561 — SI Motion SLS (SG) stop response in the Control Unit: set to 0 together with p9501 to deactivate Safe Torque Off.

The fault must be acknowledged before the drive will restart. Once the cause has been removed — p1231 = 0 to switch out the internal armature short-circuit, or p9501 = p9561 = 0 to deactivate Safe Torque Off — acknowledge the fault on the operator panel or in the commissioning tool; the pulses can then be enabled again and the drive restarted.