Option description
Contents of this chapter
This chapter describes the Q957, prevention of unexpected start-up, and its settings.
Overview
The Prevention of unexpected start-up (POUS) function disables the control voltage of the
power semiconductors of the drive (inverter) output stage. This prevents the drive from
generating the torque required to rotate the motor. The POUS function activates the Safe
torque off (STO) function of the drive. By using this function, short-time operations (like
cleaning) and/or maintenance work on the non-electrical parts of the machinery can be
performed without switching off and disconnecting the drive.
The user activates the Prevention of unexpected start-up function using a switch mounted
on a control desk. When the switch is open (off), the POUS function is active and the POUS
indicator lamp is on.
The customer is responsible for installing and connecting the operating switch and the
indicator lamp on site. They are not included in the delivery. See the machine-specific C-type
standards whether the indication lamp is required.
For a detailed description of the Safe torque off function, see the appropriate hardware
manual.
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Option description 15
