Hardware Manual

Safe Torque off function 229
13
Safe Torque off function
What this chapter contains
This chapter describes the Safe torque off function of the drive and gives instructions
for its use.
Description
The Safe torque off function can be used, for example, to construct safety or
supervision circuits that stop the drive in case of danger (such as an emergency stop
circuit). Another possible application is a prevention of unexpected start-up switch
that enables short-time maintenance operations like cleaning or work on non-
electrical parts of the machinery without switching off the power supply to the drive.
When activated, the Safe torque off function disables the control voltage of the power
semiconductors of the drive output stage (A, see diagram below), thus preventing the
drive from generating the torque required to rotate the motor. If the motor is running
when Safe torque off is activated, it coasts to a stop.
The Safe torque off function has a redundant architecture, that is, both channels must
be used in the safety function implementation. The safety data given in this manual is
calculated for redundant use, and does not apply if both channels are not used.
The Safe torque off function of the drive complies with these standards:
Standard Name
EN 60204-1:2006 + AC:2010 Safety of machinery – Electrical equipment of machines –
Part 1: General requirements