AKD-C Installation | 7 Technical description and data
7.15 Global Safe Torque Off (STO)
7.15.1 STO Safety instructions
WARNING
No Brake Power
Serious injury could result when a suspended load is not properly
blocked. The drive cannot hold a vertical load when STO is active.
Add a safe mechanical blocking (for instance, a motor-holding brake).
The drives have not to be used for driving elevators.
WARNING
Automatic Restart
Risk of death or serious injury for humans working in the machine. The
drive might restart automatically after power on, voltage dip or interruption
of the supply voltage, depending on the parameter setting. If parameter
DRV.ENDEFAULT for one AKD-N is set to 1,
then place a warning sign ("WARNING: Possible Automatic Restart" or
similar) to the machine.
Ensure, that power on is not possible, while humans are in a dan-
gerous zone of the machine.
In case of using an undervoltage protection device, you must observe
EN 60204-1:2006 chapter 7.5 .
CAUTION
High electrical voltage
Risk of electrical shock! The STO function does not provide an electrical
separation from the power output. If access to the motor power terminals is
necessary,
disconnected the drive from mains supply,
consider the discharging time of the DC-Bus link.
If the safety function STO is automatically activated by a control system, then make sure
that the output of the control is monitored for possible malfunction. The monitoring can be
used to prevent a faulty output from unintentionally activating the STO function.
It is not possible to perform a controlled brake if the drive controlled STO-Enable is off. If con-
trolled braking before the use of the STO function is necessary, the drive must be braked and
the input STO must be separated time-delayed from +24 V .
In case of a specific double fault within a very short time (see (
# 39) a single movement of
a maximum angle of 120° (electrical) can happen. This effect can only happen if the drive is
in the function STO. Even if the STO function will be issued for a whole year, this event will
only happen every 100 Billion years.
The STO Status signals are informal and not relevant for functional safety.
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Kollmorgen | kdn.kollmorgen.com | February 2018
