Safe Torque Off (Sto) - Kollmorgen SERVOSTAR 300 Serie Manuel

S300 Product Safety Guide | 2 English

2.4.9 Safe Torque Off (STO)

The safety circuit implementation used for the safety function "Safe Torque Off" in the drive
is suited for SIL 2 according to IEC 62061 and PLd / Cat.3 according to ISO 13849-1.
An additional digital input (STO) releases the power output stage of the drive as long as a 24
V signal is applied to this input. If the STO input goes open-circuit, then power will no longer
be supplied to the motor, and the drive will lose all torque and coast to a stop.
2.4.9.1 Safety instructions
Serious injury could result when a suspended load is not properly blocked. The servo amp-
lifier cannot hold a vertical load when STO is active.
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,
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. This can be used to pre-
vent a faulty output from unintentionally activating the safety function STO. Since the restart
lock is a single-channel system, erroneous engaging will not be recognized.
When STO is engaged during operation by separating input STO-Enable from 24VDC, the
motor runs down out of control and the servo amplifier displays the error F27. There is no
possibility of braking the drive controlled. Risk from uncontrolled movement! If a controlled
braking before the use of STO is necessary, the drive must be braked and the input STO-
ENABLE has to be separated from +24 VDC time-delayed.
When wiring the STO input within one enclosure it must be paid attention to the fact that the
used cables and the enclosure meet the requirements of IEC 60204-1. If the wiring leads out-
side the demanded enclosure, the cables must be laid durably (firmly), and protected from
outside damage.
Keep to the following functional sequence when the restart lock STO is used :
1. Brake the drive in a controlled manner (speed setpoint = 0V)
2. When speed = 0 rpm, disable the servo amplifier (enable = 0V)
3. If there is a suspended load, block the drive mechanically
4. Activate STO
If the STO function is not needed in the application, then the input STO-ENABLE must be
connected directly with +24VDC. The STO function is passed by now and cannot be used.
The servo amplifier cannot be used as a safety component referring to the EC Machine Dir-
ective now.
50 Kollmorgen | kdn.kollmorgen.com | November 2018
WARNING
No Brake Power!
Add a safe mechanical blocking (for instance, a motor-holding brake).
CAUTION
High electrical voltage!
disconnected the servo amplifier from mains supply,
consider the discharging time of the DC-Bus link.