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4 Commissioning
4.1 Safety Instructions
C A U T I O N
ELECTRICAL HAZARD
The operator or electrical installer is responsible for proper grounding and compliance with all applicable national and local safe-
ty regulations.
and the Operating Guide of the relevant drive. Also, always observe the instructions provided by the
motor manufacturer.
4.2 Activating STO
The STO function is activated by removing the voltage at terminal 37 of the drive. By connecting the drive to external safety devices
providing a safe delay, an installation for a Safe Stop 1 can be obtained. External safety devices must fulfill Cat./PL or SIL when con-
nected to terminal 37. The STO function can be used for asynchronous, synchronous, and permanent magnet motors.
When the STO function (terminal 37) is activated, the drive issues an alarm, trips the unit, and coasts the motor to a stop. Manual
restart is required. Use the STO function to stop the drive in emergency stop situations. In normal operating mode when STO is not
required, use the standard stop function instead. Ensure that requirements according to ISO 12100 paragraph 6.3.3.2.5 are fulfilled
before using the automatic restart function.
4.3 Parameter Settings for STO Used With VLT® PTC Thermistor Card MCB 112
When MCB 112 is connected, more selections are available for
parameter 5-19 Terminal Safe Stop
(options
[4] PTC 1 Alarm
to
[9] PTC 1
& Relay W/A
).
Selections
[1] Safe Stop Alarm
and
[3] Safe Stop Warning
are still available, but for installations without MCB 112 or any external
safety devices. If
[1] Safe Stop Alarm
or
[3] Safe Stop Warning
are selected and MCB 112 is triggered, the drive issues
alarm 72,
Dangerous Failure
and coasts the motor safely without automatic restart.
Do not select
[4] PTC 1 Alarm
and
[5] PTC 1 Warning
when an external safety device is used. Only use those selections when only
MCB 112 uses the STO. If selection
[4] PTC 1 Alarm
or
[5] PTC 1 Warning
is selected and the external safety devices triggers STO,
the drive issues
alarm 72, Dangerous Failure
and coasts the motor safely without automatic restart.
Select
[6] PTC 1 & Relay A
to
[9] PTC 1 & Relay W/A
for combining external safety devices and MCB 112.
C A U T I O N
AUTOMATIC RESTART
Selections allow automatic restart when the external safety device is deactivated. Before selecting
[7] PTC 1 & Relay W
or
[8] PTC 1
& Relay A/W
, ensure that:
The unintended restart prevention is implemented by other parts of the STO installation, or
A presence in the dangerous zone can be physically excluded when STO is not activated. In particular, paragraph 6.3.3.2.5 of
ISO 12100:2010 must be observed.
See VLT® PTC Thermistor Card MCB 112 Operating Guide for further information.
4.4 Automatic/Manual Restart Behavior
The STO default state prevents unintended restarts (restart prevention behavior). To terminate STO and resume normal operation,
follow the procedure below.
Procedure
Reapply 24 V DC to terminal 37.
Give a reset signal via bus, digital I/O, or [Reset] key.
Set the STO function to automatic restart by setting the value of
parameter 5-19 Terminal 37 Safe Stop
from default value
[1] Safe Stop Alarm
to value
[3] Safe Stop Warning
.
Automatic restart means that STO is terminated and normal operation is resumed when the 24 V DC is applied to terminal
37. No reset signal is required.
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Danfoss A/S © 2021.03
Commissioning
Safe Torque Off
Operating Guide