58
Unidrive M400 User Guide
Issue Number: 2
In the event that the two-channel operation is not required, the two
inputs can be connected together to form a single SAFE TORQUE OFF
input. In this case it is important to note that a single short-circuit from
the SAFE TORQUE OFF input to a DC supply of approxi24 V
would cause the drive to be enabled. This might occur through a fault in
the wiring. This can be excluded according to EN ISO 13849-2 by the
use of protected wiring. The wiring can be protected by either of the
following methods:
•
By placing the wiring in a segregated cable duct or other enclosure.
or
•
By providing the wiring with a grounded shield in a positive-logic
grounded control circuit. The shield is provided to avoid a hazard
from an electrical fault. It may be grounded by any convenient
method; no special EMC precautions are required.
SAFE TORQUE OFF over-ride
The drive does not provide any facility to over-ride the SAFE TORQUE
OFF function, for example for maintenance purposes. Because of the
risk of human error, the installation must not provide any facility to
override the function. The design of safety-related control systems must
only be done by personnel with the required training and experience.
The SAFE TORQUE OFF function will only ensure the safety of a
machine if it is correctly incorporated into a complete safety system. The
system must be subject to a risk assessment to confirm that the residual
risk of an unsafe event is at an acceptable level for the application.
SAFE TORQUE OFF does not provide electrical isolation. The supply to
the drive must be disconnected by an approved isolation device before
gaining access to power connections.
With SAFE TORQUE OFF there are no single faults in the drive which
can permit the motor to be driven. Therefore it is not necessary to have a
second channel to interrupt the power connection, nor a fault detection
circuit. It is essential to observe the maximum permitted voltage of 5 V
for a safe low (disabled) state of SAFE TORQUE OFF.
The connections to the drive must be arranged so that voltage drops in
the 0 V wiring cannot exceed this value under any loading condition. It is
strongly recommended that the SAFE TORQUE OFF circuits be
provided with a dedicated 0 V conductors which should be connected to
terminals 32 and 33 at the drive.
For more information regarding the SAFE TORQUE OFF input, please
see the Control Techniques Safe Torque Off Engineering Guide
available for download from www.controltechniques.com.
For more information regarding the SAFE TORQUE OFF input, please
see the
Control Techniques Safe Torque Off Engineering Guide
available for download from www.controltechniques.com.
The design of safety-related control systems must only be
done by personnel with the required training and experience.
The SAFE TORQUE OFF function will only ensure the safety
of a machine if it is correctly incorporated into a complete
safety system. The system must be subject to a risk
assessment to confirm that the residual risk of an unsafe
event is at an acceptable level for the application
SAFE TORQUE OFF does not provide electrical isolation.
The supply to the drive must be disconnected by an
approved isolation device before gaining access to power
connections.
It is essential to observe the maximum permitted voltage of 5
V for a safe low (disabled) state of SAFE TORQUE OFF.
The connections to the drive must be arranged so that
voltage drops in the 0 V wiring cannot exceed this value
under any loading condition. It is strongly recommended that
the SAFE TORQUE OFF circuits be provided with a
dedicated 0 V conductors which should be connected to
terminals 32 and 33 at the drive.
WARNING
WARNING
WARNING
Summary of Contents for Unidrive M400
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