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GD1 – Installation Guide
2.1- DESCRIPTION
Safe Torque Off (STO) definition according to the EN 61800-5-2 standard:
"Power, that can cause rotation (or motion in the case of a linear motor), is not applied to the motor. The drive will
not provide energy to the motor which can generate torque (or force in the case of a linear motor)'.
The STO function corresponds to an uncontrolled stopping in accordance with the stop category 0 of the EN
60204-1 standard.
The STO function may be used where power removal is required to prevent an unexpected start-up.
In circumstances where external influences (with vertical loads for example) are present, additional measures
(mechanical brakes for example) may be necessary to prevent any hazard.
The standard output of the drive must not be considered as a safe output. When using a mechanical brake, it will
be mandatory to introduce a safe contact from an external device in the brake actuation line.
The STO function cannot be considered as a safe insulation device for the motor. It does not prevent from any
voltage on the motor terminal block.
STO_OUT+
STO_OUT-
K1
STO1
External
GND
STO2
External
GND
2.2– RECOMMENDATIONS FOR THE INTEGRATION
2.2.1 – SAFETY INSTRUCTIONS
The integration of the STO function must be the result of a risk analysis of the complete machine. All control
components must comply with the requirements of this risk analysis.
Installing and commissioning of safety functions must be performed by skilled personnel only.
Short-circuit avoidance:
Install the drive in a control cabinet with a minimum IP54 protection.
Avoid control signals proximity. Any short-circuit between two control signals must be detected:
- the short circuit will either be detected by the circuit breaking system (fuse for example); in this case, the voltage
reference is grounded, and shielded pair cables must be used (shield is connected to the ground), or a ribbon
cable with all unused wires connected to the ground to prevent proximity with high potential signals,
- or a short-circuit detection device must be integrated.
Take care that, as the STO function performs the motor power removal without shutting down the power supply,
electrical risks remain unchanged when the STO function is active or inactive.
In case of applications with vertical axes, additional measures (mechanical brake) may be necessary.
Refer to the EN13849-2 standard for any complementary information.
Part 3 - Appendix
2 – "SAFE TORQUE OFF" OPTION
k1-1
µC
Enable
PWM
DSP
Functional block diagram
+15V
k1-2
IGBT Module
Vcc
Vcc
M
53
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