Tsino Dynatron CoolDrive Series, Руководство пользователя

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Safety features
272
Implementation of STO function 11.3
With the Safety Torque Off (hereinafter referred to as STO) function of CoolDrive Smart7 series servo drives, the drive
signal of the power element inside a servo drive is forced off through the hardware circuit via the safety input signal, thus
turning off the output torque of the motor.
3
4
5
6
7
8
STOM-RET
STOM
STO2
STO2-RET
STO1
STO1-RET
X8
M
Cutoff
PWM
PWM
Cutoff
EDM
Safety function risk assessment 11.4
Be sure to conduct a risk assessment of the device before using the STO safety function to ensure that the device meets the
safety level specified in the standard.
In order to satisfy the PL e in EN ISO 13849-1 and the SIL3 in IEC 61508, the servo parameter 0x21A0 must be set to enable
the self-diagnosis function switch through the servo drive, and the EDM signal must be monitored by the upper computer. If the
above steps are not followed, the results will be PL d and SIL2.
Even with the STO function, the following dangers can still exist.

When this function is used while the servo motor is running, although the power of the servo motor has been cut off, the
motor will continue to rotate for some time due to inertia. Design a safety system to ensure that no danger will occur
before the servo motor stops completely.

When applied in such cases as vertical gravity axis, the motor will move under gravity. To prevent this, set the mechanical
brake system in advance to stop the motor. Note that the servo brake circuit and dynamic brake circuit of the servo drive
and the holding brake of the servo motor are not safety protection measures.

If a fault occurs in the power element of the servo drive and causes a short circuit between the phases of the servo motor,
the servo motor can operate within a maximum electrical angle of 180° and continue to maintain the excitation state. Be
sure to conduct this operation without causing danger.

Before mechanical installation and drive replacement, be sure to carry out the confirmation test of this function. Such
cases as wrong wiring of input and output signals may affect the normal use of this function and lead to danger.

When this function is operating, the input power of the drive is not cut off. Cut off the power supply before maintaining
and checking the drive to prevent electric shock.

The EDM output signal is not a safety output. Do not use for purposes other than fault monitoring.