Risk Assessment - YASKAWA SGD7S Product Manual

11.2 Hard Wire Base Block (HWBB)

11.2.1 Risk Assessment

11.2.1 Risk Assessment

When using the HWBB, you must perform a risk assessment of the servo system in advance to
confirm that the safety level of the standards is satisfied. Refer to the following section for
details on the standards.
Compliance with UL Standards, EU Directives, and Other Safety Standards on page xxiii
Note: To meet performance level e (PLe) in EN ISO 13849-1 and SIL3 in IEC 61508, the EDM1 signal must be mon-
itored by the host controller. If the EDM1 signal is not monitored by the host controller, the level will be safety
performance level c (PLc) and SIL1.
The following hazards exist even when the HWBB is operating. These hazards must be
included in the risk assessment.
• The Servomotor will move if an external force is applied to it (for example, gravity on a vertical
axis). Implement measures to hold the Servomotor, such as installing a separate mechanical
brake.
• If a failure occurs such as a Power Module failure, the Servomotor may move within an elec-
tric angle of 180°. Ensure safety even if the Servomotor moves.
The rotational angle or travel distance depends on the type of Servomotor as follows:
• Rotary Servomotor: 1/6 rotation max. (rotational angle calculated at the motor shaft)
• Direct Drive Servomotor: 1/20 rotation max. (rotational angle calculated at the motor shaft)
• Linear Servomotor: 50 mm max.
• The HWBB does not shut OFF the power to the SERVOPACK or electrically isolate it. Imple-
ment measures to shut OFF the power supply to the SERVOPACK before you perform main-
tenance on it.
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