YASKAWA Sigma-V Series User Manual page 146

(1) Risk Assessment
When using the HWBB function, be sure to perform a risk assessment of the servo system in advance. Make
sure that the safety level of the standards is met. For details about the standards, refer to Harmonized Stan-
dards at the front of this manual.
Note 1. Applications for certification are pending to show that SERVOPACKs comply with rules and regulations for
North American and other safety standards, including those for safe performance.
2. To meet the performance level d (PLd) in EN ISO 13849-1, the EDM signal must be monitored by a host control-
ler. If the EDM signal is not monitored by a host controller, the system only qualifies for the performance level c
(PLc).
The following risks can be estimated even if the HWBB function is used. These risks must be included in the
risk assessment.
• The servomotor will move in an application where external force is applied to the servomotor (for example,
gravity on the vertical axis). Take measures to secure the servomotor, such as installing a mechanical brake.
• The servomotor may move within the electric angle of 180 degrees in case of the power module failure, etc.
Make sure that safety is ensured even in that situation.
The maximum motor rotation angle is 1/6 of a rotation (This is the converted rotation angle for the motor
shaft).
• The HWBB function does not shut off the main circuit power supply to the SERVOPACK and converter or
electrically isolate them. Take measures to shut off the power to the SERVOPACK and converter before per-
forming maintenance on them.
4.8 Safety Function
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