External Device Monitor (Edm1) - YASKAWA Sigma-V Series User Manual

(9) Brake Signal (/BK)
When the /HWBB1 or /HWBB2 signal is OFF and the HWBB function operates, the brake signal (/BK) will
turn OFF. At that time, Pn506 (brake reference - servo OFF delay time) will be disabled. Therefore, the servo-
motor may be moved by external force until the actual brake becomes effective after the brake signal (/BK)
turns OFF.
• The brake signal is not a safety-related part of a control system. Be sure to design the system so that the
system will not be put into danger if the brake signal fails in the HWBB state. Moreover, if a servomotor
with a brake is used, keep in mind that the brake for the servomotor is used only to prevent the movable
part from being moved by gravity or an external force and it cannot be used to brake the servomotor.
(10) Dynamic Brake
If the dynamic brake is enabled in Pn001.0 (Stopping Method for Servomotor after SV_OFF Command is
Received), the servomotor will come to a stop under the control of the dynamic brake when the HWBB func-
tion works while the /HWBB1 or /HWBB2 signal is OFF.
• The dynamic brake is not a safety-related part of a control system. Be sure to design the system so that
the system will not be put into danger if the servomotor coasts to a stop in the HWBB state. Usually, use a
sequence in which the HWBB state occurs after the servomotor is stopped using the reference.
• If the application frequently uses the HWBB function, do not use the dynamic brake to stop the servomo-
tor. Otherwise element deterioration in the SERVOPACK and converter may result. To prevent internal ele-
ments from deteriorating, use a sequence in which the HWBB state occurs after the servomotor has come
to a stop.
(11) Servo Alarm Output Signal (ALM)
In the HWBB state, the servo alarm output signal (ALM) is not sent.

4.8.2 External Device Monitor (EDM1)

The external device monitor (EDM1) functions to monitor failures in the HWBB function. Connect the moni-
tor to feedback signals to the safety function device.
Note: To meet the performance level d (PLd) in EN ISO13849-1, the EDM signal must be monitored by a host controller.
If the EDM signal is not monitored by a host controller, the system only qualifies for the performance level c (PLc).
 Failure Detection Signal for EDM1 Signal
The relation of the EDM1, /HWBB1, and /HWBB2 signals is shown below.
Detection of failures in the EDM1 circuit can be checked using the following four status of the EDM1 signal
in the table. Failures can be detected if the failure status can be confirmed, e.g., when the control power supply
is turned ON.
Signal
Name
/HWBB1 ON
/HWBB2 ON
EDM1 OFF
• The EDM1 signal is not a safety output. Use it only for monitoring a failure.
CAUTION
CAUTION
Logic
ON OFF
OFF ON
OFF OFF
WARNING
OFF
OFF
ON
4.8 Safety Function
4
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