Safety Features - Epson RC620 CU Manual

Setup & Operation 2. Part Names and Functions

2.4 Safety Features

The robot control system supports safety features described below. However, the user is
recommended to strictly follow the proper usage of the robot system by thoroughly reading
the attached manuals before using the system. Failure to read and understand the proper
usage of the safety functions is highly dangerous.
Among the following safety features, the Emergency Stop Switch and Safety Door Input are
particularly important. Make sure that these and other features function properly before
operating the robot system.
For details, refer to the Setup & Operation 8. EMERGENCY.
Emergency Stop Switch
The EMERGENCY connector on the Controller has expansion Emergency Stop input
terminals used for connecting the Emergency Stop switches.
Pressing any Emergency Stop switch can shut off the motor power immediately and the robot
system will enter the Emergency Stop condition.
Safety Door Input
In order to activate this feature, make sure that the Safety Door Input switch is connected to
the EMERGENCY connector at the Controller.
When the safety door is opened, normally the Manipulator immediately stops the current
operation, and the status of Manipulator power is operation-prohibited until the safety door is
closed and the latched condition is released. In order to execute the Manipulator operation
while the safety door is open, you must change the mode selector key switch on the Teach
Pendant to the "Teach" mode. Manipulator operation is available only when the enable
switch is on. In this case, the Manipulator is operated in low power mode.
Low Power Mode
The motor power is reduced in this mode.
Executing a power status change instruction will change to the restricted (low power) status
regardless of conditions of the safety door or operation mode. The restricted (low power)
status ensures the safety of the operator and reduces the possibility of peripheral equipment
destruction or damage caused by careless operation.
Dynamic Brake
The dynamic brake circuit includes relays that short the motor armatures. The dynamic
brake circuit is activated when there is an Emergency Stop input or when any of the
following errors is detected: encoder cable disconnection, motor overload, irregular motor
torque, motor speed error, servo error (positioning or speed overflow), irregular CPU,
memory check-sum error and overheat condition inside the Motor Driver Module.
Encoder Cable Disconnection Error Detection
The dynamic brake circuit is activated when the Motor Encoder Signal cable is disconnected.
Motor Overload Detection
The dynamic brake circuit is activated when the system detects that the load on the motor has
exceeded its capacity.
Irregular Motor Torque (out-of-control manipulator) Detection
The dynamic brake circuit is activated when irregularity with motor torque (motor output) is
detected (in which case the Manipulator is out of control).
22 RC620 Rev.8