Protection Features - Epson RC700-D Manual

2.3 Protection Features

The robot control system supports protection features described below. However, these
features are prepared for unexpected occurrence.
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.
Motor Overload Detection
The dynamic brake circuit is activated when the system detects the overload status of the
motor.
Irregular Motor Torque (out-of-control Manipulator) Detection
The dynamic brake circuit is activated when irregular motor torque (motor output) is
detected.
Motor Speed Error Detection
The dynamic brake circuit is activated when the system detects that the motor is running at
incorrect speed.
Positioning Overflow –Servo Error- Detection
The dynamic brake circuit is activated when the system detects that the difference between
the Manipulator's actual position and commanded position exceeds the margin of error
allowed.
Speed Overflow –Servo Error- Detection
The dynamic brake circuit is activated when the Manipulator's actual speed is detected to
mark an overflow (the actual speed is outside the nominal range) error.
CPU Irregularity Detection
Irregularity of CPU that controls the motor is detected by the watchdog timer. The system
CPU and the motor controlling CPU inside the Drive Unit are also designed to constantly
check each other for any discrepancies. If a discrepancy is detected, the dynamic brake
circuit is activated.
Memory Check-sum Error Detection
The dynamic brake circuit is activated when a memory check-sum error is detected.
RC700-D Rev.2
Functions 2. Part Names and Functions
77