FANUC Maintenance & Troubleshooting of CNC Robots 2

Question 1

A FANUC robot displays alarm code SRVO-023 (Stop Error Excess). What is the most likely cause?

Accepted Answer

The robot reached a position error exceeding the defined threshold during motion

Answer

SRVO-023 indicates the positional deviation between commanded and actual position exceeded the stop error limit, typically caused by mechanical binding or incorrect gain settings.

Question 2

When replacing a FANUC pulse coder (encoder), which step must be performed immediately after installation?

Accepted Answer

Perform a mastering (zero-point calibration) procedure

Answer

A new pulse coder loses the stored zero-point data, so mastering must be performed to re-establish the robot's reference position.

Question 3

Which FANUC diagnostic screen shows real-time axis torque values useful for detecting mechanical overloads?

Accepted Answer

Status/Servo screen (servo diagnostic monitor)

Answer

The Servo diagnostic monitor (Status > Servo) displays real-time torque percentage, current draw, and positional error for each axis.

Question 4

A FANUC CNC robot exhibits excessive backlash on Joint 2. After ruling out software causes, what mechanical component should be inspected first?

Accepted Answer

The harmonic drive reducer or gearbox

Answer

Excessive backlash on a robot joint is most commonly caused by wear or damage in the harmonic drive reducer or gearbox that transmits motor torque to the link.

Question 5

What does the FANUC controller variable $SCR_GRP[1].$SOFTLMT indicate?

Accepted Answer

The software joint travel limit boundaries for group 1

Answer

$SCR_GRP[1].$SOFTLMT contains the software over-travel limit values that the controller checks against joint angles to prevent exceeding the defined workspace.

(FANUC) Fuji Automatic Numerical Control Robotics Certification Practice Test

(FANUC) Fuji Automatic Numerical Control Robotics Certification Practice Test

FANUC Maintenance & Troubleshooting of CNC Robots 2