FANUC Maintenance & Troubleshooting of CNC Robots 3

Question 1

Alarm SRVO-047 (HVAL Alarm) appears on a FANUC robot. What does this indicate?

Accepted Answer

Hardware velocity exceeded the axis speed limit

Answer

SRVO-047 HVAL (Hardware Velocity Alarm) triggers when an axis velocity exceeds the maximum hardware speed limit, often caused by runaway servo or loose encoder coupling.

Question 2

When using FANUC's Dual Check Safety (DCS), a 'Position/Speed Check' violation alarm does NOT reset automatically after clearing. What must the technician do?

Accepted Answer

Cycle power and confirm the robot is within the safe zone before resuming

Answer

DCS safety alarms require the robot to be physically moved into a safe position and a deliberate operator action (power cycle + confirmation) before the safety system resets.

Question 3

A FANUC R-30iB controller shows a PRIO-155 alarm (User alarm). Where would a maintenance technician find the custom description text for this alarm?

Accepted Answer

In the TP program UALM[ ] configuration under MENU > SETUP > Alarm

Answer

User alarms (PRIO-155) are configured through MENU > SETUP > Alarm, where each UALM[n] entry can have a custom description string assigned by the programmer.

Question 4

To back up FANUC robot programs and system parameters to a USB drive, which image type preserves ALL data including mastering and calibration?

Accepted Answer

IMAGE backup (SYSIMAGE.IMG)

Answer

An IMAGE backup (SYSIMAGE.IMG) creates a complete bit-for-bit copy of the FROM/SRAM memory including mastering data, calibration, system variables, and all programs.

Question 5

A FANUC robot's cycle time has gradually increased over several months. After checking programs, what maintenance item most likely contributes to this degradation?

Accepted Answer

Mechanical wear increasing joint friction and reducing achievable speed

Answer

As harmonic drives and bearings wear, increased friction forces the servo system to reduce speed to stay within torque limits, gradually increasing cycle time.

(FANUC) Fuji Automatic Numerical Control Robotics Certification Practice Test

(FANUC) Fuji Automatic Numerical Control Robotics Certification Practice Test

FANUC Maintenance & Troubleshooting of CNC Robots 3