FANUC Fundamentals of CNC Robotics Operation 4 — Questions and Answers
Question 1: During a FANUC mastering procedure using the witness mark method, what must be true before setting the zero point?
- All joints must be at their maximum travel
- Each joint must be aligned so its witness marks are exactly matched (Correct answer)
- The robot must be powered off and restarted
- The payload must be removed from the flange
Correct answer: Each joint must be aligned so its witness marks are exactly matched
Witness mark mastering requires aligning the scribed lines on each joint before recording the zero encoder count.
Question 2: What does the FANUC R-30iB controller's iRCalibration feature automatically compute?
- The robot's TCP from a series of taught approaches to a fixed point (Correct answer)
- The optimal joint speed profile for a given payload
- The servo amplifier current offsets
- The vision camera focal length
Correct answer: The robot's TCP from a series of taught approaches to a fixed point
iRCalibration uses multiple approaches to a reference point to mathematically determine the TCP offset.
Question 3: Which FANUC I/O type is used for high-speed synchronization signals between the robot and an external CNC machine?
- Digital I/O (DI/DO)
- Robot I/O (RI/RO) (Correct answer)
- Group I/O (GI/GO)
- Analog I/O (AI/AO)
Correct answer: Robot I/O (RI/RO)
Robot I/O (RI/RO) points are physically located on the robot arm and are designed for low-latency, high-speed signals.
Question 4: In a FANUC system configured for coordinated motion, what is the 'master' robot's role?
- It provides the reference frame that the 'slave' robot tracks during synchronized motion (Correct answer)
- It controls the E-stop chain for both robots
- It stores all programs for the slave robot
- It performs all load calculations for both arms
Correct answer: It provides the reference frame that the 'slave' robot tracks during synchronized motion
The master robot defines the motion path, and the slave robot moves relative to the master's frame in real time.
Question 5: What is the purpose of the FANUC Payload Estimation function (PAYLOAD IDENTIFY)?
- To automatically calculate tool mass and center of gravity from measured joint torques (Correct answer)
- To set a software torque limit on the J1 axis
- To identify which program last moved the robot
- To estimate remaining servo motor life
Correct answer: To automatically calculate tool mass and center of gravity from measured joint torques
PAYLOAD IDENTIFY moves the robot through specific motions and uses torque feedback to estimate tool mass and CoG.
Question 6: Which FANUC alarm indicates that the robot has exceeded its defined work envelope limit?
- SRVO-023 Stop error excess
- MOTN-023 Joint limit exceeded (Correct answer)
- SRVO-062 BZAL alarm
- INTP-130 Program not found
Correct answer: MOTN-023 Joint limit exceeded
MOTN-023 is triggered when a commanded position would place a joint beyond its software travel limit.
Question 7: In FANUC TP programming, what does the SKIP CONDITION instruction do?
- Skips the next line if a numeric register equals zero
- Abandons the current motion and jumps to a label if a specified condition is true mid-move (Correct answer)
- Skips all lines with a CNT termination type
- Bypasses the current program and runs the next in the queue
Correct answer: Abandons the current motion and jumps to a label if a specified condition is true mid-move
SKIP CONDITION allows the robot to abort a move and branch to a label if the defined I/O or register condition becomes true during motion.
FANUC Fundamentals of CNC Robotics Operation 4
During a FANUC mastering procedure using the witness mark method, what must be true before setting the zero point?