Maintenance & Troubleshooting of CNC Robots Flashcards

A FANUC R-30iB robot displays a SRVO-062 (BZAL Alarm) on multiple axes simultaneously after a power outage. What should the technician do first?

Answer: Check and replace the controller's SRAM backup battery, then perform mastering

SRVO-062 BZAL indicates battery alarm on the pulse coder; when multiple axes show this after a power outage, the controller SRAM battery is depleted and must be replaced before mastering is redone.

During FANUC robot path verification after maintenance, the robot overshoots target positions consistently on high-speed moves. Which parameter adjustment should the technician investigate first?

Answer: Tune the servo loop gain (KV or KPROP) via FANUC's servo tuning utility

Consistent overshoot on fast moves typically indicates servo gain (KV/KPROP) is too high or too low, and the FANUC servo tuning utility allows safe incremental adjustment while monitoring the response.

A FANUC Collaborative Robot (CR series) stops unexpectedly in production. After confirming no physical contact occurred, the technician should check which system first?

Answer: The Force/Torque sensor calibration and sensitivity threshold settings

CR-series collaborative robots use integrated force/torque sensing to detect contact; false stops typically result from miscalibrated or overly sensitive thresholds that must be reviewed in the safety configuration.

What is the function of the FANUC 'Quick Master' (or Single-Axis Master) procedure?

Answer: Re-establishes the reference for a single axis without disturbing others, used after motor/encoder replacement on one joint

Quick Master (Single-Axis Master) allows re-mastering of only the affected joint by positioning it at its reference mark, leaving the other axes' mastering data intact.

A FANUC robot's collision detection (SPEED CHECK alarm) triggers repeatedly during a specific TP instruction. The tooling and payload settings are correct. What is the next troubleshooting step?

Answer: Increase the collision detection sensitivity level (or adjust the torque model) for that motion segment

If collision detection false-triggers on a specific motion, adjusting the collision detection sensitivity level or refining the torque model for that segment prevents nuisance alarms without disabling safety.

In a FANUC CNC robot cell, the Programmable Machine Controller (PMC) ladder logic is used to:

Answer: Control I/O interlocks, sequence logic, and interface between the CNC and external machine signals

The PMC executes ladder logic to manage I/O sequencing, safety interlocks, and communication handshaking between the robot CNC controller and peripheral machine equipment.

After installing a FANUC robot axis servo amplifier replacement, the technician should verify the amplifier's axis assignment by checking:

Answer: The amplifier's DIP switch or parameter setting that assigns it to the correct axis number

FANUC servo amplifiers use DIP switches or software parameters to define which axis they control; an incorrect assignment will cause the wrong joint to respond, requiring verification before powering up.