SRVO-053

Perform visual collision inspection

With servo power OFF, manually move each axis of the robot through its range of motion. Feel for binding, unusual resistance, or debris in joints. Inspect the end-effector, cables, and dress-out for contact marks or deformation. Check for fixtures that may have shifted into the robot envelope.

Ensure servo power is OFF and HOLD-TO-RUN is not bypassed before manually moving the robot.

Review alarm history and position data

Press MENU > ALARM > F5 LOG to view alarm history. Note the axis number in the alarm detail (e.g., 'J3'). Press MENU > SYSTEM > F1 Variables > $DMR_GRP[grp].$DMR_STS to check disturbance status. Check position registers when alarm occurred to identify the exact location of contact.

If the same axis faults at the same position repeatedly, use World Model collision zones or add a safety margin to the taught points in that area.

Test axis motion in isolation

After clearing obstacles, move to MENU > NEXT > JOG. Enable T1 mode at 5% speed override. Jog only the affected axis through full range while monitoring for unusual sounds or hesitation. Gradually increase override if motion is smooth.

Keep hand on DEADMAN switch and maintain clear line of sight to the entire robot during test motion.

Adjust disturbance threshold if needed

Navigate to MENU > SYSTEM > F1 Variables > enter $SCR.$DISTURBTIME[grp,axis] to view current threshold. Default is typically 50ms. If legitimate application forces trigger nuisance alarms, this can be increased to 100-200ms. Also check $SCR.$DISTURBTRQ[grp,axis] torque threshold percentage (default 150%).

Increasing thresholds reduces collision protection sensitivity. Only adjust after confirming no mechanical issues exist and documenting baseline values first.

Verify payload configuration

Navigate to MENU > SETUP > Payload. Check that the correct payload number is active (typically displays as 'PAYLOAD[1]'). Review Weight (kg), X, Y, Z center of gravity offsets, and inertia values. Compare against tooling drawings or use FANUC's PayloadID if available on your controller.

Wrist axes (J4/J5/J6) are most sensitive to payload errors. A 2kg error on a small robot can easily trigger SRVO-053 during rapid wrist motion.

Perform payload identification

If PayloadID is installed: MENU > SETUP > Payload > F2 PayloadID. Select the payload number, press DETAIL, then START. The robot will execute automated motion to calculate actual mass and inertia. If not available, carefully weigh the tool and measure the center of gravity from the tool mounting flange.

PayloadID requires 500mm clearance in all directions. Ensure adequate space before starting the automated routine.

Check for payload switching errors

If your application uses multiple tools, search the TP program for PAYLOAD[X] instructions. Verify the correct payload is set before each tool operation. Check MENU > SYSTEM > Variables > $PAYLOADS[grp] to confirm which payload is currently active matches the installed tooling.

Common mistake: changing tools but forgetting to update payload in recovery routines or when running production programs out of sequence.

Review motion speed and acceleration

High speed motion with incorrect payload amplifies disturbance. Check CNT (corner rounding) values in motion instructions - CNT100 or FINE with heavy tools causes high deceleration torque. Review MENU > SETUP > AccSet for acceleration limits. Consider reducing to 80% if payload uncertainty exists.

J5 (wrist bend) is most vulnerable to payload-induced SRVO-053 because it carries the full moment arm of incorrectly specified tool mass.

Check ambient temperature and warm-up

Review MENU > SYSTEM > F1 Variables > $THRMCOM[grp,axis].$TEMP to view motor temperatures. Below 15°C, grease becomes stiff. Run a warm-up program jogging each axis at 30% speed for 5 minutes before production. Check $THRMCOM[grp,axis].$COAST_TIME for brake timing values that may indicate release issues.

In cold environments below 10°C, SRVO-053 on startup is common. Some sites implement heated enclosures or automatic warm-up routines triggered by temperature sensors.

Test brake release functionality

With robot in safe position and servo ON, listen for brake release click when enabling servos. Press MENU > SYSTEM > Master/Cal > Brake Check to access brake test (if available). With servo OFF, check if axis drifts under gravity - excessive drift indicates brake wear, no drift with servo ON may indicate brake not releasing.

During brake testing, robot axes may move unexpectedly. Ensure adequate clearance and E-Stop access.

Inspect reducer and bearing condition

Manually rotate the affected axis with servo power OFF. Feel for notchy resistance, grinding, or tight spots indicating reducer wear or bearing damage. Check maintenance logs for grease service intervals - reducers typically need regreasing every 3-5 years depending on duty cycle. Refer to MAINTENANCE > F3 Life for axis runtime hours.

J1 base axis and J3 elbow commonly develop reducer wear first due to constant gravity load. A metallic grinding sound during manual rotation is immediate cause for reducer inspection.