SRVO-050

Verify alarm details and axis

Press RESET on the teach pendant, then navigate to MENU > ALARM > F1 (HIST) to view the alarm history. Note which axis triggered SRVO-050. Check the sub-code if present, which indicates the specific joint (1=J1, 2=J2, etc.). Record the position data at time of alarm.

The alarm history timestamp can help correlate the collision with specific program lines. Use MENU > ALARM > F5 (DETAIL) to see additional diagnostic information including estimated disturbance torque values.

Physical inspection of affected axis

With the robot disabled (DEADMAN released), manually inspect the axis that triggered the alarm. Look for impact marks, scratches, or deformation on arm segments, J3 arm casting, and wrist assembly. Check end-effector mounting bolts for looseness. Rotate the affected joint manually to feel for binding, roughness, or debris.

Ensure all servo power is OFF and E-Stop is engaged before manually moving axes. Be aware of suspended loads and gravity drop on J2/J3 axes with failed brakes.

Inspect work envelope and peripherals

Examine the robot work area for displaced fixtures, workpieces left in unexpected positions, or changes to the cell layout. Check for interference with welding cables, dress-out packages, air/water hoses, or vision system components. Verify that all fixtures are properly secured and positioned according to cell layout drawings.

Use the teach pendant to jog the robot back through the motion path in T1 mode at low override (5-10%) to identify the exact point of collision. Watch for near-misses that might indicate fixture shift or programming error.

Review program and position data

Navigate to the program that was running when the alarm occurred (MENU > SELECT > Program). Use STEP or FWRD to advance through the motion instructions near the alarm point. Check for recently modified positions, incorrect approach vectors, or missing offset calculations. Verify TCP (Tool Center Point) settings at MENU > SETUP > Frames > Tool Frame match the actual tooling configuration.

Never assume program positions are correct after a collision. Always re-teach critical points and verify clearances before running in AUTO mode.

Test in T1 mode with collision detection active

After clearing the obstruction and verifying the path, reset the alarm and switch to T1 mode. Enable servo power and run the program at 5% override while observing all axes. Monitor for repeated alarms, unusual sounds, or hesitation. Gradually increase override to 25%, 50%, then 100% T1 speed before switching to AUTO mode.

If SRVO-050 recurs at the same position without visible collision, the issue may be payload-related or mechanical wear rather than obstruction.

Verify payload settings

Navigate to MENU > SETUP > Payload. Check that the payload number being used matches the actual tooling. Verify Payload Weight (kg), Center of Gravity (X, Y, Z in mm from J6 flange center), and Inertia values. Compare against tooling specifications or previous known-good configurations. Check that the program selects the correct payload using PAYLOAD[#] instruction.

Use the Payload Identification function on R-30iB controllers: MENU > SETUP > Payload > F3 (UTIL) > Payload ID. This automated routine moves the robot through test motions to calculate actual payload parameters, eliminating guesswork.

Verify maximum payload capacity

Check robot nameplate or MENU > SYSTEM > Variables > $MAXPAYLD[group] to confirm rated payload capacity. Weigh the end-effector assembly including tooling, mounting brackets, and typical workpiece. Ensure total mass does not exceed robot capacity. Account for offset masses that increase effective moment loading on wrist axes.

Exceeding rated payload capacity voids warranty and can cause premature mechanical failure, gear damage, and servo amplifier damage. Overloaded wrist axes (J4/J5/J6) are particularly vulnerable to bearing and gear damage.

Review motion parameters and CNT values

Examine the motion statements in the program for aggressive speeds with heavy payloads. Check corner rounding values (CNT) - CNT100 with heavy loads at high speed generates very high acceleration forces. Consider reducing speed registers, increasing acceleration/deceleration time, or using lower CNT values (CNT25-50) for heavy payload applications.

High-speed palletizing and material handling applications often require speed-dependent payload switching. Use multiple payload definitions and conditional logic to select appropriate parameters based on whether the gripper is loaded or empty.

Adjust collision detection sensitivity

Navigate to MENU > SYSTEM > Variables. Check $MOTYPE (motion type) and $DMR.$OPTION[1] (collision detection enable). Review collision detection level at system variable $DMR.$SENSLVL (range 1-8, default typically 4). If legitimate heavy payloads trigger false alarms, consider increasing this value to 5 or 6, which reduces sensitivity.

Reducing collision detection sensitivity (higher values) decreases robot safety and may allow actual collisions to go undetected. Document all changes and re-evaluate safety risk assessment when modifying these parameters.

Check disturbance observer parameters

Access MENU > MAINTENANCE > F1 (AXIS) > select affected axis. Check disturbance observer compensation settings. For chronic payload-related alarms, verify parameters $DIST_OBS[axis].$ENABLE and $DIST_OBS[axis].$LEVEL are appropriate. Review alarm history detail for estimated disturbance torque values to compare against thresholds.

R-30iB Plus controllers with advanced servo tuning allow per-axis collision sensitivity adjustment. This is useful for applications like deburring or force-controlled assembly where external forces are expected on specific axes.