SRVO-043

Review motion program acceleration parameters

Navigate to MENU > NEXT > SYSTEM > Motion and check the acceleration override settings. Review your TP program for FINE positioning versus CNT (continuous) motion. Excessive CNT values (CNT100-CNT150) combined with high speeds cause rapid deceleration at corners. Reduce CNT values to CNT50-CNT75 or use FINE at critical points to extend deceleration time.

Use Data > Host Comm > Error Log to check the exact position/line number where SRVO-043 occurred. This will identify the specific move causing regeneration issues.

Reduce overall speed override and acceleration

Temporarily reduce speed override to 50-75% from the teach pendant (hold SHIFT + speed keys) and test the cycle. If alarm clears, the motion profile is the issue. Check system variable $SCR.$MAXACCEL (parameter 1420-1427 for each axis) to reduce maximum acceleration values by 10-20%.

Modifying $MAXACCEL affects all programs. Create a backup before changes using MENU > FILE > Backup > to USB.

Add strategic dwell times for thermal recovery

Insert WAIT 0.5 or WAIT 1.0 (500ms-1000ms) commands after high-speed moves in your TP program, especially before the next rapid motion. This allows the regenerative resistor to cool between energy bursts. Monitor DC bus voltage at MENU > NEXT > SYSTEM > Variables > $MOR_GRP[1].$DCVOLT to verify voltage drops below 400V during dwells.

For palletizing: add dwells at the approach point before each layer change. For machine tending: add dwells during part load/unload wait states where robot motion isn't time-critical.

Analyze energy consumption pattern

Enable energy monitoring by setting parameter 19730 (Energy monitor enable) to 1. Run your cycle and review MENU > STATUS > Energy to see regenerative power peaks. Values consistently above 5-7kW indicate motion profile redesign is needed. Consider splitting single long moves into multiple shorter segments with lower acceleration.

R-30iB Plus controllers have enhanced energy monitoring. Check the regenerative duty cycle on the energy graph - sustained periods above 80% will trigger SRVO-043.

Verify payload configuration accuracy

Navigate to MENU > SETUP > Payload and confirm the payload number being used. Then check MENU > SETUP > Frames > Payload and verify the weight (kg) and center of gravity values match your actual end-effector and workpiece. Overestimated payload causes the controller to use excessive braking force, generating more regenerative energy than necessary.

Incorrect payload settings compromise robot performance and safety. Always perform a payload identification routine after changes: MENU > SETUP > Payload > Payload ID.

Reduce speed on gravity-assisted downward moves

Identify downward vertical moves in your TP program and add speed modifiers. Use 'AP_LD' motion group instruction or inline speed reduction: L P[1] 2000mm/sec FINE changes to L P[1] 1000mm/sec FINE for downward moves. Focus on moves where J3 angle decreases significantly (robot arm extending downward) or J2 moving forward/down with payload.

Use position register offsets to create approach points 100-200mm above pickup/place points at higher speed, then slow down for the final vertical descent. This maintains cycle time while reducing regeneration.

Enable gravity compensation optimization

Check parameter 2052 (Gravity compensation) is set to 1 for each vertical axis. For R-30iB controllers, verify parameter 2056 (Enhanced gravity comp) is enabled. This reduces servo braking requirements on downward moves. Also check parameter 1426 (J3 motor torque limit) - if set too high (>100%), reduce to 90-95% to limit regenerative capacity.

After enabling enhanced gravity compensation, perform a slow jog test of the vertical axis. The axis should require minimal position correction during downward motion, indicating optimal servo balance.

Implement controlled lowering profile

For repetitive vertical moves, use Joint motion (J P[x]) instead of Linear (L P[x]) for downward moves when path accuracy isn't critical. Joint moves distribute motion across multiple axes, reducing single-axis regeneration. Alternatively, use circular motion (C P[x]) with intermediate points to create gradual descent rather than direct vertical drop.

Joint motion changes the tool path. Verify clearances and collision zones after modifying Linear to Joint moves.

Inspect regenerative resistor physical condition

Power down the robot and open the controller cabinet. Locate the regenerative resistor bank (typically mounted on rear panel or separate heat sink). Visually inspect for discoloration (browning/blackening indicates overheating), cracks in ceramic resistors, loose connections, or burnt smell. Check mounting bolts are tight. Measure resistance with multimeter - should match nameplate value (typically 20-40 ohms for most R-30iA/B systems).

LOTO required. Wait 15 minutes after power-down for DC bus capacitors to discharge before touching any components. Verify voltage at TP8/TP9 test points is below 50VDC.