MOTN-023

Identify the singularity position

Move to the alarm position in TEACH mode at low speed (5-10%). Press POSN on the teach pendant and check the Joint display. Note J5 value - if between -5° and +5°, you're in wrist singularity territory. Also check the CONFIG status line for any singularity flags.

Use MENU > NEXT > STATUS > Show Position to see real-time joint angles and configuration flags. The 'S' flag in the configuration string indicates singularity region.

Check program motion type

Review the program line causing the alarm. Press SELECT, navigate to the target position. Check if it's Linear (L) or Joint (J) motion. Linear moves through singularities are particularly problematic because the controller must maintain Cartesian path accuracy through the unstable region.

If possible, change Linear moves (L) to Joint moves (J) when working near singularities. Joint moves don't require continuous inverse kinematics solving and can pass through singularity regions more reliably.

Re-teach position with modified wrist angle

Move the robot away from the point, rotate J5 to at least ±15° from 0°, then adjust J4 and J6 to achieve the same TCP orientation. Use COORD > JOINT on teach pendant to manually jog J5. Verify the new position maintains required tool orientation using COORD > USER or TOOL.

Ensure adequate clearance from peripheral equipment when adjusting wrist angles. The TCP position remains the same but the robot arm configuration changes.

Modify tool approach angle if applicable

If the application permits, reorient the tool approach angle by ±10-30° to naturally move J5 away from 0°. Use COORD > TOOL to verify orientation changes, or add a PR offset to rotate about the approach axis. Test motion from multiple approach directions.

For process applications like welding or dispensing, a 15° tool tilt often provides better singularity clearance without impacting quality.

Identify the problematic motion segment

Note the line number where MOTN-023 occurs. In the program, check both the current position and the previous position. Use TOUCHUP on each point and observe joint angles, particularly J5. A linear move where J5 crosses through 0° between two points will trigger this alarm.

Use Step Forward (FWD) in TEACH mode at 1-5% override to slowly execute the move and pinpoint exactly where the singularity occurs along the path.

Add intermediate waypoint(s) to route around singularity

Insert a new point between the start and end positions. Position this waypoint with J5 at ±20° or more from 0°, effectively creating an arc path that avoids the singularity zone. Use COPY/PASTE to insert the line, then TOUCHUP to adjust. Set as CNT (continuous) with appropriate value (CNT 50-100) for smooth motion.

Verify the new path doesn't create interference with fixtures, parts, or cell boundaries. Test at reduced speed (25% override) first.

Enable and configure Wrist Joint Avoidance

Navigate to MENU > SETUP > Motion > Wrist Singularity Avoidance. Set $SCR.$SING_WRIST to TRUE if available (requires appropriate software option). This allows the controller to automatically deviate from pure linear paths near singularities. Adjust $SCR.$SING_WJTH (threshold angle, typically 5-10°).

This feature is part of the Enhanced Wrist Singularity Protection option (R853). If not present, you must use waypoint routing. Check MENU > NEXT > System > Software Options to verify availability.

Consider converting to Joint motion

If Cartesian path accuracy isn't critical for this move, change the motion type from Linear (L) to Joint (J). Edit the program line, change L to J. Joint moves calculate a direct joint interpolation that inherently avoids singularity issues, though the TCP path will not be straight.

Joint moves are typically 15-30% faster than linear moves and are immune to singularity alarms, making them ideal for non-process moves like approach and retract motions.

Check for overhead/centered position geometry

Display the current position using POSN and check Cartesian coordinates in World frame (COORD > WORLD). Calculate the radial distance from J1 axis: sqrt(X² + Y²). If this value is less than 200-300mm and Z is highly positive (overhead), you're likely in shoulder singularity region.

On teach pendant, press and hold SHIFT while pressing POSN to toggle through different coordinate displays quickly.

Relocate the work position if possible

If application allows, shift the taught position 300-500mm away from being directly over J1 axis. This provides adequate radial offset. Use COORD > USER or WORLD to jog in X/Y plane away from center. Maintain Z height and orientation as required by application.

Verify reach limits and ensure the new position doesn't exceed the robot's work envelope. Check J1, J2, J3 soft limits in MENU > SETUP > Frames > Joint Limits.