SRVO-003

Verify three-position switch operation

The deadman switch has three positions: Released (no pressure), Engaged (middle position with moderate pressure), and Panic (fully pressed through). Only the middle position enables robot motion. Practice finding the middle position without moving the robot.

The engaged position typically provides tactile feedback with a slight resistance point. Hold pressure just past the initial click but before the hard stop.

Clear the alarm and resume operation

Press and hold the deadman switch to the middle engaged position. Press the RESET button on the teach pendant (or MENU > ALARM > RESET). Once cleared, press the green cycle start button while maintaining proper deadman pressure to resume motion.

Ensure the robot path is clear and safe before resuming motion. The robot will continue from the interrupted position.

Review operator technique

If SRVO-003 occurs frequently with the same operator, review proper grip technique. The switch should be held with fingers wrapped around the rear handle, thumb naturally resting on the front, providing consistent moderate pressure. Avoid gripping too tightly or tensing during robot motion.

Operator fatigue is a common contributor. If working extended periods, take breaks every 20-30 minutes to prevent grip fatigue and inadvertent switch release.

Verify mode and motion settings

Check that the mode select switch is properly set to T1 (slow speed testing) or T2 (faster teaching speed). In T1 mode, maximum speed is 250mm/sec which gives more reaction time. Navigate to MENU > SYSTEM > Config > Deadman to verify deadman configuration is set to ENABLE.

Use T1 mode for initial teaching and unfamiliar motions. T2 mode requires more experienced operators due to higher speeds.

Test deadman switch functionality

With robot power on and teach pendant in T1 mode, slowly press the deadman switch through its full range. Observe the TP ready indicator (should illuminate only in middle position) and listen/feel for abnormal clicking, grinding, or dead spots. The switch should have smooth, consistent resistance through the engagement zone.

Do not press cycle start during this test. Keep the robot in a safe position away from obstacles.

Check deadman switch status in diagnostics

Navigate to MENU > SYSTEM > Variables > $TP_ENABLE to view real-time deadman status (TRUE when engaged, FALSE when released). While observing this variable, slowly actuate the deadman switch. Any flickering or unexpected FALSE readings indicate switch fault. Also check MENU > I/O > Digital > TP_ENBL input for status.

Use a test program with a slow, simple motion and watch $TP_ENABLE on the status bar while moving. Any momentary FALSE readings will trigger SRVO-003 and indicate intermittent switch failure.

Inspect teach pendant switch assembly

Power down the robot (MENU > SYSTEM > Master OFF, then disconnect main power). Remove the rear teach pendant cover screws (typically 4 screws). Inspect the deadman switch mechanism for broken plastic, worn contacts, loose mounting, or foreign debris. Check that the switch actuator moves freely and returns to neutral position.

Only qualified service personnel should disassemble the teach pendant. Improper reassembly can create safety hazards. Use proper ESD precautions.

Replace teach pendant or deadman switch

If mechanical fault is confirmed, the deadman switch assembly must be replaced. Order Fanuc part number specific to your teach pendant model (iPendant: A05B-2490-C3xx series, older TP: A05B-2301-C3xx series). Complete replacement typically requires teach pendant serial number registration in MENU > SYSTEM > Config > Teach Pendant after replacement.

Keep a spare teach pendant programmed and registered for critical production cells. Teach pendant swap can be done in 5 minutes versus waiting for repair, minimizing downtime.

Perform teach pendant cable flex test

With robot in T1 mode and deadman engaged (without pressing cycle start), slowly flex the teach pendant cable along its entire length, paying special attention to the connector ends and any areas with cable strain relief. Watch for SRVO-003 alarm occurrence. Flex near the pendant body connector and controller connection point while monitoring for faults.

Do not press cycle start during flex testing. Ensure robot is in a safe position before testing.

Inspect cable and connectors for damage

Power down the controller. Inspect the entire teach pendant cable for cuts, pinch points, excessive wear, or damage to the outer jacket. Check both connectors (teach pendant side and controller cabinet side) for bent pins, corrosion, or contamination. On controller side, check connector at the operator panel interface or main CPU board depending on model.

Common failure points are within 6 inches of the teach pendant body where repeated bending occurs, and at the controller cabinet entry point where cables can be pinched by doors or panels.

Verify connector seating and signal continuity

Disconnect and reconnect the teach pendant cable at both ends, ensuring proper alignment and full seating with locking mechanisms engaged. For R-30iA/iB controllers, the TP connector should click into place. Check for proper continuity of the deadman circuit using the controller's built-in diagnostics at MENU > I/O > Diagnostics > TP_Cable test function if available on your software version.

Always power down the controller before disconnecting/reconnecting teach pendant cables to prevent damage to electronic components.