SRVO-002

Verify E-stop button state

Inspect the red EMERGENCY STOP mushroom button on the teach pendant. If extended/pressed, it will protrude approximately 8-10mm above the surface. Check for any visible damage to the button housing or rotation mechanism.

Never bypass or defeat E-stop functionality. E-stops are critical safety devices required by ANSI/RIA R15.06 standards.

Release the E-stop button

Firmly grasp the red mushroom head and rotate clockwise (typically 45-90 degrees) until you hear and feel a distinct click. The button should spring back flush with the panel surface or slightly recessed. If the button does not rotate smoothly or click, the mechanism may be damaged.

On older teach pendants with 5+ years of service, the E-stop mechanism can accumulate debris. A stuck button often rotates but won't click or stay released—this indicates internal contact failure.

Clear the alarm and test

Press RESET on the teach pendant or press and hold SHIFT + RESET for 2 seconds. Verify SRVO-002 clears from the alarm log. Navigate to MENU > ALARM > F1 (TYPE) > ALARM LOG to confirm. If alarm immediately returns without touching E-stop, proceed to cable diagnostics.

Check I/O signal *SI[14] E-STOP TP in MENU > I/O > Digital > Signal. This should show ON (1) when released, OFF (0) when pressed. If it shows OFF with button released, the problem is downstream of the button.

Test button mechanical operation

Press and release the E-stop button 3-5 times while observing the alarm response. Each press should immediately trigger SRVO-002. Each release should allow reset. Inconsistent behavior (alarm triggers randomly or won't clear) indicates a failing E-stop switch requiring teach pendant replacement.

Ensure robot cannot move during testing. Verify SERVO OFF is displayed and no motion programs are active.

Inspect cable along entire length

Examine the teach pendant cable from the panel connector to the TP body, paying special attention to high-flex areas within 12 inches of both ends. Look for kinks, cuts, crush damage, or areas where the cable jacket is worn through. Check the strain relief boots at both connectors for cracking or separation.

The most common failure point is where the cable exits the teach pendant body. Flex the cable gently while watching for SRVO-002 to appear—if the alarm triggers during flexing, you've found an intermittent break in the E-stop circuit.

Reseat teach pendant cable connection

Power down the controller completely (not just SERVO OFF). Disconnect the teach pendant cable from the operator panel connector. Inspect connector pins for bending, corrosion, or debris. Clean with contact cleaner if needed. Reconnect firmly until the locking mechanism engages with an audible click. Power up and test.

On R-30iB controllers, hot-plugging the TP cable while powered can damage the FROM board. Always power down completely before disconnecting the teach pendant.

Test with alternate cable position

Secure the teach pendant cable in an unflexed, straight configuration along its entire length. Use temporary cable supports to eliminate all flex points. If SRVO-002 stops occurring, the cable has internal conductor breaks. If a spare teach pendant cable is available, substitute it to isolate cable vs. teach pendant failure.

Fanuc teach pendant cables typically have 5-7 year service life in industrial environments. Document cable installation date and replace proactively if approaching this age, especially in high-use applications.

Check cable continuity on E-stop circuit

With controller powered down and TP cable disconnected, use a multimeter to check continuity between E-stop circuit pins. Consult controller/TP cable documentation for specific pin assignments (typically pins vary by cable model A05B-series). With E-stop released, resistance should be <1 ohm. With E-stop pressed, circuit should be open (infinite resistance).

On R-30iA/iB, the E-stop circuit typically uses pins in the main connector. If you have intermittent continuity (resistance fluctuates when cable is moved), replace the cable immediately—it will fail completely without warning.

Verify E-stop circuit at controller level

Navigate to MENU > I/O > Digital > Input signals. Monitor signal *SI[14] E-STOP TP (signal number may vary—check I/O assignment). With E-stop released, this should read ON (1). Press E-stop and verify it changes to OFF (0). If signal doesn't change states or shows OFF constantly, the fault is in the teach pendant or cable.

You can also check this via ladder logic in MENU > SYSTEM > Variables > $DIN[14] or through the panel DI LED indicators on the controller cabinet if your system has the optional I/O display module.

Test with teach pendant disabled

With robot safeguarded and in a safe state, power down and disconnect the teach pendant cable. Install an E-stop jumper or use a known-good spare teach pendant. Power up. If SRVO-002 does not occur with substitute TP, the original teach pendant has failed internally and requires replacement.

Never operate the robot without a functional E-stop. This test is for diagnosis only. Restore full E-stop functionality before any robot motion.