SRVO-075

Verify battery failure alarm history

Press MENU > ALARM > F2 [LOG] to view alarm history. Confirm SRVO-062 BZAL alarm preceded the SRVO-075 alarm. Note the affected axis number(s) in the alarm message.

Check the alarm log timestamps to determine if multiple axes lost position simultaneously, which typically indicates main battery failure rather than individual encoder issues.

Check and replace battery if necessary

Navigate to MENU > SYSTEM > Variables to check battery voltage (variable $BATTERY.$VOLT). Normal voltage is 3.0-3.6V. If below 2.7V, replace battery pack. For R-30iA controllers, replace A98L-0031-0025 or A06B-6114-K504 battery packs.

When replacing the battery, complete the swap within 30 minutes to prevent further position loss on other axes. Always verify backup battery is connected before disconnecting main battery.

Reset alarm and jog affected axis

Press RESET key to clear SRVO-075 alarm. Enable T1 mode, hold deadman switch, and jog the affected axis continuously in one direction through at least one complete motor revolution (typically 20-45 degrees of joint motion depending on gear ratio). Monitor teach pendant for alarm clearance.

Ensure the robot has adequate clearance in all directions before jogging. Without established pulse counts, position verification is not available.

Verify pulse count establishment

After jogging through one revolution, the alarm should automatically clear and not return. Verify by checking MENU > SYSTEM > Master/Cal > Pulse Match screen. The 'Pulse Count' field should display established values rather than asterisks or dashes.

If alarm persists after jogging 2-3 full revolutions, the pulse coder itself may be damaged and requires encoder replacement, not just re-mastering.

Proceed with mastering procedure

Once pulse count is established, perform mastering using MENU > SYSTEM > Master/Cal. Use either Quick Master (if reference marks are available) or Single Count Master method. Record new master data to FROM using MENU > FILE > Backup/Restore.

Verify CMAL alarm in history

Access MENU > ALARM > F2 [LOG] to confirm SRVO-073 CMAL (Checksum Alarm) preceded SRVO-075. Note the specific axis affected and timestamp. Multiple CMAL occurrences indicate ongoing noise issues requiring immediate attention.

Repeated CMAL alarms indicate serious electrical problems that can cause unpredictable robot behavior. Do not continue normal operations until the root cause is resolved.

Inspect encoder cable and connections

Power down the robot and inspect the pulse coder cable for the affected axis. Check connector CN1 on the amplifier (servo amp) and the motor-side connector for corrosion, bent pins, or contamination. Verify proper shielding continuity and ensure cable is not routed near high-voltage lines or welding equipment.

Pulse coder cables are typically gray and shielded. Check for cable damage at stress points near the J2 and J3 arm rotations where flexing is most severe. Resistance between cable shield and ground should be less than 1 ohm.

Check grounding and EMI sources

Verify robot base and controller cabinet grounding resistance is less than 0.1 ohm to facility ground. Inspect for nearby EMI sources including servo welders, large contactors, or VFDs. Check parameter 2041 (Encoder Selection) is set correctly for the installed encoder type (typically 2 for alphaiA encoders).

On R-30iB controllers, check parameter 8131 (Encoder Communication Error Mask) - this should be default (0). Incorrect settings can cause false CMAL alarms.

Clear alarm and establish pulse count

Press RESET to clear SRVO-075. Jog the affected axis smoothly through one full motor revolution. Monitor for alarm recurrence during jogging - if CMAL reappears during motion, the noise source is still active or the encoder is failing.

If CMAL alarm reoccurs during slow jogging, do not proceed with mastering. The encoder or cable requires replacement.

Test and validate before mastering

After pulse count is established and alarm clears, jog the axis through its full range of motion slowly while monitoring for alarm recurrence. Check MENU > STATUS > Servo Display and verify encoder feedback is stable. If no alarms occur for several full cycles, proceed with mastering procedure.

Verify recent maintenance history

Confirm if encoder, motor, or amplifier was recently replaced on the affected axis. Check maintenance records or MENU > ALARM > F2 [LOG] for any SRVO alarms indicating previous servo system issues. New encoders will immediately show SRVO-075 on power-up.

After encoder replacement, you may also see SRVO-065 (Motr/Enc Combination) if the encoder serial data does not match controller records. This is normal and will clear after pulse establishment and mastering.