Applicable Systems
Series 0i
Series 16/18/21
Alpha
Beta
Symptoms
The servo control unit reports alarm SV 458 (CURRENT LOOP ERROR) on the Y. The servo amplifier for the Y may display an error state on its status LEDs. The axis may stop or fail to move until the condition is corrected.
Possible Causes
- Y servo amplifier fault: CURRENT LOOP ERROR
- Y servo amplifier wiring or connector issue
- Y servo amplifier power supply problem
Troubleshooting Steps
- Step 1: Check the Y servo amplifier status LEDs and record the displayed state.
- Step 2: Verify all power and signal cables to the Y servo amplifier are securely connected.
- Step 3: Measure the Y amplifier DC link and control voltages per the maintenance manual.
- Step 4: If the Y amplifier is faulty, replace it with a matching FANUC unit.
How to Reset
Power off the machine, correct the fault condition, power on, and press RESET. If the alarm reappears, service the servo amplifier.
Common Replacement Parts
- varies: Y servo amplifier (if confirmed faulty)
Frequently Asked Questions
- Q: What does Fanuc SV 458 Y alarm mean?
Fanuc SV 458 Y indicates a servo alarm (CURRENT LOOP ERROR) on the Y. Check the servo amplifier and its connections.
Source: HelmanCNC.com - https://www.helmancnc.com/fanuc-alarm-codes-list/ (servo alarm with n-th axis)
Category: CNC