CNC
TroubleShooting
0-C/D Series
Alarm 401
1-2 Axis VRDY Off
Alarm Code:
401
Alarm Name:
1-2 Axis VRDY Off
Description:
The 1 or 2
st
nd
axis servo amplifier READY signal (DRDY) went off.
Alarm 401 indicates that the servo amplifier is either not turned on or the servo amplifier has turned off
during operation.
Troubleshooting Steps:
1. Other Alarms
If another servo alarm (e.g., Alarm 414, 416, etc.) occurs along with Alarm 401, follow the
troubleshooting procedure for the other alarm. In this case, Alarm 401 is just a secondary message
due to the servo amplifier dropping out as a result of the primary alarm message.
2. Servo Amplifier LEDs
Check for alarm LEDs on the servo amplifier. If an LED is lit, go to the appropriate Servo Maintenance
Manual for troubleshooting information. See the Public Links for the manual references.
3. Servo Amplifier AC Power
Check the AC power input to verify if power is being applied to the servo amplifier. Proper voltage
levels are 200 – 230 VAC (+10%, -15%).
4. ESTOP Signal
Check if the ESTOP signal is applied to the servo amplifier.
4.1. For S series, this is 100VAC at T1 terminals 3-4. For C series and SVU-C servo amplifiers, this is
100VAC at T1 terminals 5-6. The spec is 100VAC (+10%, -15%). An overvoltage at this signal
can cause damage to the internal MCC contactor.
4.2. For all Alpha servo amplifiers, this is a 24VDC signal at CX4 pins 2 – 3.
4.3. Beta amplifiers use a 24VDC signal at JX5 pins 17 – 20.
5. Cable
Check the servo command cable. An open connection on one of the conductors can result in this
alarm.
GE Fanuc Automation N.A., Inc.
07/21/00
This Application Note is intended for general informational purposes only, and is not intended as a substitute for the advice of a qualified technician who is familiar with a specific
control application and who has reviewed the hardware and software to determine safe operation and suitability of purpose. While efforts have been made to be accurate, the
information contained herein does not purport to cover all details or variations in hardware or software, nor to provide for every possible contingency with respect to installation,
operation, or maintenance. This Application Note is based on information available at the time of its publication which is subject to change, and GE Fanuc Automation assumes no
obligation of notice to holders of this document with respect to changes subsequently made. GE Fanuc Automation makes no representation or warranty, whether express, implied,
or statutory, with respect to, and assumes no responsibility for, the accuracy, completeness, sufficiency, or usefulness of the information contained herein, and disclaims any liability
of any kind whatsoever for any claims arising from its use. No warranties of merchantability or fitness for a particular purpose shall apply.
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6. CNC Axis PCB
Problem may exist in the CNC axis control PCB. Replace the PCB.
7. CNC Main PCB
Problem may exist in the Main PCB or Option 2 PCB, depending on which axis is in alarm. Replace
the PCB.