I want to share it to blog CNC machining readers, this occurs when the vertical CNC machine will start operating. At the time of the machine appears alarm turn on "438 Z AXIS: INV.ABNORMAL CURRENT." Then I searched the manual book to solve the problem. In the servo amplifier has also appeared alarm code "b". I followed everything on the manual book disconnect the motor power leads from SVM and check my PE with U, V, or W and the result is ok no problem. Then I disconnect the motor power lead to check its insulation and the results are no problems / ok.
All I have done according to the manual book but to no avail. I tried to change the Axis card that was in front of the motherboard. But still the alarm until I eventually replace the pulse coder, still alarm 438 Z axis: INV.abnormal current. Finally we decided to remove the Z axis motor to ascertain whether the ball screw in trouble, after we motor off (all unopened cable connector). Then the machine turn on. Apparently still alarm as well.
This means ball screw no problem, then my Z axis motor brake check by disconnecting the power cable connector and a cable pulse coder. Connect the 24 volt DC voltage to brake. Once given voltage 24VDC brake, turn the motor shaft by hand turns the motor does not rotate. We feel happy because the problem has been found. Then we opened the motor for the brake repair. (How to repair motor brake my Z axis will post another time).
After the repair is completed we put back on the machine and turn on the machine in alarm is gone and the Z axis zero setting.
Whether you will read another article Fanuc Alarm 300 or Fanuc Backlash Parameter.