FANUC Spindle Amplifier Alarm Codes and Solutions

Figure 1: FANUC spindle amplifier module.

Spindle Amplifier Alarm Codes and Solutions

The following is a continuation of the previous article, and introduces FANUC spindle drive alarm codes 24-46.

Fanuc Spindle Amplifier Alarm 24: Serial Port Transmission Error

Cause for alarm: It is detected that the CNC current is cut off.
Troubleshooting:
1) Check the command line of the spindle amplifier.
2) The spindle command line and the power line are placed separately.
3) Replace the cable or amplifier.

SP9027 Position Encoder Disconnection

Cause for alarm: The signal of the spindle position encoder is abnormal.
Troubleshooting:
1) Check whether the pins of the spindle feedback line are soldered incorrectly and whether the interface is correct.
2) Check whether the setting parameters of the spindle encoder are consistent with the actual situation.
3) Replace the spindle feedback line, spindle amplifier,or motor encoder.

SP9029 Short-term Overload

Cause for alarm: Excessive load is continuously applied for a certain period of time.
Troubleshooting:
1) Check whether the parameters and ladder diagram (including winding switching) are correct.
2) Reduce the disconnection process and lower the load.

Fanuc Spindle Amplifier Alarm 30: Input Circuit Overcurrent

Reason for alarm:
Overcurrent imbalance is detected at the main circuit input of the public power supply (public power supply alarm displays 1). The public power supply is selected incorrectly, exceeding the maximum output specification of the public power supply.
Troubleshooting:
1) Make sure the public power supply is sufficient.
2) If the amplifier side panel is loose, reinsert the amplifier side panel.
3) If the hardware is damaged, replace the amplifier.

Fanuc Spindle Drive Alarm 31

Fault content: The motor does not rotate at the commanded speed. Instead, it stops, or rotates at a very low speed.
Troubleshooting method:
(1) The motor rotates at a very low speed.
(a) The parameter setting is incorrect. Please confirm the sensor setting parameters.
(b) The motor phase sequence is wrong. Confirm whether the motor phase sequence is wrong.
(c) The motor feedback cable is wrong. Please confirm whether the A/B phase signal is reversed.
(d) Defective motor feedback cable. Rotate the motor by hand, and check whether the motor speed is displayed on the NC diagnostic screen, or whether the speed is displayed on the spindle check board. When there is no speed display, replace the cable or spindle sensor (or motor).

(2) The motor does not rotate at all.
(a) The program to lock the spindle is wrong. Check whether the program locks the spindle.
(b) Defective power line. Please confirm that the motor power line is connected correctly. Check if the magnetic contactor is turned on when spindle switching or output switching is performed.
(c) Defective SPM: Please replace the SPM.

Alarm Code 32

Fault content: The memory of the serial communication LSI is abnormal. Check when the power is turned on.
Troubleshooting method: When the alarm occurs, replace the SPM or SPM control printed circuit board.

Alarm Code 33

Fault content: The DC side discharge circuit is abnormal. The power module is faulty, or the control board of the SPM is faulty.
Troubleshooting method: Replace the control board or the PSM.

Alarm code 34

Fault content: Parameter data outside the allowable range is set.
Troubleshooting method:
Connect the spindle inspection board. "AL-34" and "F-xxx" are displayed alternately on the spindle inspection board, and "F-xxx" indicates the parameter number outside the allowable range. For the correspondence between CNC parameter numbers and ""F-xxx", please refer to the FANUC AC SPINDLE MOTOR αi series parameter manual (B-65280CM).

Alarm Code 36

Fault content: Error counter overflowed.
Troubleshooting method:
(1) The parameter setting is incorrect
(a) The gear ratio parameter setting is incorrect: Check whether the gear ratio data is incorrectly set to an excessively large value.
(b) Position gain is incorrectly set. When the gear ratio data is correct, increase the value of the position gain.

(2) Program error
(a) In the position control mode (rigid tapping, Cs contour control, spindle synchronous control), check whether the motor excitation is turned off (SFR/SRV off).

Alarm Code 37

Fault content: After the emergency stop signal is input, the motor does not decelerate but accelerates. It also occurs when the motor excitation is not cut off (deceleration is not completed) after the emergency stop signal input and the acceleration/deceleration time (the parameter is initially set to 10 seconds).

Troubleshooting method:
(a) The parameter setting of the speed detector is incorrect. Please set the correct value.
(b) The parameter setting value of acceleration and deceleration time is unreasonable. Confirm the parameter setting value and the actual deceleration time, and set a value with a margin for the actual deceleration time.
4082 setting value 2 (time setting during acceleration/deceleration)

Alarm Code 41

Fault content: The signal generation position for one revolution of the α-position encoder is incorrect.
Troubleshooting method:
(a) The parameter setting is incorrect. Please confirm the sensor setting parameters.
(b) Defective α position encoder. Please observe the Z signal of the position encoder, and replace the position encoder when no signal is generated every rotation.
(c) Poor shielding of the cable between the sensor and the SPM. Check the shielding treatment of the cable.
(d) It is tied with the power line of the servo motor. If the cables from the sensor to the SPM are tied together with the servo motor power cables, tie them separately.
(e) Poor SPM. Please replace the SPM or SPM control printed circuit board.

Alarm Code 42

Fault content: The alpha position encoder does not produce a per-revolution signal.
Troubleshooting method:
(a) The parameter setting is incorrect. Please confirm the sensor setting parameters.
(b) Defective α position encoder. Please observe the check pin PSD on the spindle check board. If the signal is not output every turn, replace the connecting cable and position encoder.
(c) Poor SPM. Please replace the SPM or SPM control printed circuit board.

Alarm Code 46

Fault content: The position detector did not correctly detect the signal per revolution during thread cutting operations.
Troubleshooting method: See Alarm Code 41 for troubleshooting of this alarm.