AC Spindle Alarm 27

Alarm code27

The sensor signal (position coder signal) for position control is abnormal.

<1> The signal of the a position coder is disconnected (for all types).

<2> When an MZ or BZ sensor is used with SPM TYPE1 (using the JY2 connector), the amplitude of the sensor signal is excessively small.

<3> When a separate built-in sensor is used with SPM TYPE2 (using the JY2 and JY5 connectors), the amplitude of the spindle sensor signal on the JY2 side is excessively small.

<4> When a high-resolution magnetic pulse coder is used with SPM TYPE2 (using the JY2 and JY5 connectors), the amplitude of the sensor signal on the low-resolution side (128 to 384l) on the JY5 side is excessively small.

<5> When SPM TYPE4 is used, the amplitude of the spindle sensor signal connected to JY5 is excessively small.

1) If this alarm is issued when the motor is deactivated

• • The setting of a parameter is incorrect.
    Referring to Chapter 2 of “FANUC AC SPINDLE MOTOR
    α series Parameter Manual (B-65160E),” check the parameter for sensor setting.
  • (b) The cable connected to JY4 is disconnected. (opposition coder)
    When the opposition coder is used, adjustment is impossible. Replace the cable.
  • The sensor is not adjusted correctly.
    Adjust the sensor signal according to Subsection 4.3.4 of Part I of this manual. If the sensor signal cannot bead justed correctly, or the sensor signal is not observed, replace the connection cable and sensor.
  • The SPM is faulty.
    Replace the SPM or SPM control printed circuit board.

(2) If this alarm is issued when the cable is moved (as in the case where the spindle moves)

• • (a) The connector has a bad contact, or the cable is disconnected.
    The conductor may be broken. Replace the cable. If coolant has penetrated into the connector, clean the connector.

(3) If this alarm is issued when the motor rotates

• • (a) The shielding of the cable between the sensor and the SPMis faulty.
    Referring to Chapter 9, “Connection,” in “FANUC SERVO AMPLIFIER α series Descriptions (B-65162E),” check the shielding of the cable.
  • (b) The signal cable is bundled with the servo motor powerline.
    If the cable between the sensor and the SPM is bundled with the servo motor power line, separate them from each other.

Alarm code28

The sensor signal (for position control) for Cs contour control is abnormal.

1. When a high-resolution magnetic pulse coder is used with SPM TYPE2 (using both of the JY2 and JY5 connectors), the amplitude of the sensor signal on the high-resolution side (1000 to 3000) of the high-resolution magnetic pulse coder on the JY5 side is excessively small.
2. When SPM TYPE4 is used, the amplitude of the spindle sensor (MZ sensor) built into the motor connected to JY5 is excessively small.

Troubleshoot as in the case of alarm code 26.

Content Credit: FANUC Product Manual