Fanuc Alarm 750 Serial Spindle Alarm Information by KFASLLC

KFAS: Fanuc CNC Parts, Service, & Repair

Fanuc SERIAL SPINDLE ALARM 750

Alarm 750 Description: Serial Communication error between the CNC and Spindle Amplifier

Alarm 750 is only generated if the spindle amplifier does not become normal state during CNC power on sequence.
This alarm does not occur once the system becomes ready including the spindle system .
After the system becomes ready, if there are any problem with the serial spindle, alarm 749 is instead issued.

Causes
(1) Optical cable is in poor contact or power is not supplied to the spindle amplifier.

(2) The display of spindle amplifier shows "SU–01" or "24" at the CNC start up.
In this case, record the status LED and refer to Fanuc serial spindle or Alpha Spindle alarm codes for further troubleshooting.

(3) Serial Spindle parameter settings are incorrect.
Check CNC Diagnostics 409 for more information if there are no alarms on the spindle amplifier itself (i.e. the status LEDs show "- -")

#7 #6 #5 #4 #3 #2 #1 #0
DGN 0409 SPE S2E S1E SHE

#3 (SPE) 0 : The serial spindle parameters satisfies the starting conditions for spindle amplifier.
1 : The serial spindle parameters DO NOT satisfy the starting conditions for spindle amplifier.
Check: Confirm that serial spindle related parameters usually (parameter #4000+ area) are set according to your machine's specification (check against backup list). Relevant material: Alpha Spindle Parameter Manual B-65160E.

#2 (S2E) 0 : The 2nd spindle (if equipped) is normal at the start up .
                1 : The 2nd spindle (if equipped) is ABNORMAL at the start up.
Relevant material: Alpha Spindle Maintenance Manual B-65165E.

#2 (S1E) 0 : The 1st spindle (if equipped) is normal at the start up .
                1 : The 1st spindle (if equipped) is ABNORMAL at the start up.
Relevant material: Alpha Spindle Maintenance Manual B-65165E.

#0 (SPE) 0 : Serial Spindle Control module on the CNC side is normal.
                 1 : Serial Spindle Control module on the CNC side is ABNORMAL.
Depending on the CNC control model, either the serial spindle control module or main control board may need to be replaced. Refer here for more information.

KFASLLC can help you determine the cause of Fanuc alarm 750