Yes, there is a difference in system operation when control power supply for a servo amplifier is shut down.
The ALPHA5 series or later supports the MICREX-SX fail-soft operation, but the FALDIC-α series does not.

 

1) Operation when control power supply is shut down
    When the servo amplifier is not registered for fail-soft operation
     FALDIC-α
        The MICREX-SX does not detect the disconnected servo amplifier and continues operation.
      ALPHA5 or later
        The MICREX-SX detects the disconnected servo amplifier and goes into a fatal fault condition.

 

2) Operation when control power supply is shut down
     When the servo amplifier is registered for fail-soft operation
      FALDIC-α
         The MICREX-SX does not detect the disconnected servo amplifier and continues operation.
         When the control power supply for the amplifier is turned on again, the MICREX-SX temporarily detects a nonfatal fault,

         and then starts operation.
      ALPHA5 or later
         The MICREX-SX detects the disconnected servo amplifier and continues operation in a nonfatal fault condition.

 

For more information, refer to the user’s manual 'Fuji Servo System ALPHA7 SX type' (24C7-E-0135)