System: FANUC Series 31i-MODEL B
Alarms: FANUC PW0012, PW0013, SV1067, SV1068, SV0484, SV0496, SP1978, EX1019, EX1028
PW0012 User I/O interface error detected (DCS PMC)
PW0013 User I/O interface error detected (PMC)
SV1067 FSSB: Configuration error (software)
SV1068 Repeated detection of safety alarm
SV0484 (X) Safety function error (servo DSP)
SV0484 (Y) Safety Function Error (Servo DSP)
SV0484 (Z) Safety Function Error (Servo DSP)
SV0496 (X) Invalid Axis Data (CNC)
SV0496 (Y) Invalid Axis Data (CNC)
SV0496 (Z) Invalid Axis Data (CNC)
SP1978 (S) Serial Spindle Communication Error
EX1019 Spindle Abnormality
EX1028 Oil Level Drop (Centralized Lubrication)
Let’s take a look at the alarm statuses of the various amplifiers inside the electrical cabinet.
We noticed that the XYZ amplifier is displaying the alarm code “U.” If the letter ‘L’ or “U” appears,
it is highly likely that there is a problem with the amplifier. Look up the amplifier’s alarm codes;
the following is an explanation of the alarm codes.
Alarm Code “U”
(1) Description:
FSSB communication error in the inverter (COP10B)
(2) Causes and Troubleshooting
(a) Replace the SVM fiber-optic cable closest to the CNC that displays “U” (COP10B) (in the
scenario shown in the figure above, this would be the cable between UNIT2 and UNIT3).
(b) Replace the SVM closest to the CNC that displays “U” (in the scenario shown in the figure
above, this would be UNIT3).
(c) Replace the SVM at the COP10B end of the SVM closest to the CNC that displays “U” (in
the scenario shown in the figure above, this would be UNIT2).
(d) Replace the CNC’s servo card.
Based on the above analysis of the causes, we have essentially narrowed down the fault to a
malfunction in either the spindle amplifier or the XY amplifier
Key inspection points: FSSB fiber-optic communication and the servo amplifier side panel. Try
reseating the connectors, as there may be a loose connection. If reseating resolves the issue,
replace the amplifier side panel with a new one to test the system.
If replacing the amplifier side panel still doesn’t resolve the issue, what should be the next step
in troubleshooting?
In the alarm screenshot above, the XY amplifier displays “U,” and the Z amplifier also displays “U.”
According to the amplifier alarm code instructions, you should replace the SVM closest to the
CNC that displays “U.” The above case is for reference only; if you encounter a similar alarm in
the future, you can try replacing the amplifier side panel.