1151

Common Causes

• Defective inverter unit control board (#1, #27-#44 internal errors)
• Low control board battery voltage: +/-12 V (#2) or 5 V (#11), possibly a power unit problem if several inverter units alarm together
• Shorted inverter bridge, IPM protection trip or motor overcurrent (#12, #13, #14) from a motor or cable short
• Corrupt or incompatible optional program file (#3)
• Watchdog, loop or interruption errors (#20-#31) indicating control board failure

Troubleshooting Steps

1. 1Read the code number shown with the alarm: code #1 = Control board error; code shows the board error content; code #2 = Voltage drop of +/-12 V battery for control board; code #3 = OPF (optional program file) error; code: 1 ID code error, 2 end code error, 3 sum check error, 4 board name error; code #11 = Voltage drop of 5 V battery for control board; code #12 = Inverter bridge shorted; code #13 = IPM protective function activated; code #14 = Motor overcurrent; code #20-#25 = INT loop errors (INT, INT5 through INT1)
2. 2Read the character string after the alarm number. This is the key branch: it tells you whether the fault is the control board, a battery voltage, the power stage, or the optional program file.
3. 3#12, #13 or #14 (bridge shorted / IPM protection / motor overcurrent): lock out and tag out the machine and allow the DC bus to discharge before touching anything. Then disconnect the motor power cable at the inverter and megger/continuity-check the motor and cable for a phase-to-phase or phase-to-ground short. If the motor and cable are clean, the inverter unit is faulty.
4. 4#2 or #11 (control board battery voltage low): if several inverter units alarm at once, suspect the power unit supply; if only one unit alarms, that inverter unit's control board is at fault.
5. 5#3 (OPF error): the code gives the file fault (1 = bad "OPF1" ID code, 2 = bad "ED" end code, 3 = sum check error, 4 = board name error); the optional program file is corrupt or incompatible with the inverter unit and must be reloaded or matched by Okuma service.
6. 6#1, #20-#29, #30-#44 (control board, loop, watchdog, interruption or peripheral errors): these are internal to the inverter unit; after a power cycle to confirm the fault is solid, replace the inverter unit.
7. 7If the alarm returns after the indicated unit or file is corrected, record the alarm number, character string and code and contact Okuma service.