2174

Common Causes

• Servo link cable or connector loose, damaged, or broken (bit 8 disconnection, bit 0 time-out)
• Faulty inverter unit control board
• Faulty FCP board on the NC side
• Noise or data corruption on the link (CRC, format, or parity errors)

Troubleshooting Steps

1. 1Read the code number shown with the alarm: code bit 15 = 2nd B-buffer error; code bit 14 = 2nd A-buffer error; code bit 13 = 1st B-buffer error; code bit 12 = 1st A-buffer error; code bit 11 = MT buffer error; code bit 10 = Relay processing error; code bit 9 = Data over error in the receiving part of the interface; code bit 8 = Disconnection on the servo link
2. 2Read the YYYY bit field in the code: bit 8 set means a disconnection, bit 0 a time-out, bit 5 a CRC error, bit 1 a parity error; use the highest set bit to direct the check.
3. 3Bit 8 (disconnection) or bit 0 (time-out): lock out power, then physically trace the servo link cable from the FCP board through to the inverter unit, reseating every connector and checking for a cut, crushed, or oil-soaked cable.
4. 4Bit 5 (CRC), bit 4 (format), or bit 1 (parity): suspect noise or a marginal connection; check that link cables are routed away from power cables and that shielding/grounding is intact.
5. 5Bit 10 (relay processing error) or buffer errors (bits 11-15): the error is between units on the link; check the connectors at each inverter unit in the chain, not just the one named in the object.
6. 6If cabling and connectors are confirmed good, replace the inverter unit control board for the named axis; if the alarm persists across axes, the FCP board is the suspect.
7. 7If the alarm returns after these checks, record the full XXXXYYYY code and object and contact Okuma service.