0759

Common Causes

• Damaged, loose, or poorly seated servo link cables or connectors
• Faulty MF-SAFETY unit
• Failed servo link slave unit on one of the axes
• Outdated or corrupted axis construction definition file

Troubleshooting Steps

1. 1Read the code number shown with the alarm: code 0x50000000 = Safety transmission data mismatched between CPU0 and CPU1 during servo link initialization; code 0x51XX0000 = No frame received from the slave during initialization; XX is the axis ID of the non-responding slave; code 0x520XYYYY = Communication error during initialization; X is the servo link channel, YYYY is the servo controller error status (disconnection, CRC, format, parity, or time-out per bit); code 0x53XX0000 = Slave with axis ID XX did not respond within the allowed time; code 0x54XX0000 = Safety protocol could not be established on the servo link with axis XX; code 0x55XXYYZZ = Safety servo frame communication failed after the protocol was established; XX is the slave address, YY is the failure reason (e.g. CRC error, connection ID error), ZZ is the received safety data; code 0x56000000 = Safety servo transmission data mismatched between CPU0 and CPU1 during operation; code 0xFFFFXXXX = XXXX is the world clock value at the time the safety protocol was raised
2. 2Read the hex code on the alarm screen. 0x50000000 or 0x56000000 means the safety transmission data disagreed between CPU0 and CPU1; 0x51XX0000 or 0x53XX0000 means the slave with axis ID XX did not answer; 0x520XYYYY decodes the channel and error bits (bit9 = disconnection, bit7 = CRC, bit0 = time-out); 0x54XX0000 means the safety protocol could not be established with axis XX; 0x55XXYYZZ means safety frames failed after the protocol was up, with YY giving the reason (04 = CRC error, 03 = connection ID error).
3. 3Lock out the main power and allow the drive bus to discharge before touching any hardware. Inspect and reseat the servo link cables end to end, especially to the slave unit identified by the axis ID in the code; look for pinched jackets, bent pins, or oil contamination in the connectors.
4. 4If the code points to a specific axis (0x51XX, 0x53XX, 0x54XX), swap or replace that servo link slave unit and retest.
5. 5If the code indicates CRC, parity, or format errors across multiple axes, replace the servo link cables first, then the MF-SAFETY unit if the fault persists.
6. 6If hardware replacement does not clear it, update the axis construction definition file to the correct version for this machine configuration.
7. 7If the alarm returns after these checks, record the full hex code and contact Okuma service.