130-00A3

Check DC bus voltage status

Navigate to Test > Service > System Status > Drive Status. Check the DC bus voltage display for each drive module. Normal operating voltage should be 560-660V for standard three-phase supplies.

The drive modules share a common DC bus - if all axes show no DC voltage, check the main power supply rectifier section, not individual drive modules.

Verify power supply input

Check three-phase input voltage at the main cabinet disconnect. Verify all three phases are present and balanced (typically 400-480VAC). Check main circuit breakers and fuses in the power distribution section.

Disconnect main power and follow LOTO procedures before checking fuses or connections in the high-voltage section.

Inspect DC bus capacitors and charging circuit

Examine the DC link capacitors in the power supply section for physical damage, bulging, or leakage. Verify the charging resistor circuit is functioning - DC bus should charge within 2-5 seconds of power-on.

If DC bus charges slowly or fluctuates, measure charging resistor values - they often fail open in older machines.

Review drive module error history

Access Service > Error Messages > Drive Errors to view historical drive faults. Look for recurring over-voltage, under-voltage, or DC bus monitoring errors that may indicate intermittent power supply issues.

Use MOD function 'DRIVE INFO' to display detailed drive module diagnostics including DC bus ripple and voltage history.

Verify encoder communication status

Navigate to Test > Service > Encoder Test. Select the affected axis and check EnDat status - should show 'EnDat OK' or 'Communication Active'. Error messages like 'EnDat Timeout' or 'CRC Error' indicate communication failure.

Press 'Extended Info' soft key in Encoder Test to display detailed EnDat error counters and signal quality indicators.

Inspect EnDat encoder cable

Power down the control and inspect the EnDat cable from encoder to CC/MC drive input. Check for proper shielding connection at both ends, cable damage, tight bends (minimum 10x cable diameter), or contamination at connectors. Clean contacts with contact cleaner if necessary.

Do not disconnect EnDat cables while power is applied - this can damage the encoder electronics.

Check encoder power supply

Using a multimeter, verify encoder supply voltage at the encoder connector (typically +5V or +3.3V depending on encoder type). Measure between pins 1 (+) and 4 (0V) on standard Heidenhain encoder connectors. Voltage should be within ±5% tolerance.

Encoder supply is generated by the drive module - if voltage is absent or low, the drive interface electronics may be damaged.

Verify machine parameter encoder configuration

Access machine parameters and verify encoder type configuration. Check MP100 (axis designation), MP1010 (encoder input assignment), and MP6210 (encoder type). Ensure settings match the physical encoder installed (EnDat01, EnDat02, EnDat22, etc.).

Incorrect encoder type parameter can prevent EnDat initialization even with perfect hardware - verify against encoder label specifications.

Test with backup encoder or swap test

If available, temporarily connect a known-good EnDat encoder to the drive interface to isolate whether the fault is in the encoder head or drive interface. Alternatively, swap encoder cables between axes to determine if the problem follows the cable or remains with the drive.

After encoder swap, power cycle the entire control to force re-initialization of EnDat communication on all channels.