Applicable Systems
EFC
FEX
FEI
HNC
Symptoms
The drive reports E2074 indicating the drive module temperature exceeds the limit or the current detection circuit is abnormal. The equipment trips within minutes of startup, often accompanied by cooling fan noise or fan stoppage.
Possible Causes
- Encoder cable shielding damage causing signal interference
- Encoder internal component failure (optical disc contamination, photosensor aging, chip damage)
- Drive power module IGBT aging causing false current detection
- Incorrect encoder type or parameter settings in the drive configuration
- Insufficient cooling or blocked airflow causing thermal trip
Troubleshooting Steps
- Step 1: Inspect encoder cable for physical damage, check shielding continuity and grounding
Cable intact, shielding properly grounded at both ends - Step 2: Use oscilloscope to measure encoder feedback signal waveforms (A/B phases should be clean square waves with 90 degree phase offset)
Clean square wave signals with correct phase relationship - Step 3: Check drive encoder type setting matches actual encoder (incremental vs absolute)
Encoder type parameter matches the physical encoder - Step 4: For thermal faults (E2074): clean heatsink, check fan operation, measure three-phase current balance
Fan operational, heatsink clean, current balance within 5% - Step 5: If signal issues persist after cable and parameter checks, replace encoder or drive module
Fault clears after component replacement
How to Reset
To reset: 1) Fix the root cause (encoder cable, signal interference, cooling, or parameter error). 2) Clear the fault via HMI or parameter interface. 3) Restart the drive. For auto-compensation faults (F8010-F8016), re-run the auto-tuning procedure after fixing the issue. Caution: Repeated trips without fixing the root cause will permanently damage drive components.
Frequently Asked Questions
- Q: What causes Rexroth drive fault E2074?
Drive Module Overheating / Current Detection Anomaly. The drive reports E2074 indicating the drive module temperature exceeds the limit or the current detection circuit is abnormal. The equipment trips within minutes of startup, often accompanied by cooling fan noise or fan stoppage.
- Q: How do I test the encoder signal on a Rexroth drive?
Use an oscilloscope to measure the encoder feedback signals. For incremental encoders, A and B phases should show clean square waves with 90 degree phase offset, and frequency should vary with motor speed. For absolute encoders, check the battery voltage and serial communication signal.
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Source: Bosch Rexroth IndraDrive Manual; baijiahao.baidu.com (Rexroth servo drive fault codes); szsfwx.com; 11467.com; chem17.com; oil-gift.com
Category: PLC & VFD
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