BACnet CRC Error
CRC (Cyclic Redundancy Check) errors indicate that a received BACnet frame was corrupted in transit. The checksum does not match, and the frame is discarded. Common on MS/TP over RS-485.
Common Causes
- Electrical noise or EMI on RS-485 wiring
- Voltage drop or marginal signal levels on long trunks
- Improper termination causing reflections and bit errors
- Ground loops or shield grounding issues
Fix Steps
- Verify RS-485 differential voltage (A–B) and wiring integrity.
- Add or correct 120 Ω termination at both ends of the trunk.
- Route cable away from motors, VFDs, and high-current AC.
- Fix shield grounding: single-point ground, avoid ground loops.
- Use twisted-pair cable; consider shielded if noise persists.