Rexroth IndraDrive HCS Error Code F8078

Rexroth PLC & VFD Major Hardware

Model: IndraDrive HCS | Code: F8078

Applicable Systems
EFC FEX FEI HNC

Symptoms

Speed controller fault. The speed control loop has detected an error condition, typically velocity feedback loss or speed error exceeding the monitoring window.

Possible Causes

  • Speed feedback (encoder) signal intermittent or lost
  • Speed controller gain parameters improperly tuned
  • Mechanical resonance causing speed oscillation
  • Load inertia mismatch beyond controller capability

Troubleshooting Steps

  1. Step 1: Check encoder cable and connections for intermittent signals
    Wiggle test on encoder cable; no signal drops observed on oscilloscope
  2. Step 2: Review speed controller proportional and integral gain settings
    Gains within typical ranges for the motor/load combination
  3. Step 3: Check for mechanical resonance by monitoring speed actual vs setpoint
    No oscillation in speed response during step changes
  4. Step 4: Adjust controller gains or add low-pass filtering if resonance is present
    Smooth speed tracking without overshoot or oscillation

How to Reset

1) Check encoder signal quality. 2) Review controller gains. 3) Check for mechanical issues. 4) Re-tune if needed. 5) Reset fault.

Frequently Asked Questions

  • Q: How do I tune the speed controller?

    Start with manufacturer default gains. Increase proportional gain until slight oscillation, then reduce by 20%. Set integral time constant to 3-5x the motor mechanical time constant.

  • Q: What causes speed controller fault during normal operation?

    Sudden load changes, encoder signal glitches, or mechanical resonance can trigger the speed error monitor. Check for any recent mechanical changes.

Related Rexroth Fault Codes

Source: Rexroth IndraDrive HCS/HMS Fault Code List, Bosch Rexroth AG

Category: PLC & VFD