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What Is the Indramat F878 Fault Code?

May 09, 2025

Indramat’s Legacy in Motion Control

Although Indramat is no longer manufacturing new servomotors and drives, their legacy products—like the ECODRIVE series—remain operational in countless facilities worldwide. These products have consistently delivered outstanding performance and durability when properly installed and maintained.

However, even the most reliable systems can encounter issues over time. When problems arise, Indramat drive controllers help users diagnose the problem by displaying specific fault codes. One such fault code is the F878, associated with the ECODRIVE drive controller. (In systems using MDD, DDC, DKS, or DDS drives, this same issue would display as fault code 78.)

What Does the F878 Fault Code Mean?

Fault Code: F878 – Velocity Loop Error

The F878 error indicates a problem with the velocity loop monitor. In any motion control system, the velocity loop helps monitor and control the difference between the commanded and the actual speed of the motor.

When fault code F878 appears:

  • The drive controller detects a speed deviation that exceeds tolerance.

  • Immediate action is required to prevent system damage or degraded performance.

  • System operation is typically halted until the fault is cleared.

Causes of the F878 Fault Code

The F878 fault is triggered when the deviation between the commanded velocity and the actual measured velocity exceeds 10% of the motor’s maximum velocity. It can also be triggered if the current demand approaches or exceeds the motor’s peak current limit.

Primary causes include:

Cause Description
Incorrect Motor Cable Connection A loose, damaged, or improperly connected motor cable disrupts proper signal transmission.
Defective Feedback Device Issues with the encoder or feedback mechanism distort velocity measurements.
Defective Drive Control Section Problems within the drive’s control electronics can prevent proper velocity regulation.
Incorrect Velocity Loop Parameter Settings Misconfigured control loop parameters can destabilize motor speed regulation, triggering the fault.

How to Correct the F878 Fault Code

Corrective action depends on the root cause:

  1. Check the Motor Cable

    • Inspect connections for looseness, corrosion, or physical damage.

    • Tighten any loose connections or replace faulty cables.

  2. Verify Velocity Loop Parameters

    • Compare current settings to manufacturer specifications.

    • Adjust settings to ensure they fall within the recommended operational parameters.

  3. Inspect the Feedback Device

    • Test the encoder or feedback sensor for functionality.

    • Replace the feedback device if it is defective.

  4. Evaluate the Drive’s Control Section

    • If cable and feedback checks pass, internal drive electronics may be failing.

    • A faulty control section typically requires professional drive repair or full replacement.

Frequently Asked Questions (FAQs)

Can the F878 Fault Code Be Resolved In-House?

  • Yes, if:

    • The issue is with loose or damaged motor cables.

    • The velocity loop parameters are incorrectly set.

    • These fixes can usually be performed by your in-house maintenance team.

  • No, if:

    • The feedback device is defective.

    • The drive’s control electronics are damaged.

    • Professional repair or replacement is recommended to ensure safe and reliable operation.

What Happens if the F878 Fault Is Ignored?

Ignoring this fault can lead to:

  • Increased wear and tear on motor components.

  • Inconsistent system performance.

  • Risk of motor damage or complete drive failure over time.

Prompt diagnosis and action are critical to maintaining system health.

 

For more information , contact PLG Automation:Email: sales@plgautomation.comPhone: 800-906-9271