What Is the Indramat 78 Error Code?

Indramat motion control systems are widely recognized for their performance, reliability, and longevity. Although the original Indramat brand is now defunct, its legacy products especially drive controllers like the DDC, DDS, DKS, and MDD series are still in use across many industrial environments. One common issue that operators may encounter with these systems is the 78 error code.

This two digit fault code is displayed on the H1 status indicator of older Indramat drive controllers such as the DKS or DDS. Unlike the four digit F878 error used in ECODRIVE systems, the 78 error code represents the same issue a velocity loop error in a simplified format.

What Does Error Code 78 Mean?

Error code 78 is triggered when there’s a mismatch between the velocity command and feedback signal within the servo system. If the deviation between these two values exceeds 10% of the motor’s maximum speed and is not corrected within 10 milliseconds, the system registers a failure. This situation results in the drive controller shutting down to protect the equipment.

The controller cannot recognize or process a movement command when the actual motor behavior doesn't align with expected motion. This loss of synchronization disrupts the servo loop and indicates a critical fault that must be resolved before normal operations can resume.

Causes of the Indramat 78 Error Code

Several issues can cause the feedback signal to fail in correcting itself quickly enough, leading to the 78 error code:

• Loose or improperly connected motor cable

• Defective motor cable

• Faulty feedback device (encoder or resolver)

• Incorrectly configured velocity loop parameters

• Damaged or malfunctioning power section of the drive controller

How to Fix the 78 Error Code

Troubleshooting this error requires a systematic check of the motor and its connections:

1. Inspect the Motor Cable

   • Ensure the cable is securely connected at both ends.

   • If the cable is damaged, replace it with a new, manufacturer-approved cable.

2. Verify Velocity Loop Parameters

   • Refer to the drive manual to ensure the parameters for the velocity loop are correctly configured.

   • Re-tune or reset the parameters if necessary.

3. Check the Feedback Device

   • If the encoder or resolver is faulty, you may receive incorrect speed feedback.

   • Consider testing or replacing the feedback device if the problem persists.

4. Evaluate the Drive Controller

   • If all other components are working properly, the issue may lie within the drive’s power section.

   • In this case, the drive controller itself may need to be repaired or replaced.

Can the 78 Error Be Resolved In-House?

Yes if the issue is minor, such as:

• A loose cable connection

• Incorrect parameter settings

These problems can typically be handled by in-house maintenance teams. However, more serious failures  a defective power section or faulty motor feedback should be left to professionals experienced with legacy Indramat hardware.

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