What Is the Indramat F401 Error Code?

Indramat drive controllers, long valued for their durability, performance, and reliability, are still found in motion control systems across the globe. Despite the company's closure following its acquisition by Bosch Rexroth, Indramat products continue to power critical industrial equipment. Like any electronic system, however, they are not immune to faults especially after decades of use. One such issue users may encounter is the F401 error code.

What Does the F401 Error Code Mean?

The F401 fault code on an Indramat drive controller is classified as a Double MST Error Shutdown. MST stands for Master-Sync-Telegram a key component of the SERCOS communication protocol. This error occurs when the drive fails to receive the master-sync telegram signal in two consecutive SERCOS cycles, triggering a system shutdown to protect the equipment.

The H1 status display on the controller alternates between F4 and 01 to indicate this fault.

Causes of the F401 Fault Code

Three common issues can lead to the F401 error:

1. Fiber Optic Cable Interruption

   • Loose or damaged fiber optic cables in the SERCOS ring

2. High Light Signal Attenuation

   • Excessive signal loss (more than 12.5 dB) between the transmitter and receiver

3. Faulty or Improperly Seated SERCOS Interface

   • A malfunctioning interface or one not fully seated in its backplane slot

These faults disrupt communication between the drive controller and other system components, making immediate troubleshooting essential.

FAQs

 How Do You Fix the F401 Error Code?

To resolve the F401 error, follow these steps:

• Check Fiber Optic Connections
  Ensure that all fiber optic cables in the SERCOS ring are securely and correctly connected.

• Test with Spare Cables
  If connections appear fine, replace the fiber optic cables temporarily to test whether damaged cables are causing the fault.

• Measure Light Signal Attenuation
  Use a light meter to measure the attenuation between transmitter and receiver. If it's above 12.5 dB, signal quality is insufficient and adjustments or replacements are needed.

• Inspect the SERCOS Interface
  Make sure the SERCOS interface is fully seated. If problems persist, try replacing it with a known working interface module.

 Can the F401 Fault Be Resolved In-House?

Yes partially.
In-house teams can usually:

• Inspect and replace fiber optic cables

• Reseat or swap the SERCOS interface

However, more complex diagnostics or component-level repairs  if the issue lies within the drive controller itself) should be handled by professionals. Attempting in-house repairs without expertise can risk further damage.

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