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Siemens alarm

25000 Hardware Fault Active Encoder

The encoder the axis is using for position has a hardware problem: signal lost, cable fault or a failed encoder.

Stops the machineSiemens SINUMERIK 840D sl, 828D and 840D powerline

What it means

The encoder the axis is using for position has a hardware problem: signal lost, cable fault or a failed encoder.

Common causes

  • Damaged encoder cable
  • Coolant in a connector
  • Failed motor encoder or scale

What to check first

  1. Note the axis
  2. Check the cable and connectors

Lock out the machine before reaching into it. Never bypass a door switch or interlock to clear an alarm.

When to call a repair tech

Encoder and cable replacement needs a tech, and the axis reference may need setting again.

Repair companies that work on Siemens

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Quick answers

What does Siemens alarm 25000 mean?

The encoder the axis is using for position has a hardware problem: signal lost, cable fault or a failed encoder.

What causes Siemens alarm 25000?

Damaged encoder cable. Coolant in a connector. Failed motor encoder or scale.

How do I fix Siemens alarm 25000?

Note the axis. Check the cable and connectors. Encoder and cable replacement needs a tech, and the axis reference may need setting again.

Alarm numbers and text can differ by control model, software version and machine builder. This page is a starting point from people who have worked on these machines, not a replacement for your machine builder's manual.

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