How to Fix Siemens SINAMICS Alarm A7991 Motor ID Selected?

Seeing A7991 on your Siemens drive? This alarm means Motor Data Identification is selected. Learn how to start the ID run or clear the alarm in our guide.

 

Solving Siemens Alarm A7991: Motor Data Identification Selected

If you are looking at your Siemens SINAMICS G120 or S120 drive and the display is flashing A7991, you are in the final stages of setting up your motor. In the Siemens manual, this is defined as "Motor data identification selected."

This isn't a "broken" state. It is the drive's way of saying, "I'm ready to measure the motor's electrical traits, but I'm waiting for you to tell me when to start." Let's look at why this appears and how to clear it so you can get back to production.

Why is Alarm A7991 Appearing?

The A7991 alarm is triggered when Parameter P1900 (Motor data identification and speed controller optimization) is set to a value other than 0.

Typically, this happens because:

• New Setup: You just finished the basic commissioning wizard.
• Manual Selection: A technician set P1900 to 1 (Standstill ID) or 2 (Rotating ID).
• Parameter Change: You adjusted motor nameplate data (Group P0300), and the drive automatically decided it needs a new ID run to remain accurate.

How to Resolve Alarm A7991

1. Perform the Identification Run (Recommended)

The best way to clear A7991 is to let the drive finish what it started. To do this, you must give the drive a Start Command.

• Ensure the motor area is clear and safe.
• On your BOP-2 (Basic Operator Panel), press the Hand/Auto button to enter Hand mode.
• Press the Green Start Button.
• The alarm A7991 will switch to A7994 (Identification active). The motor might hum or rotate slightly.
• Once the measurement is done, the drive will stop, P1900 will return to 0, and all ID alarms will disappear.

2. Cancel the ID Run

If you don't want to perform the ID run right now and you want the alarm to go away:

• Navigate to Parameter P1900.
• Change the value to 0 (Inhibit).
• The alarm will clear instantly. (Note: Your motor performance might not be as smooth if the drive hasn't "learned" the motor's resistance and inductance).

3. Check for Start Inhibits

If you are pressing the Start button but the ID run won't begin (and A7991 keeps flashing), check your Safe Torque Off (STO) terminals. If the safety circuit is open, the drive cannot apply power to the motor, and the ID run will stay "selected" but never start.

A7991 vs. A7994: What's the difference?

Technicians often confuse these two:

• A7991: Identification is Selected. The drive is waiting for you to press Start.
• A7994: Identification is Active. The drive is currently sending electricity to the motor to measure it.

Summary

The Siemens A7991 alarm is just a "Ready" signal. It’s the drive asking for permission to tune the motor. To clear it, simply provide a Start command or set P1900 to 0. For the best motor life and efficiency, we always recommend completing the ID run.