How to Fix Siemens SINAMICS Alarm A7994 Motor ID Active?

Seeing A7994 on your Siemens drive? This alarm means Motor Data Identification is active. Learn how to complete the ID run and clear the code today.

 

Solving Siemens Alarm A7994: Why "Motor Data ID" is Active

If you are looking at your Siemens SINAMICS drive and the display is flashing A7994, your drive is currently in a "learning" mode. In the Siemens manual, this is defined as "Motor data identification active."

This is a very common sight during the commissioning of a new drive or after changing motor parameters. It isn't a fault that stops the drive; it’s a notification that the drive is prepared to perform an Auto-tune or Identification Run to measure the motor's electrical characteristics. Let's look at how to complete the process and get the alarm to disappear.

Why is Alarm A7994 Appearing?

The A7994 alarm triggers whenever Parameter P1900 is set to something other than 0. The drive is essentially "on standby," waiting for a start command so it can send pulses to the motor to measure stator resistance, leakage inductance, and flux.

Common triggers include:

• Initial Setup: You just finished the commissioning wizard, and the drive is ready to tune.
• Manual Request: Someone set P1900 to 1 (Identification at standstill) or 2 (Identification with rotation).
• Parameter Changes: You changed the motor nameplate data (Group P0300), and the drive automatically reset the ID run request.

Step-by-Step: How to Resolve A7994

1. Give it the "Start" Command

The most common reason A7994 stays on the screen is that the drive is waiting for a human to tell it to start the test.

• Ensure the motor area is clear and safe.
• Press the Hand/Auto button to go to local control (if using a BOP-2).
• Press the Green Start Button.
• The motor might make a high-pitched humming sound. This is normal. The drive is measuring the windings.

2. Wait for Completion

Once you hit start, the drive will begin the measurement.

• The alarm A7994 will stay active during the test.
• Do not interrupt the power or stop the drive manually unless there is an emergency.
• When the measurement is finished, P1900 will automatically reset to 0, and the A7994 alarm will disappear.

3. Check Parameter P1900

If you didn't mean to start an ID run and you want the alarm to go away without tuning:

• Go to Parameter P1900.
• Set the value to 0 (Inhibit/Disable).
• The alarm will clear instantly, but keep in mind that your motor performance might not be optimized if the drive hasn't learned the motor data.

4. Verify Safe Torque Off (STO)

If you press "Start" and the drive doesn't do anything, check your STO terminals. If the safety circuit is open, the drive cannot perform the ID run, and A7994 will just sit there flashing indefinitely.

What if A7994 turns into a Fault (F07990)?

If you start the ID run and the drive trips with a Fault F07990, it means the identification failed. This usually happens because:

• The motor is not connected.
• An output isolator switch is open.
• The motor data you entered (P0304-P0311) doesn't match the physical motor.

Summary

The Siemens A7994 alarm is your friend. It’s the drive’s way of saying, "I'm ready to optimize the motor, just give me the signal!" Simply press the Start button to allow the drive to finish its measurements. Once it learns the motor, the alarm clears, and your drive will run much more efficiently.