Urgent! Help with the MSM tool (stuck in Param preload)
If you are seeing Alarm A07991 (often referred to as 0a7991 in hex logs) on your Siemens SINAMICS drive, it is important to know that this is typically a status message rather than a critical system failure. It indicates that the Motor Data Identification (ID) routine has been activated.
This article covers why this alarm occurs and how to resolve it across various Siemens platforms like the SINAMICS G120, G130, and S120. What is Siemens Fault A07991?
The alarm code A07991: Motor data identification activated means the drive is waiting to perform a measurement to learn the electrical characteristics (resistance, inductance, etc.) of the connected motor.
Until this routine is completed or deactivated, the drive will not allow normal operation or parameter saving. It is most common during: Initial Commissioning: When a new motor is being set up.
Maintenance: After a motor or power module has been replaced.
Parameter Changes: When the control mode or motor data has been manually reset. Step-by-Step Solutions to Resolve A07991 1. Perform the Motor Identification (Recommended)
The standard way to clear this alarm is to let the drive finish its measurement.
Step A: Ensure the motor is safe to move (if using rotating measurement) or at a standstill (if using stationary measurement). Step B: Give the drive a "Start" (ON) command.
Step C: The drive will apply current to the motor. You may hear a humming sound. Once the measurement is finished, the drive will automatically switch to "OFF" and the A07991 alarm will disappear.
Step D: Perform a RAM to ROM save (Parameter p0971 = 1) to permanently store the new data. 2. Manually Deactivate the Routine
If you cannot run the identification (e.g., you are testing the drive without a motor connected), you can disable it manually through the parameter list:
Set P1900 = 0: This turns off the motor data identification and rotation test.
Set P1300 = 0: In some cases, changing the control mode to basic V/f control can also bypass the need for precise motor identification. 3. Resolving Persistent Alarms (The A8526 Connection)
Users often see A07991 alongside Alarm A08526 (No cyclic connection). If A07991 won't clear even after a successful ID run:
Check your communication with the PLC. A08526 indicates the PLC is not sending the correct control word (bit 10 must be high).
If no PLC is present, set p2030 = 0 (No protocol) and perform a power cycle. Troubleshooting Tips How can resolve the alarm Code A7991 - Siemens SiePortal
Troubleshooting Siemens Fault 0A7991: A Comprehensive Guide
Are you experiencing issues with your Siemens equipment due to fault code 0A7991? This error code can be frustrating, especially if you're unsure of its meaning or how to resolve it. In this text, we'll provide you with essential information to help you troubleshoot and potentially fix the issue.
What is Siemens Fault 0A7991?
Siemens fault 0A7991 is an error code that appears on Siemens devices, indicating a specific problem. Unfortunately, without more context, it's challenging to pinpoint the exact cause. However, we can guide you through general troubleshooting steps and offer possible solutions.
Possible Causes of Fault 0A7991
Although the exact cause may vary depending on the device, here are some potential reasons for the fault:
Troubleshooting Steps
To resolve the Siemens fault 0A7991, follow these steps:
Additional Tips
If you're still experiencing issues or need more specific guidance, please provide more details about your device, such as the model number or a brief description of the problem. This will help us provide a more tailored solution.
The Siemens A07991 alarm indicates that Motor Data Identification (ID) is currently active or scheduled to run at the next power-on command. This is a standard part of the commissioning process for Siemens SINAMICS drives (such as the G120 or G130) where the inverter measures the connected motor's characteristics to optimize control performance. Core Cause
The drive is waiting to perform a measurement routine. While this alarm is active, the drive typically cannot be started for normal operation until the identification is either completed or intentionally disabled. Primary Solutions
To clear the A07991 alarm, use one of the following methods: Complete the Identification Routine Give the drive a "Run" or "Start" command.
The motor may "whistle" or make noise for a few seconds during stationary measurement without rotating.
Once the measurement is successful, the alarm clears automatically, and the drive transitions to a ready state.
Disable the Identification ManuallyIf you do not wish to run the identification (e.g., during bench testing or Factory Acceptance Tests (FAT)), change these parameters:
P1900 = 0: Set this to "Inhibited" to disable the motor data identification and rotation test.
P1300 = 0: If the fault persists, some users recommend setting the control mode to "V/f standard". siemens fault 0a7991
P0340 = 0: Set this to 0 to remove the requirement for motor details entirely during initial testing. Finalize Configuration (RAM to ROM)
After identification is complete or parameters are changed, save the settings by performing a RAM to ROM copy (set P0971 = 1). This ensures the alarm does not return after a power cycle. Common Troubleshooting Scenarios
A07991 & A08526 Together: If you see both, there is likely a communication issue with the PLC. If no PLC is connected, set P2030 = 0 (No protocol) and perform a RAM to ROM save before restarting.
Persistent Alarm After Power Cycle: If the alarm returns even after you thought it was finished, it likely wasn't saved to permanent memory. Ensure you perform the RAM to ROM save procedure. How can resolve the alarm Code 7991 and 8526 - SiePortal
Fault Report: Siemens Fault 0A7991
Introduction:
The Siemens fault code 0A7991 is a specific error code that indicates a problem with a Siemens device or system. This report aims to provide a detailed overview of the fault, its possible causes, symptoms, and recommended actions for troubleshooting and resolution.
Fault Description:
The Siemens fault code 0A7991 is a hexadecimal code that corresponds to a specific error condition. The code is typically displayed on a Siemens device or system, such as a PLC (Programmable Logic Controller), HMI (Human-Machine Interface), or other Siemens equipment.
Possible Causes:
Based on Siemens documentation and technical support resources, the following are possible causes of fault code 0A7991:
Symptoms:
The symptoms associated with fault code 0A7991 may vary depending on the specific device or system affected. Common symptoms include:
Troubleshooting Steps:
To troubleshoot and resolve fault code 0A7991, follow these steps:
Recommended Actions:
Based on the possible causes and symptoms, the following recommended actions are suggested:
Conclusion:
Fault code 0A7991 is a specific error code that indicates a problem with a Siemens device or system. By understanding the possible causes, symptoms, and troubleshooting steps, users can effectively resolve the fault and restore normal operation. If you are experiencing this fault, it is recommended that you consult Siemens documentation and technical support resources for guidance.
in Siemens SINAMICS drives (such as the G120 or S120) indicates that Motor Data Identification is activated
. This is an alarm rather than a critical fault, signaling that the drive is prepared to measure motor parameters during the next "Power On" or "Run" command. Meaning & Causes Identification Pending
: The drive is waiting for a run signal to perform a standstill or rotating measurement of the connected motor. Commissioning Mode
: It typically appears during initial setup or after changing motor parameters when the drive needs to "learn" the motor's electrical characteristics. Power Cycle Artifact
: It may reappear after a power loss if the identification process was never completed or if the parameters were not saved to permanent memory (RAM to ROM). Solutions to Clear the Alarm
You can resolve this alarm using one of two primary methods through the Siemens SiePortal Complete the Identification Process
Ensure the motor is safe to run (especially if "Rotating Measurement" is selected). Run command
(via PLC or local control). The drive will energize the motor (often making a whistling sound) for several seconds.
Once the measurement finishes, the drive will automatically set parameter p1900 to 0 , and the alarm will vanish.
: Perform a "RAM to ROM" save to ensure the data is kept after the next power cycle. Manually Deactivate the Function
If you do not wish to perform the identification (e.g., during testing with a dummy load), manually set (Inhibited). In some control modes, you may also need to set (V/f control) to bypass advanced motor modeling. step-by-step instructions
for performing a RAM to ROM save on a BOP-2 or via STARTER software? How can resolve the alarm Code 7991 and 8526 - SiePortal
The Siemens alarm code A7991 (or A07991) specifically indicates that "Motor data identification is activated". While there isn't a single formal academic "paper" on this specific routine, it is a standard commissioning procedure documented extensively in Siemens technical manuals and support forums. Summary of Fault A7991
This is an alarm, not a trip fault, meaning the drive is waiting for a command to start the identification process rather than stopping due to an error. If you are seeing Alarm A07991 (often referred
Cause: The parameter P1900 has been set to a value (typically 1 or 2), signaling the drive to perform a motor ID run.
Behavior: The drive will not start normal operation until this identification is completed or disabled.
Common Scenarios: It often appears during initial commissioning or after a power cycle if the ID run was never successfully completed and saved to the permanent memory (ROM). Resolution Steps
Based on Siemens SiePortal documentation and community solutions, you can clear this alarm using one of these methods: Complete the Identification Run: Give the drive a "Start" command.
The motor may rotate slightly or emit a humming sound for about 10–60 seconds while it measures stator resistance and inductance.
Once finished, the alarm will disappear automatically, and P1900 will reset to 0. Manually Disable the Procedure:
If you cannot run the identification (e.g., the motor is connected to a load that cannot move), set P1900 = 0 manually. Permanent Save:
After the alarm clears, perform a "RAM to ROM" copy to ensure the settings are saved and the alarm does not return after a reboot.
For a deep dive into the technical details of the identification process itself, you should refer to the "Commissioning" section of the SINAMICS G120 List Manual or the operating instructions for your specific drive model (e.g., G120, S120, or G130).
Are you seeing this on a new installation or did it appear suddenly on a running machine? Fault A07991 cannot be cleared on SINAMICS G120C drive
The Siemens alarm (commonly appearing on Sinamics drives like the G120 or S120) signifies that Motor Data Identification (Motor ID) is activated
. This is typically not a critical failure but a mandatory safety and performance state where the drive waits for a measurement routine to calibrate itself to the connected motor. Siemens SiePortal Primary Cause and Function
When a drive is first commissioned or its motor parameters are reset, it enters a "standby" mode for identification. Siemens SiePortal The Routine:
The inverter needs to perform a measurement—often at a standstill—which typically involves a "run" command lasting about 10 seconds. During this time, the drive may produce a whistling sound as it identifies stator resistance and other motor characteristics. Automatic Deactivation:
Once the identification run is successfully completed, the alarm should disappear automatically, and the drive transitions into its normal operating state. Siemens SiePortal Troubleshooting and Resolution Strategies
If the alarm persists or prevents operation, technical specialists on the Siemens SiePortal suggest several remedies: Perform the Motor ID Run:
Carry out the standstill measurement by issuing a "run" command. Ensure the configuration is complete and save the settings from RAM to ROM once finished. Manual Inhibition:
If an identification run is not possible (e.g., during a Factory Acceptance Test without the final motor), you can set parameter to inhibit the motor identification feature. Address Communication Blocks:
In some cases, the A07991 alarm appears alongside communication errors like A08526. If the drive is controlled by a PLC, ensure the network connection (Profinet/Profibus) is active and sending the correct control bits. Factory Reset:
If the alarm cannot be cleared through standard parameter changes, performing a factory reset and reconfiguring basic settings may be necessary to clear the drive's internal state. Siemens SiePortal Operational Impact The most significant impact of A07991 is that it typically prevents the drive from starting
until the identification requirement is satisfied. In industrial transport systems, this can cause "timeout" errors or crashes if the system expects immediate movement while the drive is still in its 10-second calibration phase. Siemens SiePortal Alarms A 7991 and A8526 - SiePortal - Siemens
While there is no official Siemens documentation for a fault code exactly matching "0a7991," the code likely refers to Alarm A7991, which typically indicates that a motor identification (motor ID) has not yet been performed or completed during commissioning. Understanding Alarm A7991
In Siemens SINAMICS drive systems, this alarm serves as a warning that the drive requires data identification to optimize its mathematical model of the connected motor. Until this is performed, the drive may not operate or may operate with reduced performance. Recommended Troubleshooting Steps
To resolve this alarm, users on Siemens SiePortal suggest the following:
Complete the Configuration: Ensure all motor parameters (rated voltage, current, power, speed, etc.) have been correctly entered in the commissioning software. Perform Motor Identification:
Navigate to the commissioning folder in your software (e.g., TIA Portal or STARTER). Select and trigger Motor Identification at standstill.
Give the drive a "Run" command to start the identification process. The motor will not rotate but will be energized with a high-frequency signal to measure its electrical characteristics.
Save Parameters: Once the identification is complete, perform a RAM to ROM copy to ensure the new parameters are saved permanently to the drive's non-volatile memory. Related Faults to Check
If the code persists or is accompanied by other errors, consider these related Siemens drive faults: F7900: Motor blocked or speed controller at its limits.
F7902: Motor stalled, often due to a lack of static optimization.
A8526: No connection to the PLC/controller, often a communication or configuration issue.
If you are using a specific software like TIA Portal, you can check the full Alarm History by connecting your PC to the drive to view the exact timestamp and detailed description of the event.
Are you currently in the commissioning phase of a new drive, or did this fault appear on a system that was already running? Communication error : Issues with data transmission or
How can resolve the alarm Code 7991 and 8526 - SiePortal - Siemens
The code A7991 (often appearing in logs as part of a longer string like 0a7991) is a Siemens drive alarm indicating that the motor identification has not yet been performed or completed. This typically occurs during the initial commissioning phase of a SINAMICS drive. Recommended Fixes
According to expert contributors on the Siemens SiePortal, you can resolve this by following these steps:
Complete the Configuration: Ensure all hardware and motor parameters are correctly entered in the configuration. Run Motor Identification: Navigate to the commissioning folder.
Perform a "Motor Identification at Standstill" (p1910). This allows the drive to measure the electrical characteristics of the motor.
Save Parameters: Once the identification is successful, perform a "RAM to ROM" copy to ensure the data is saved permanently to the drive's memory. Related Faults to Check
If you are seeing other codes alongside A7991, they may point to hardware or setup issues: F07900: Motor Blocked or Speed Controller at its limits.
F7901: Motor overspeed, often caused by a faulty encoder or incorrect wiring. If you'd like, let me know: The specific Siemens drive model (e.g., S120, G120) If this happened during initial setup or during operation Any other fault codes currently appearing on the display
How can resolve the alarm Code 7991 and 8526 - SiePortal - Siemens
p1520, p1521) is clamped below what the load requires during acceleration..x170 file (Drive Control Chart) or a *.pz2 backup to a network drive. After any tuning, compare with baseline.Insufficient power to a remote I/O station (e.g., ET 200M) can cause modules to power cycle, leading to startup errors that manifest as 0A7991.
Siemens fault 0A7991 is not a mysterious error to dread—it is a precise diagnostic tool. By understanding that it signals either a mechanical obstruction, a fluid dynamics issue (vapor lock), or a parameter mismatch, you can move from reactive fault-resetting to proactive engineering.
The golden rules for conquering 0A7991:
p2177 and p2178 to your specific load inertia and process cycle.With this guide, you now have the knowledge to systematically diagnose, resolve, and prevent Siemens fault code 0A7991, minimizing downtime and protecting your valuable equipment.
Need further support? Visit the Siemens Industry Online Support (SIOS) portal and search for FAQ ID: 109479877 / Fault Code 0A7991.
The Siemens fault code A07991 (often searched as 0a7991) specifically indicates that Motor Data Identification is activated. This is not a critical equipment failure but rather a status alarm triggered during the commissioning or configuration phase of Siemens SINAMICS drives, such as the G120, G120C, and G150 series. Understanding Alarm A07991
When this code appears, the drive is notifying you that a motor identification routine has been scheduled or is currently running. This routine is essential for the inverter to learn the electrical characteristics of the connected motor (such as resistance and inductance) to ensure precise control.
Behavior: The alarm typically disappears automatically once the identification routine completes successfully.
Restriction: While this alarm is active—especially if a rotating measurement is selected—you may be unable to save parameter assignments to the ROM until the process finishes. Common Troubleshooting Steps
If the alarm does not disappear or prevents the drive from running, use the following methods to resolve it: 1. Complete the Identification Routine
The most direct fix is to allow the drive to perform the check.
Apply a power-on command (start signal) to initiate the routine.
Ensure the motor is safe to move if a "Rotating Measurement" was selected. Once finished, the alarm will clear itself. 2. Manually Disable the Routine
If you do not wish to perform the identification (e.g., during bench testing without a motor), you can disable it via the Siemens Parameter List:
Set p1900 = 0 (Motor data identification and rotation test: Disabled).
Set p1300 = 0 (Control mode: V/f standard) if advanced vector control isn't needed immediately. 3. Resolving Persistent Alarms (A07991 + A8526)
This alarm frequently appears alongside A8526, which indicates a communication timeout with a PLC.
Check Connections: Ensure the Profinet/Profibus cable is securely plugged in and the PLC is powered on.
No PLC Connection: If testing the drive standalone, set p2030 = 0 (No protocol) and perform a "RAM to ROM" save. Technical Summary Table Default/Action Description p1900 Set to 0 Disables the motor identification routine. p0971 Set to 1
Saves parameters from RAM to ROM (perform after clearing alarm). p0340 Set to 0
Removes the requirement for motor details for initial testing.
If you are performing a Factory Acceptance Test (FAT) without the final motor, attaching a smaller spare motor can sometimes bypass identification faults by providing enough feedback for the drive to initialize. Alarms A 7991 and A8526 - SiePortal - Siemens
Either the network connection (profibus/profinet?) between the PLC controlling the drive is powered off, network connection lost ( Siemens SiePortal How can resolve the alarm Code A7991 - SiePortal - Siemens