Category: schneider

The ATV71 inverter displays a message at the top of the screen stating “Last fault occurred Brake control,” with status words listed below (ETA state word 0037 Hex, ETI state word 8812 Hex, Cmd word 000F Hex). This indicates that the last fault was related to brake control. Based on the documentation, we determine that this corresponds to fault codes “brF” or “bLF,” which are typical indicators of feedback anomalies or release failures detected by the brake controller.

I. Fault Meaning and English Title

In the manufacturer’s documentation, such faults are referred to as “Brake feedback fault” or “Brake control fault.” The Chinese translations are often “Mechanical brake feedback fault” or “Brake control fault.”

• sl1: When the brake feedback contact signal does not match the internal logic of the inverter, a brF error is immediately triggered.
• sl2: When incorrect parameter settings or improper brake current and logic control prevent the brake from releasing correctly, this fault is also indicated.

II. Main Causes of the Fault

1. Abnormal Brake Feedback Contact Status

The internal logic expects the electromagnetic brake to be in a certain state (open or closed), but the actual feedback does not match, leading to the assumption that the brake has not been released or closed, thus triggering the fault.

2. Insufficient Brake Release Current / Improper Parameter Settings

Parameters Ibr (forward) and Ird (reverse) represent the brake release current thresholds. If these are set too low, they may not provide enough energy to the brake (controlled via GPIO), preventing it from releasing.

3. Unreasonable Brake Release Time Settings

Parameters bEn (brake closing frequency/logic control related) and bEt (brake release time), if not set or set unreasonably, can cause the inverter to mistakenly believe that the brake has failed to release and trigger a fault.

4. Brake Mechanical or Feedback Unit Fault

Brake bushing wear, spring fatigue, coil disconnection, feedback switch disconnection, or loose wiring can all cause inconsistencies between the mechanical state and the logic.

5. Brake Unit Electrical Short Circuit (bUF Error)

Although not identical to brF, a short circuit in the brake unit can also trigger a logic-based brake failure.

III. Manufacturer’s Official Setting Recommendations

1. Enable Brake Logic Parameters in Expert Mode
   • Parameter brH b2: If set to “1,” feedback contact confirmation is included in the brake release logic; if set to “0,” only the preset time is relied upon.
   • Parameter bEt (Brake Engage/Release Time): Set to a value not less than the actual inertial closing time required by the brake. For example, if the actual time is approximately 1s, set it to at least 1s or more. Otherwise, a fault will be认定 (determined) if the feedback does not close within the time limit.
2. Calibrate Brake Release Current Parameters
   • Adjust Ibr and Ird to ensure they provide sufficient current to fully release the brake.
3. Check Feedback Logic
   • Verify that the feedback contacts are correctly connected to the digital inputs, the control logic is properly assigned, and the wiring is correct.

IV. Comprehensive Fault Troubleshooting Process

Based on the above information, the following systematic process is summarized:

✅ Step 1: Reset and Confirm Fault Recurrence

• Power off and reset or click STOP/RESET, then run again to see if the fault clears or recurs.

🛠 Step 2: Check Brake Circuit and Feedback Wiring

• After powering off, use a multimeter to measure the coil and feedback switch, confirming that the wiring is tight, the cables are undamaged, and there are no short circuits or open circuits.

⚙️ Step 3: Observe Brake Mechanical Status

• Manually operate the brake to detect any sticking, wear, or spring failure. If abnormalities are found, repair or replace as necessary.

🔧 Step 4: Adjust Inverter Parameters

• Enter Expert mode and adjust the following parameters sequentially:
  • brH b2 = 1 (Enable feedback logic)
  • bEt ≥ Actual brake release time
  • Ibr, Ird to sufficient release current
  • If bEn has an “automatic” mode, enable it; if controlling manually, disable it to avoid conflicts.

💡 Step 5: Monitor Operating Status

• After setting the parameters, observe the brake action response time to the inverter, feedback status, and status words to confirm that no further brF faults are reported.

🧩 Step 6: Fault Logging and Duty Strategy

• Summarize experiences, regularly inspect the brake and feedback components, establish maintenance norms, and perform regular resets and checks.

V. Developer and Engineering Recommendations

• If a third-party brake unit is used instead of a Schneider original, be sure to disable the internal cam cable control logic of the brake and fully outsource the control and feedback loops to the third-party system to avoid brF faults.
• Reasonably set automatic restart parameters (e.g., blF, obF may be set to Atr-) to allow automatic reset after the fault disappears, but a conservative mode is recommended to avoid restarting before the brake is released, which could cause injury or mechanical impact.
• Key on-site recommendation: Configure an alarm linkage strategy to monitor the BCA (brake contact alarm) and BSA (brake speed alarm) in the status words and promptly反馈 (feedback) abnormal states.

VI. Conclusion and Recommendations

Aspect	Recommendation
Parameter Settings	In Expert mode, correctly set key parameters such as brH b2, bEt, Ibr, Ird.
Hardware Inspection	Inspect the brake mechanical status, coil, feedback switch, and wiring together.
Process Strategy	Clarify the maintenance boundaries between electrical control and mechanical feedback logic to avoid internal and external conflicts.
Maintenance System	Establish a regular inspection system, save fault records, and ensure long-term safe operation.

🔚 Conclusion

Brake control faults (brF / bLF) in the ATV71 series are often caused by a lack of synchronization between logic and actual actions. By adopting a three-pronged approach of hardware detection, feedback verification, and parameter tuning, the root cause of the fault can be effectively located. After enabling Expert parameters, the inverter will intelligently distinguish between brake action time and feedback contact response, avoiding false alarms and improving system stability. It is hoped that the systematic analysis and references provided in this article will offer practical assistance in resolving brake system issues and ensuring reliable equipment operation.

If you still have questions or require further diagnosis, you can consult the official user manual or contact Schneider’s after-sales technical support for rapid assistance.

1. Introduction: Symptoms and Background

In Schneider Electric’s Altivar ATV310 variable frequency drive (VFD), users may occasionally encounter the code --06 displayed on the integrated 7-segment LED screen. This condition is often accompanied by the motor being unable to start or respond to frequency commands. Although this may look like a fault, --06 is not an error code, but rather a status indication representing a special operating condition—usually “Freewheel Stop.”

This article explains the meaning of --06, identifies common causes, and walks you through practical steps to resolve the issue and restore normal operation.

2. What Does --06 Mean?

The display code --06 on the ATV310 is an operational status code indicating that the drive is currently in Freewheel Stop mode, meaning output is disabled and the motor is freely coasting. This state is not caused by a fault but is often the result of control logic, input conditions, or communication states.

Other common drive statuses include:

• --00: Drive ready (no run command)
• --01: Fast stop
• --06: Freewheel stop

While the drive is in --06, no output frequency is generated—even if run commands are issued—until the condition is cleared.

---

3. Common Causes of --06 Status

Several typical reasons could trigger the --06 state:

🟠 a. Logic Input Assigned to Freewheel Stop

If a digital input (e.g., LI1–LI4) is assigned to the Freewheel Stop function and is active, the drive will enter --06.

🟠 b. Incorrect Run Command in 2-Wire or 3-Wire Mode

• In 2-wire mode (P201 = 2C), the drive needs a level-type run signal on LI1.
• In 3-wire mode (P201 = 3C), a pulse-style start and stop logic is used.
  If wiring or configuration mismatches occur, the drive may fall into --06.

🟠 c. Serial Communication Without Proper Commands

If you’re controlling the drive via Modbus or RS-485, and the master does not send a valid start command (bit 0x6 = 1), the drive enters --06.

🟠 d. Analog Input Loss or Signal Drop

When using 4–20 mA input for speed control, a loss of input signal could trigger a fallback to freewheel stop.

🟠 e. Stop Button or Remote Stop Triggered

If the STOP key on the panel or an external STOP command is active, the drive may enter --06.

🟠 f. Residual State After Power Cycle

Sometimes the drive reboots directly into --06 if the prior control signals remain unchanged.

---

4. Step-by-Step Troubleshooting and Recovery

✅ Step 1: Check Control Mode and Logic Inputs

• Confirm the control mode: P201 (2-wire/3-wire/serial).
• Check P202, P203 for proper assignment of RUN/STOP logic inputs.
• Use monitor mode (parameters 800–811) to observe input signal status.

✅ Step 2: Inspect Physical Inputs

• Check if any logic inputs (e.g., LI1) are incorrectly triggered.
• Look for short circuits, faulty switches, or wiring issues.

✅ Step 3: Check Analog/Serial Communication Settings

• For analog control, verify AI1 input signal and scaling.
• For Modbus, confirm that the master is sending the appropriate control word (bit 0x6 = 1).

✅ Step 4: Clear the Freewheel Stop and Restart

Option 1: Via Panel Navigation

• Press ESC or MODE on the HMI.
• Exit back to the main screen, wait for rdY (ready) to appear.

Option 2: Power Cycle

• Power off the drive for 10 seconds, then power it back on.
• The screen should return to --00 or rdY.

Option 3: Reassign Input Functions

• Use P202 to change logic input function from Freewheel Stop to an unused input.
• Set unused inputs to No Function (typically code 00).

---

5. Ensuring Stable Operation After Recovery

After returning to normal status, take the following steps to avoid future issues:

• ✅ Reassign logic inputs only when needed.
• ✅ Avoid assigning STOP or Freewheel functions to frequently active lines.
• ✅ Add debounce and safety logic in PLC/HMI control.
• ✅ Enable fault auto-restart (parameter 602.0 = 01).
• ✅ Use clear feedback loops if controlling via communication protocol.

---

6. Summary Table

Step	Description
Identification	--06 is Freewheel Stop, not a fault
Analysis	Check logic input functions, run mode, communication
Resolution	Navigate panel, correct wiring or reset power
Optimization	Adjust input definitions and enable self-recovery logic

7. Conclusion

The --06 display on a Schneider ATV310 is a common condition that can interrupt motor operation but is not an error. With proper diagnosis—by inspecting control signals, input assignments, or communication—this state can be quickly cleared.

Once resolved, implementing preventive logic configuration and enabling smart restart strategies can ensure robust and continuous drive performance in both standalone and automated systems.

If issues persist, contacting Schneider’s technical support or reviewing the full parameter manual is recommended.

Introduction

Variable frequency drives (VFDs) are critical components in modern industrial automation systems, widely used in motor control applications to achieve precise speed and torque regulation, enabling efficient production, energy savings, and extended equipment lifespan. Schneider Electric, a globally renowned electrical equipment manufacturer, offers the ATV340 series VFDs, which are known for their superior performance, high reliability, and versatile features. These drives excel in industrial applications requiring high dynamic response and precise control, such as cranes, conveyor systems, and processing machinery.

However, in practical applications, the ATV340 VFD may encounter various faults, one of which is the “Load Movement Error” (fault codes [nLdCF] or [MDCF]). This fault can disrupt production processes, potentially cause equipment damage, or pose safety risks, making timely identification and resolution essential. This document provides a detailed analysis of this fault, covering its definition, causes, diagnostic methods, solutions, and preventive measures to assist users in effectively addressing the issue.

---

Fault Description

The “Load Movement Error” occurs when the load (i.e., the mechanical component driven by the motor) moves unexpectedly without any motion command. On the ATV340 VFD’s display, this fault is typically indicated as “Load Movement Error” or the code “nLdCF,” and it may also appear as “0050Hex” in hexadecimal format. According to the Schneider ATV340 programming manual, this error indicates that the system has detected abnormal load behavior during a stopped or uncontrolled state.

Fault Symptoms

• Display Indication: The VFD displays “Load Movement Error” or “nLdCF” and enters a fault protection state.
• Motor Behavior: The motor may rotate unexpectedly when not commanded, or the load may shift after the motor stops.
• System Impact: The VFD ceases output, preventing normal motor operation, which may lead to production interruptions.

This fault is particularly critical in applications like cranes or hoists, as unexpected load movement could result in dropped cargo, equipment damage, or safety hazards for on-site personnel.

---

Fault Cause Analysis

The “Load Movement Error” can stem from various factors. The following are common causes based on the ATV340 programming manual and practical application experience:

1. Brake System Issues

• Brake Command Circuit Problems: Loose wiring, poor contact, or damaged components in the brake command circuit may prevent proper transmission of brake signals, causing the brake to fail.
• Brake Failure: Mechanical wear, improper adjustment, or aging of the brake itself may result in insufficient braking force, failing to prevent load movement.

2. Incorrect Parameter Settings

• Load Movement Detection Parameters: The ATV340 supports load movement detection through parameters [BRH b5] and torque threshold reference [TTR]. If [BRH b5] is not enabled (default is NO) or [TTR] is set inappropriately, it may lead to missed or false detections.
• Mismatched Motor Control Type: If the parameter [CTT] (motor control type) is not set correctly to [FVC] (standard for asynchronous motors) or [FSY] (standard for synchronous motors), it may cause control instability, leading to abnormal load movement.
• Insufficient Load Holding Time: If the parameter [MD FT] (load holding time) is set too short, the system may fail to detect load status properly after power restoration, triggering the error.

3. Mechanical System Issues

• Loose Transmission Components: Loose or damaged couplings, gears, or belts may allow the load to move even when the motor is stopped.
• Unstable Load Fixation: In hoisting applications, an unstable load center of gravity or faulty securing mechanisms may cause movement due to gravity.

4. Electrical System Issues

• Unstable Power Supply: Voltage fluctuations or momentary power interruptions may disrupt the VFD’s normal control, leading to load instability.
• Electromagnetic Interference: Strong electromagnetic interference on-site may affect the VFD’s signal processing, causing erroneous actions.

5. External Factors

• External Forces: Forces such as wind, gravity, or other external influences acting on the load may cause movement when the motor is stopped.

---

Fault Diagnosis Methods

To accurately identify the cause of the “Load Movement Error,” users can follow these systematic diagnostic steps:

1. Review Fault Information

• Check Display: Note the fault code (e.g., “nLdCF” or “0050Hex”) and the “Latest Error 1 Status” on the VFD display.
• Access Fault History: Use programming software or an HMI to review the fault occurrence time and frequency to analyze triggering conditions.

2. Inspect Brake System

• Brake Command Circuit: Use a multimeter to test the continuity of the circuit wiring and verify the functionality of relays or contactors.
• Brake Condition: Manually check the brake’s engagement and release to ensure its mechanical performance is intact.

3. Verify Parameter Configuration

• Load Movement Detection: Access the parameter menu and confirm if [BRH b5] is set to “YES” (enabled). If set to “NO,” the detection function is disabled.
• Motor Control Type: Ensure the [CTT] parameter matches the motor type ([FVC] for asynchronous motors, [FSY] for synchronous motors).
• Load Holding Time: Check the [MD FT] setting, which defaults to 1 minute. Adjust it to 1–60 minutes based on application needs.

4. Inspect Mechanical System

• Transmission Components: Check for looseness or wear in couplings, gears, or other components.
• Load Fixation: Ensure the load is securely fixed in the stopped state and not subject to external forces.

5. Monitor Electrical Environment

• Power Quality: Use a voltmeter to monitor input voltage, ensuring it remains within the VFD’s acceptable range (typically 380V ±15%).
• Electromagnetic Interference: Assess whether strong interference sources, such as high-power equipment or unshielded cables, are present on-site.

6. Observe Load Behavior

• Under safe conditions, disconnect the motor power and observe whether the load moves due to external forces or mechanical looseness.

---

Fault Resolution Measures

Based on the identified causes, the following are specific solutions:

1. Repair Brake System

• Circuit Repair: Replace damaged wiring or components to ensure accurate brake command transmission.
• Brake Adjustment: Repair or replace the brake to ensure sufficient braking force and timely response.

2. Optimize Parameter Settings

• Enable Detection Function: Set [BRH b5] to “YES” to activate load movement detection.
• Adjust Torque Threshold: Configure [TTR] based on load characteristics to ensure appropriate detection sensitivity.
• Match Control Type: Set [CTT] to [FVC] or [FSY] to align with the motor type.
• Extend Holding Time: Adjust [MD FT] to an appropriate value (e.g., 5 minutes) to prevent false alarms after power restoration.

3. Strengthen Mechanical System

• Tighten Components: Secure or replace loose transmission components.
• Secure Load: Add fixing mechanisms to ensure load stability.

4. Improve Electrical Environment

• Stabilize Power Supply: Install a voltage regulator or UPS to maintain stable voltage.
• Reduce Interference: Shield control circuits and optimize equipment layout to minimize electromagnetic interference.

5. Clear Fault Code

• Reset Operation: After resolving the issue, use the [ATR] (automatic fault reset) or [RSF] (reset fault) parameter to clear the error code. If necessary, reset [MTBF] (load holding delay) by powering off and restarting the device.

---

Preventive Measures

To reduce the likelihood of “Load Movement Error,” users can implement the following preventive measures:

1. Regular Maintenance

• Brake System: Inspect the brake and its circuit monthly, replacing worn components promptly.
• Mechanical System: Regularly tighten transmission components to prevent looseness.

2. Standardized Parameter Management

• Parameter Backup: Save parameter configurations after commissioning for quick restoration after faults.
• Periodic Review: Check critical parameters (e.g., [BRH b5], [CTT]) quarterly to ensure correctness.

3. Personnel Training

• Operational Standards: Train operators on proper VFD usage to avoid errors.
• Emergency Handling: Teach basic fault diagnosis skills to improve response capabilities.

4. Optimize Operating Environment

• Power Protection: Ensure a stable power supply to avoid fluctuations.
• Interference Mitigation: Optimize wiring to reduce electromagnetic interference.

---

Conclusion

The “Load Movement Error” is a common fault in Schneider ATV340 VFDs, potentially caused by brake system failures, incorrect parameter settings, mechanical looseness, electrical issues, or external forces. Through systematic diagnosis—reviewing fault information, inspecting brake and mechanical systems, and adjusting parameters—users can effectively identify and resolve the issue. Additionally, preventive measures such as regular maintenance, standardized operations, and environmental optimization can significantly reduce fault occurrences, ensuring long-term stable equipment operation.

In industrial automation, promptly and accurately addressing VFD faults is critical to maintaining production efficiency and safety. This document aims to provide practical guidance to help users better understand and manage the ATV340’s “Load Movement Error,” enhancing their confidence and capability in equipment management.

---

I. Overview

In modern industrial automation control systems, inverters play an extremely crucial role. The ATV630 series inverters launched by Schneider Electric are widely used in fields such as fans, pumps, and compressors, offering energy efficiency, flexible control, and extensive communication capabilities. However, during actual use, users may occasionally encounter a fault message on the screen indicating “Safety Function Error,” often accompanied by a status display of “STO,” indicating that the inverter is in a safe shutdown state.

This article provides a detailed analysis of the meaning of this error, its possible causes, wiring considerations, and practical methods for troubleshooting and resolving the fault.

II. Fault Meaning Analysis

On the ATV630 inverter, the “Safety Function Error,” or SAFF (Safety Function Fault), is a type of fault related to the STO (Safe Torque Off) safe shutdown function.

2.1 Overview of STO Function

STO (Safe Torque Off) is a safety function compliant with the IEC 61800-5-2 standard. Its primary role is to quickly disconnect the motor torque by shutting off the power output to the motor without cutting off the main power supply of the inverter.

2.2 Meaning of SAFF Fault

According to Schneider’s official manual, the specific definitions and possible causes of SAFF (safety function error) are as follows:

Possible Causes:

• Inconsistent states (high/low) of the STOA and STOB inputs for more than 1 second;
• Debounce time timeout;
• Internal hardware failure (modules related to safety functions).

Solutions:

• Check the wiring of the STOA and STOB digital inputs;
• Verify that jumpers are reliably connected;
• Contact Schneider’s official technical support if necessary;
• Clear the fault by performing a power reset.

III. Wiring Principles and Common Error Analysis

The STO function of the ATV630 typically uses terminals “STOA” and “STOB” to receive 24V inputs. Both ports must be at a high level simultaneously for the inverter to operate.

3.1 Standard Wiring Method

STOA ←→ 24VDC

STOB ←→ 24VDC

If the safety function is not used, “STOA” and “STOB” can be connected to “24V” respectively using short jumpers on the terminal block.

For example, in the picture you uploaded, the yellow jumpers connect “STOA→24V” and “STOB→24V,” which is theoretically correct.

3.2 Common Wiring Errors

• Connecting only one STO port (e.g., only STOA):
  This leads to inconsistent states between the two, triggering the SAFF.
• Loose or poor contact wiring:
  Loose plugs, oxidation, or insufficient tightening can cause intermittent faults.
• Incorrect jumper placement or use of non-industrial-grade wires:
  This can result in high-frequency interference or open circuits in the wiring.

IV. Detailed Troubleshooting and Resolution Steps

Step 1: Check STO Wiring

• Turn off the power and open the terminal cover;
• Verify that both STOA and STOB are connected to 24V and ensure reliable connections;
• If the safety circuit is not used, short-circuit “STOA” and “STOB” using industrial-grade copper wires;
• Use a multimeter to measure the voltage of STOA and STOB relative to ground to confirm it is around 24V.

Step 2: Observe Parameter Status

From the current control panel screenshot:

• ETA state word = 0x0050
• ETI state word = 0x0003
• Cmd word = 0x0006
• Drive state = STO

This indicates that the inverter has detected that the STO signal is not satisfied, preventing it from running.

Step 3: Fault Clearance Method

According to the manual, SAFF-type faults must be cleared by power cycling:

• Disconnect all main and control power supplies;
• Wait 15 minutes for the DC bus capacitors to fully discharge;
• Ensure correct wiring before reapplying power;
• Press the “STOP/RESET” button or use the rP parameter to restart the product;
• The fault should be cleared. If it persists, consider hardware issues or the use of an external safety circuit mode.

V. Extended Analysis: Is Enhanced Safety Function Enabled?

In certain applications, enhanced safety function modules (such as safety relays, Pilz, Sick, etc.) may be enabled, requiring STOA and STOB to be closed through these certified devices. If you have enabled “safety module enable (e.g., parameters such as SDI, IFSB, etc.),” the following situations may occur:

• The wiring appears correct, but the inverter’s internal logic judges it as illegal;
• The safety circuit must be closed within a specific time window; otherwise, a timeout will occur.

Check Parameters
Access the menu via the graphic terminal:
[Full Menu] → [Input/Output Configuration] → [Safety Function Allocation]
Check whether parameters such as “STO Input Allocation” and “Fault Reset Allocation” are controlled by external signals.

VI. Practical Suggestions and Summary

1. When using default jumpers, ensure:

• Use a dual-core yellow wire to jump STOA and STOB to 24V;
• Ensure good contact, no oxidation, and no broken strands;
• Avoid cross-wiring with other I/Os.

2. When enabling safety functions, it is recommended to configure:

• Use external safety modules compliant with PLe/SIL3 levels;
• Use example wiring diagrams provided by Schneider to avoid logical confusion;
• Configure digital inputs to monitor the status of the safety circuit (e.g., DI5/DI6 to monitor STO feedback).

3. Fault clearance sequence:

• Eliminate the root cause of the fault;
• Ensure correct wiring;
• Perform a RESET or power cycle;
• Check whether “Fault Reset” and “STO Configuration” are activated in the menu.

VII. Conclusion

Although the “Safety Function Error” is a common protection mechanism in the ATV630 series, its underlying principle is to protect equipment and personnel safety. Understanding its working mechanism and control logic is crucial. Proper handling of STO ports and parameter configuration is the basic prerequisite for ensuring the safe operation of the equipment.

Through the systematic explanation in this article, readers should now be able to independently address such issues, quickly locate and accurately resolve them, and avoid situations where equipment cannot operate due to “STO false alarms.”

---

---

1. Project Overview

This project aims to build a control network without using a PLC by directly connecting 9 Schneider Altivar-310 series variable frequency drives (VFDs) to a human-machine interface (HMI) through the Modbus TCP protocol. The HMI serves as the sole Modbus master, and all VFDs function as slave devices, enabling direct command transmission, status monitoring, and parameter interaction.

This architecture is especially suitable for small to medium automation systems, reducing hardware costs, simplifying the control structure, and improving debugging efficiency.

---

2. Hardware Checklist

Item	Function	Notes
Altivar 310 + VW3A3616 module × 9	Ethernet interface for each VFD	Install securely into the communication option slot
Industrial Ethernet switch (≥10 ports, 100 Mbps is fine)	Star topology backbone	DIN-rail mount, industrial-grade recommended
Shielded CAT5E/6 Ethernet cables	Noise-resistant communication	Keep under 100 meters; ground shield at one end
HMI panel supporting Modbus TCP	Acts as the master device	Weintek, Schneider Magelis, and similar brands recommended
24V DC power supply (if required by HMI)	Auxiliary power source	All devices should share the same PE grounding system

---

3. Recommended IP and Modbus Address Allocation

VFD No.	Static IP	Subnet Mask	Modbus Slave ID
1	192.168.0.11	255.255.255.0	1
2	192.168.0.12	255.255.255.0	2
…	…	…	…
9	192.168.0.19	255.255.255.0	9

Tip: Assign the HMI an address like 192.168.0.10. If used in an isolated system, the gateway can be set to 0.0.0.0.

---

4. Configuring IP Address for Each VFD Using SoMove

1. Connect the PC to the VFD via Ethernet cable and set the PC’s IP address to the same subnet (e.g., 192.168.0.100).
2. Launch the SoMove software, select Modbus TCP as the communication type, and enter the target VFD’s IP address (default or temporary), with Modbus slave address set to 1.
3. In the Communication → Ethernet menu:
   • Set IP Mode to Manual
   • Enter a unique static IP for each VFD (e.g., 192.168.0.15)
   • Set subnet mask to 255.255.255.0
   • Set gateway to 0.0.0.0 or as required by your network
   • Set protocol to Modbus TCP (value = 0)
   • Set Modbus slave address from 1 to 9
4. Save the parameters and reboot the VFD to apply the new IP.
5. Repeat this process for all 9 drives, assigning unique IPs and Modbus IDs.

---

5. HMI Modbus Register Mapping Example

Function	Register Address (Offset)	Data Type	Scaling
Command word (Run/Stop, Direction)	0	16-bit	Bit-level
Frequency setpoint (Hz)	1	16-bit	0.1 Hz per bit
Output frequency feedback	102	16-bit	0.1 Hz per bit
Drive status word	128	16-bit	Bit-level
Fault code	129	16-bit	Integer

Note: The ATV310’s Modbus register map starts at 40001. Some HMI brands use “offset 0”, so register 1 corresponds to 40001.

---

6. Network Topology and Installation Practices

1. Star Topology: Connect all 9 VFDs and the HMI to a central switch.
2. EMC Wiring Practices:
   • Separate power and Ethernet cable routing to minimize interference
   • Bond all VFDs and the switch ground terminals to the control cabinet’s PE bar
3. Labeling and Documentation:
   • Clearly label each Ethernet cable with corresponding VFD number and IP
   • Place a printed network topology diagram inside the control cabinet

---

7. Commissioning Procedure

1. Ping Test: Use a PC to ping each VFD’s IP address to verify communication.
2. HMI Communication Test:
   • Create a template screen for one VFD
   • Copy it for other VFDs, changing only the IP and Modbus ID
   • Test frequency control, start/stop, and feedback display for each unit
3. Stress Test: Run rapid start/stop cycles and observe response consistency and screen refresh speed (<200 ms is ideal).
4. Project Backup: Save each VFD’s .stm file from SoMove and the full HMI project into a version-controlled system.

---

8. Performance & Limitations

Aspect	Details
Max refresh speed	Reading 10 registers per drive takes ~20–40 ms; 9 drives ≈ 200–400 ms total
Real-time behavior	Suitable for monitoring and basic control; not ideal for high-speed interlocks (<20 ms)
Redundancy	A single switch failure disconnects all; consider dual-ring switches for critical uptime
Security	Use VLANs or restrict switch ports to specific MACs to prevent unauthorized connections

---

9. Maintenance and Optimization Tips

• Always backup SoMove configuration files after parameter changes
• Stick Modbus slave ID labels onto each VFD’s front panel
• Lock HMI screens with password protection to prevent accidental changes
• Annually inspect Ethernet switch ports; replace the unit if CRC errors or dust buildup is found

---

10. Conclusion

By installing VW3A3616 modules and configuring individual IP addresses and Modbus IDs for each ATV310, a clean star-topology network can be built for direct HMI communication. This setup simplifies wiring, eliminates the need for a PLC, and significantly reduces costs. It is particularly suitable for small to medium-sized automation projects that require easy maintenance and flexible deployment.

---

（1） Hardware Preparation & Network Setup

• Ethernet Module Installation: The ATV310 VFD does not include a built-in Ethernet port. To enable Modbus TCP over Ethernet, install an optional communication module such as the VW3A3616, which provides an RJ45 interface. Ensure the module is properly mounted and securely inserted into the option slot on the drive.
• Connecting the Network: Connect the VFD’s Ethernet port directly to your PC using a standard Ethernet cable, or connect both to the same switch. Configure your PC’s Ethernet interface to be in the same subnet—for example, assign it an IP like 192.168.0.10 with subnet mask 255.255.255.0. Disable firewalls to avoid communication issues.
• Initial IP Setup via HMI Panel: If this is the first time using the Ethernet module, its IP address may default to 0.0.0.0, awaiting DHCP. Since you are using static IPs, enter the ATV310’s local HMI panel, navigate to the “Communication (COM-)” → “Ethernet (EtH-)” menu, set IP Mode to “Manual”, and configure a temporary IP (e.g., 192.168.0.15) with the appropriate subnet mask. If there’s no router, set the gateway to 0.0.0.0. After setting, power cycle the VFD to apply the changes.

---

（2） Connecting to the ATV310 in SoMove

1. Launch SoMove: Ensure the SoMove software is installed along with the DTM driver package compatible with the ATV310 (usually compatible with ATV31/ATV312 profiles). Open SoMove and start a new project or open an existing one.
2. Set Up Communication:
   • Click “Edit Connection/Scan” and choose Modbus TCP as the connection type.
   • Click the advanced settings (gear icon), then under the “Scan” tab, choose Single Device, enter the temporary IP (e.g., 192.168.0.15) and slave address (default is 1).
   • Apply and save the configuration.
3. Scan and Connect: From the main screen, click “Scan”. If the IP and settings are correct, the VFD will be detected. Double-click it to establish the connection and load parameters.

---

（2） Setting the Static IP Address

Once connected, go to the Communication menu in the device parameter tree, then open the Ethernet (EtH-) submenu. Configure the following:

• IP Mode (IpM): Set to Manual (0) to disable DHCP.
• IP Address (IPC1–IPC4): Set the 4 bytes individually. For example, to set 192.168.0.15, enter IPC1=192, IPC2=168, IPC3=0, IPC4=15.
• Subnet Mask (IPM1–IPM4): Use a typical mask such as 255.255.255.0 (i.e., IPM1=255, IPM2=255, IPM3=255, IPM4=0).
• Gateway (IPG1–IPG4): If you’re not using routing, set it to 0.0.0.0.
• Ethernet Protocol (EthM): Ensure it is set to 0 for Modbus TCP (not Ethernet/IP).

Parameter Summary:

Parameter Code	Function	Recommended Setting
IpM (IP Mode)	IP acquisition method	0 = Manual (disable DHCP)
IPC1~IPC4	IP address	e.g., 192.168.0.15
IPM1~IPM4	Subnet mask	e.g., 255.255.255.0
IPG1~IPG4	Gateway address	e.g., 192.168.0.1 or 0.0.0.0
EthM (Protocol)	Modbus TCP or Ethernet/IP	0 = Modbus TCP

Once settings are applied, write them to the drive and power cycle the VFD to activate the new static IP address.

---

（4） Verifying the Configuration

1. Ping Test: From your PC, use the ping command to check if the VFD responds to the new IP address (e.g., ping 192.168.0.15). A successful response confirms network connectivity.
2. Reconnect in SoMove: Update the connection settings in SoMove with the new static IP and reconnect. You should be able to scan, access parameters, and monitor status.
3. Check Ethernet Module LEDs: A solid green light typically indicates normal status. Blinking or red lights may indicate wiring errors, IP conflicts, or module faults.
4. Modbus Communication Test: If integrating with an HMI or master software, send basic Modbus commands (e.g., reading frequency or writing speed setpoints) to ensure the VFD communicates correctly over Modbus TCP.

---

Conclusion

By following the above procedure, each ATV310 VFD can be configured with a unique static IP and operate reliably over an Ethernet network using Modbus TCP. This setup is especially effective in systems where communication is directly between an HMI and multiple drives, eliminating the need for a PLC. Proper IP planning, secure connections, and careful testing will ensure a stable and responsive network.

1. Meaning and Essence of the ILF Fault Code

1.1 Definition of the ILF Fault Code

The ILF fault code in Schneider ATV61 inverters stands for “Internal Link Fault.” Specifically, the ATV61 inverter comprises two main components: the control card and the power card. The control card is responsible for logical operations and parameter control, while the power card drives the motor. These two components communicate via an internal communication link, typically a high-speed communication bus. When this communication link encounters issues, the inverter detects the anomaly and triggers the ILF fault code, halting operation to protect the equipment.

1.2 Essence of the ILF Fault

From a technical perspective, the essence of the ILF fault is an interruption or data transmission error in the communication between the inverter’s control card and power card. This communication interruption can be caused by several factors:

• Hardware Issues: Loose, damaged, or poor physical connections (such as communication cables or connectors) between the control card and the power card.
• Component Failure: Hardware damage to the control card or power card, such as burnt chips or aging circuit boards.
• Electromagnetic Interference (EMI): External EMI or poor grounding causing unstable communication signals.
• Firmware Issues: Incompatible or corrupted firmware versions between the control card and power card, leading to the inability to execute communication protocols properly.

The occurrence of an ILF fault typically results in the inverter stopping operation and alerts the user via the display or status indicators (such as RUN, CAN, and ERR lights).

2. Possible Causes of the ILF Fault

2.1 Hardware Connection Issues

The control card and power card within the ATV61 inverter are connected via dedicated communication cables or connectors. If these connections become loose, poorly contacted, or damaged during operation, communication will be interrupted.

2.2 Control Card or Power Card Failure

The control card and power card are core components of the inverter. If either card’s hardware fails (e.g., chip damage or circuit board burnout), the communication link will not function properly.

2.3 Electromagnetic Interference

Inverters are often installed in industrial environments with high-power equipment, motors, or other sources of electromagnetic interference. If the inverter’s grounding is inadequate or shielding measures are insufficient, communication signals may be disrupted.

2.4 Incompatible or Damaged Firmware

If firmware upgrades fail or the firmware versions of the control card and power card are mismatched, the communication protocol may not execute correctly, triggering the ILF fault.

2.4 Other Potential Factors

• Environmental Factors: High temperatures, humidity, or dust may cause internal components to age or short-circuit.
• Misoperation: Users may accidentally set incorrect parameters or damage hardware during debugging or maintenance.
• Power Issues: Abnormal input power may interfere with the normal operation of the inverter.

3. Handling Methods for the ILF Fault

3.1 Preliminary Checks and Safety Preparations

• Power Off: Turn off the inverter’s power and wait at least 5 minutes to ensure the internal capacitors discharge completely.
• Wear Protective Gear: Wear insulating gloves and shoes, and use appropriate tools.
• Record Fault Information: Record the inverter’s model, firmware version, and fault details.

3.2 Check Hardware Connections

• Check Internal Communication Cables: Ensure cables are not loose, broken, or have poor contact. Reinsert or replace them if necessary.
• Check Connectors: Clean connectors to ensure good contact.

3.3 Investigate Control Card and Power Card Failures

• Replacement Testing: Replace the control card or power card one by one to test if the fault disappears.
• Check Hardware Status: Inspect for obvious physical damage.

3.4 Reduce Electromagnetic Interference

• Check Grounding: Ensure grounding resistance is less than 4 ohms.
• Shielding Measures: Add shielding covers or adjust equipment layout.
• Check Power Quality: Measure input power voltage and frequency, and install power filters if necessary.

3.5 Check Firmware Versions

• View Firmware Information: Confirm that the firmware versions of the control card and power card match.
• Firmware Recovery or Upgrade: Download the latest firmware from Schneider’s official website and upgrade.

3.6 Reset the Inverter

• Power Cycle: Reconnect power and observe if the fault disappears.
• Restore Factory Settings: Reset to factory settings via the menu [1.8 Fault Management] (FLt-) to restore factory settings.

3.7 Contact Technical Support

• Contact Us for Handling: If the above steps fail, seek professional help.
• Provide Information: Prepare the inverter model, firmware version, and fault details.

4. Suggestions for Preventing ILF Faults

• Regular Maintenance: Inspect internal connections and cleanliness every six months.
• Optimize Operating Environment: Ensure proper ventilation and temperature control.
• Standardized Operation: Follow the user manual strictly.
• Monitor Power Quality: Regularly check the stability of the input power supply.

5. Summary

The ILF fault reflects abnormalities in the internal communication link of the ATV61 inverter. Through systematic troubleshooting methods and preventive measures, users can effectively resolve issues and ensure the stable operation of the equipment.

---

Meaning of the INF6 Fault Code

The INF6 fault in Schneider Electric’s ATV71 variable frequency drive (VFD) indicates an internal option card fault, specifically that the drive fails to detect or recognize an installed option card. This card could be a communication module, encoder feedback interface, or an I/O extension board, all of which are connected via internal slots to the main control board.

In crane applications, option cards are frequently used for advanced functions such as closed-loop vector control via encoder feedback or communication with PLCs or remote systems through fieldbus networks like Profibus, CANopen, or Modbus.

---

Typical Scenarios Leading to INF6 in Crane Environments

1. Card Loose or Poor Contact Due to Vibration
   Cranes often cause mechanical vibration and shock, especially during lifting or brake engagement. These vibrations can loosen option cards that are not well-secured, leading to intermittent or complete disconnection from the control board.
2. Incompatibility or Conflict Between Cards
   Installing incompatible option cards or using two mutually exclusive modules can lead to detection failures. For instance, some ATV71 models do not support simultaneous installation of multiple communication cards.
3. EMI (Electromagnetic Interference)
   High-voltage motors, contactors, and solenoids in cranes generate strong electrical noise. If signal lines or the power supply to the card are interfered with, the card may fail during boot-up, leading to INF6.
4. Hot-Swapping or Improper Handling
   Inserting or removing cards while the drive is powered can instantly damage internal circuits or corrupt detection logic.
5. Card Failure or Aging
   Cards may fail due to temperature stress, component aging, or EEPROM corruption, particularly in harsh crane environments.

---

On-site Troubleshooting Process and Required Instruments

1. Safety Shutdown and Visual Inspection

• Disconnect all power and wait for DC bus discharge.
• Remove the front cover of the VFD and inspect the option card seating.
• Re-insert and firmly fix the card to ensure solid contact.

2. Socket and PCB Inspection

• Examine socket pins for oxidation, damage, or bent pins.
• Use a flashlight and multimeter (in continuity mode) to check connection integrity between slot pins and main board.
• Clean contacts with alcohol if dirt or corrosion is found.

3. Substitution Testing

• Insert a known-good card to see if the error clears.
• Try the faulty card in a different VFD. If the error moves with the card, the card is faulty. If not, suspect the VFD mainboard.

4. Firmware and Parameter Checking

• Connect a PC via Schneider’s SoMove software and read diagnostic registers.
• Check if the card appears in the identification menu. If not, it’s either faulty or incompatible.
• Confirm compatibility of the card model with current firmware version.

5. Instrumental Diagnosis

• Multimeter: Measure slot power pins (usually +5V or +24V).
• Oscilloscope: Check clock/data lines of the card communication interface (e.g., SPI, I²C).
• Thermal Camera: Detect abnormal heat signatures on card or mainboard.
• Bus Analyzer: For communication cards, monitor if signals are transmitted at all.

---

Maintenance and Repair Strategy

Basic Solutions

• Reseat the card and retest.
• Replace card if visibly damaged or if substitution confirms card failure.
• Remove additional cards if there is a slot conflict.

Power Supply Repair

• If slot voltage is missing or unstable, investigate the power regulator or filtering section of the mainboard.

Cold Solder Joint Repair

• Check socket solder points under magnification. Repair any cracked or cold solder joints using a soldering iron.

Firmware Updates

• If firmware mismatch is suspected, update the drive firmware using official Schneider tools.

Observe Handling Rules

• Always power down before inserting/removing cards.
• Avoid touching card contacts with bare hands.

---

Advanced PCB-Level Diagnostics (for Experienced Engineers)

If all above steps fail:

1. Study Schematics
   Locate option slot pin functions and their connections to ICs or CPU.
2. Signal Tracing
   Use an oscilloscope or logic analyzer to trace data lines between the card and CPU. Look for absence or corruption of signals.
3. Component Testing
   • Check if line driver/receiver ICs (e.g., RS-485 transceivers) are working.
   • Verify presence of proper clock signals and EEPROM integrity.
4. Chip Replacement
   • If suspect components (e.g., voltage regulators, buffer ICs) are identified, carefully desolder and replace them.
   • Use thermal camera post-repair to confirm heat profile normalization.

---

Summary

For a field engineer maintaining crane control systems, an INF6 error is not just a code—it’s a call for systematic diagnosis. Whether caused by vibration, poor contact, firmware mismatch, or a damaged card, INF6 can typically be resolved with structured inspection and substitution.

When the root cause lies deeper—within power supplies, communication buses, or chip-level failures—a disciplined approach using schematics, meters, and scopes becomes essential. Through careful inspection, methodical replacement, and sometimes PCB-level repair, an engineer can confidently restore the VFD’s full functionality.

Let this guide serve as your reference for future INF6 cases on Schneider ATV71 drives, ensuring minimal downtime and safe crane operation.

---

---

I. Introduction

In modern industrial automation, the Human Machine Interface (HMI) plays a critical role in boosting production efficiency and ensuring operational safety. Pro-face, a Japanese brand well-known in the HMI field, has adopted a modular design in its SP series touchscreens: users can freely choose different display sizes and pair them with the appropriate “box modules” to handle complex control tasks. Thanks to this design, the Pro-face SP series is widely used across industries such as machinery manufacturing, electronics assembly, pharmaceuticals, and food processing.

Despite its popularity, many users have questions when disassembling or maintaining an SP series touchscreen. Specifically, they may wonder about the module located on the back that looks like a “power box” or “processor unit.” What function does it serve? If you remove this module, can the display still operate as long as it is powered? This article will take an in-depth look at the Pro-face SP-5B10 (PFXSP5B10) box module—its features and importance, how it interacts with the display module, and whether or not the touchscreen can still function normally once the module is removed.

---

II. Overview of the Pro-face SP-5B10 Module

1. Module Positioning: The Core Processing Unit of the HMI

The Pro-face SP-5B10 box module (also known as the “enhanced box module” or “Power Box”) is the “brain” of the SP5000 series touchscreen system. It houses the processor, memory, and various industrial communication interfaces. Unlike a traditional, single-unit HMI device, Pro-face introduced a modular approach in the SP series by separating the display section and the processing section, referred to as the display module and the box module, respectively. As the box module, SP-5B10 is in charge of running control logic, storing project data, connecting devices via different networks, and overseeing the overall operation of the system.

2. The “Brain” for Running Business Logic and Display Screens

In practical applications, an HMI often needs to run custom programs for production lines, equipment, or processes—such as displaying workflows, monitoring real-time data, and sending or receiving control commands. These configured screens and logic programs are developed via software like GP-Pro EX and are downloaded to the box module. The SP-5B10 provides ample processing power and memory to execute these screen logics, data collection tasks, and alarm management. It then transmits the resulting display data to the display module. Essentially, without the box module’s processing and control, the HMI’s “intelligence” does not exist, and the touchscreen would be reduced to a blank display panel.

3. Data and System Software Storage

The SP-5B10 box module integrates storage features, including an SD card slot, internal flash memory, and backup battery. In more detail:

• System Storage: Contains the HMI’s system firmware, operating system, and basic drivers needed for startup.
• Project Data Storage: Stores project files, alarm information, recipe data, etc., that are downloaded from development software such as GP-Pro EX. This approach allows easy maintenance; for instance, if the display module needs replacing, simply removing and reattaching the box module or swapping the storage card can restore the entire application.
• Alarm and Historical Records: Many industrial environments require the recording of alarm data and operational logs—sometimes for weeks or months. The SP-5B10’s internal flash memory or SD card meets these demands.

4. The Central Hub for Multiple Industrial Communication Interfaces

In industrial settings, an HMI commonly exchanges data with PLCs, inverters, sensors, or upper-level management systems, making diverse interfaces and protocols critical. The SP-5B10 often includes:

• Ethernet Ports: Typically at least one or two RJ-45 ports supporting 10/100/1000 Mbps to connect PLCs, SCADA, or MES systems.
• Serial Interfaces (COM Ports): RS-232C, RS-422/485, etc., for older PLCs and instruments still widely used.
• USB Host/Device Ports: For connecting USB peripherals such as flash drives or barcode scanners, as well as for direct communication or program downloads from a PC.
• Expansion Bus: Some box modules allow additional interface cards (e.g., fieldbus expansions, field I/O boards) to suit a variety of automation scenarios.

As the conduit for all external signals and data, the SP-5B10 processes information before passing it on to the display module, allowing seamless “field–HMI–network” connectivity.

---

III. How the SP-5B10 Works with the Display Module

1. Physical Connection: A Rear Plug-in Connector

In the Pro-face SP5000 series, the box module and display module link up via a specialized connector on the display’s rear side. The box module securely latches onto the display module through a rail or clip mechanism:

• Power Supply: The display module connects to external power (e.g., 24 V DC) and converts it internally to power the box module, which does not require its own power input.
• Signal Transmission: The connector transmits video signals while also carrying touch input signals and other data between the processor and display.

This modular concept makes it easy for users to replace or upgrade components. For example, if you want to switch to a larger display but keep the same box module, simply remove the original display and connect the SP-5B10 to a new, larger SP series display. Likewise, if you need higher processing performance, you can upgrade only the box module without having to swap out the entire display screen.

2. Logical Coordination: Clear Division of Labor, Integrated Operation

The SP-5B10 handles core computing, communications, and data storage, while the display module is responsible for UI presentation and touch sensing. Their cooperation can be summarized as:

• Screen Data Transmission: The SP-5B10 runs the screen logic and sends the display content to the display module, which then renders and displays it.
• Touch Feedback: When an operator touches a button or drags an object on the screen, the display module detects the action and relays it back to the box module for processing, which either responds or carries out related control commands.
• System Health Management: If the box module detects high temperature or an internal fault, it can alert the display module to show warnings or shut off the backlight, ensuring safe operation of the entire system.

---

IV. What Happens if You Remove the SP-5B10?

Many wonder whether the front display panel can still function if the box module is taken out. The short answer is no. The SP-5B10 is not a simple add-on accessory; it is the “brain” and “heart” of the entire HMI system. Once it is removed, the display module loses its processor, memory, and communication interfaces, which means it becomes non-functional. Specifically:

1. No Display
   Without the display data provided by the SP-5B10, the screen may only have power for the backlight (if at all) but will show no graphics or text. All HMI screens are generated by the box module, so with it removed, there is no output signal for the display panel.
2. No Touch Operation
   Since no box module is present to read and process touch coordinates, any touch input is rendered meaningless. Typically, the screen’s coordinate signals must be sent to and interpreted by higher-level software or the OS, which runs on the SP-5B10.
3. Loss of Data Collection and Communication
   The box module provides interfaces like serial ports, Ethernet, and USB. Removing it also removes these interfaces, and thus the touchscreen can no longer communicate with PLCs, sensors, or PCs. Effectively, all monitoring and control functions cease.
4. Loss of System and Project Data
   The SP-5B10 stores screen projects, recipes, alarm history, and more on an SD card or in internal memory. Removing the module effectively takes away all critical data needed for system operation. The display module itself usually does not retain these files and cannot independently load the application.

Hence, removing the SP-5B10 renders the Pro-face touchscreen incapable of displaying or interacting with any functionality. The system will only resume normal operation once the box module (or a compatible alternative) is reattached and powered up.

---

V. Conclusion and Recommendations

In summary, the Pro-face SP-5B10 box module is an irreplaceable core component of the SP series touchscreen. It not only handles screen display and touch input processing, but also provides the storage space, communication interfaces, and expansion capabilities vital for complete HMI functionality. For engineers and maintenance personnel who rely on Pro-face HMIs for field device monitoring, data collection, and process visualization, ensuring that the box module and display module remain properly connected and functioning is crucial.

If you need a functioning display, you cannot rely solely on the screen hardware. During maintenance, if you must remove the box module, always do so with the power off and take precautions to protect the storage card and the module from static or physical damage. Bear in mind that once the SP-5B10 is removed, the touchscreen loses its central processing capability and will not operate; only by reinstalling the compatible box module and powering the system can normal functions be restored.

In essence, the SP-5B10 module is like the processor and storage system in a smartphone—without it, even the best screen is just inert “glass.” Removing it inevitably leads to loss of the original interface, disabling any touch inputs or data communications. Therefore, to ensure stable, continuous operation of Pro-face HMIs, the SP-5B10 and display module must remain tightly integrated so that the system can take full advantage of the module’s high-speed processing and multi-interface communication features, enabling better equipment monitoring and process management on the industrial floor.

---

---

I. Background and Importance

Within the realm of industrial automation, frequency inverters have become indispensable for motor control. Schneider Electric’s ATV series inverters enjoy a strong reputation for reliability and versatility, making them popular in many factories and engineering projects. The ATV303, in particular, is a cost-effective model frequently used with fans, pumps, and conveyor systems. For maintenance personnel, a solid understanding of the inverter’s fault and status codes is crucial for improving production efficiency, reducing downtime, and preventing unnecessary equipment damage.

In actual usage, one may occasionally see the code “06” appear on the display panel of the ATV303 inverter. Since most real faults are labeled with an “F” prefix (e.g., F013 for motor overload or F011 for an overheat warning), many technicians might feel confused upon seeing “06”: Is it a fault code or just a normal state indicator? Is urgent shutdown and troubleshooting needed? In fact, the “06” code on the ATV303 is not a fault, but rather an indication of the Freewheel Stop state. This article provides a detailed explanation of the meaning of the “06” code, why it might appear, and how to deal with it properly so that readers can swiftly diagnose and address the situation.

---

II. The Real Meaning of Code 06

According to the official Schneider documentation for the ATV303, any code beginning with an “F” denotes an actual fault alarm—examples include F002, F006, F013, and so on. These alarms necessitate analysis of potential hardware or configuration issues, followed by the relevant reset or maintenance actions. In contrast, code “06” is explicitly categorized as a product status indicator. Rather than a hardware failure or system anomaly, it indicates a specific operational condition.

The “06” code stands for Freewheel Stop. In practical terms, freewheel stop means that the inverter is no longer supplying torque to the motor, allowing the motor shaft to come to rest solely through its own inertia. It differs from controlled or braked stopping methods: no active deceleration curve is applied, nor does the inverter inject direct current (DC) into the motor for braking. The time it takes the motor to stop primarily depends on load inertia.

Since the “06” state is not a failure, operators need not fear equipment damage or software errors. However, understanding why an inverter enters freewheel stop remains crucial. If “06” is triggered unexpectedly, it may disrupt normal operations or break the production rhythm. Only by identifying and addressing whatever caused the inverter to enter freewheel stop can the system resume normal operation.

---

III. Common Triggering Causes

1. Activation of a Logic Input
   The inverter’s logic inputs (e.g., LI1, LI2) can each be assigned custom functions. One of those functions is often “Freewheel Stop.” If a digital input is configured this way and happens to be energized—for instance, an external emergency stop circuit or sensor being triggered—then the ATV303 will automatically switch to freewheel stop and display “06.”
2. Selected Control Method
   In two-wire control setups (i.e., one input for Run/Stop), the inverter waits for a valid Run signal after power-up. If that signal is absent or the wiring logic dictates a stop condition, the inverter might remain in freewheel stop. In some designs, the user must explicitly toggle the Run input once the inverter is powered up before it can exit “06.”
3. Local/Remote Switching
   When the inverter is in remote-control mode, pressing the local STOP button or encountering a communication loss may force the inverter into freewheel stop. In these scenarios, code “06” will remain until a valid remote Run command is received again or communication is restored.
4. PID or Other Functional Settings
   If the inverter is configured for closed-loop PID control and the feedback signal is lost—or the user deliberately set a “freewheel stop on signal loss” strategy—the inverter will carry out that plan by showing “06.” Once the signal is restored or a different stopping approach is chosen, the operator must send a new Run command to exit freewheel stop.

---

IV. Handling Approach and Detailed Operation

1. Check the Logic Input Configuration
   If you suspect a particular digital input is assigned to freewheel stop, inspect the assignment in the inverter’s configuration menu (COnF). Should you find that an input is set for FSt (Freewheel Stop) and it is in an active state (e.g., turned on), you can disable this input or remove its power signal to release the inverter from freewheel stop, returning it to a ready state.
2. Examine Emergency Stop or Safety Circuits
   In many systems, an emergency stop circuit signals the inverter via a digital input or relay contact for freewheel stop. If an emergency stop is pressed, “06” will appear until you physically reset that emergency circuit. Ensure that no unsafe conditions remain in the machinery before re-engaging the e-stop circuit and clearing the “06” state.
3. Resend Run Command in a Two-Wire Control Setup
   In a two-wire control scheme, you often need to remove and then reapply the Run signal after power-up. Without this, the inverter stays in freewheel stop mode. Once you provide the correct Run input, the inverter leaves “06” and begins outputting to the motor.
4. Use a Start Button in a Three-Wire Setup
   If the system is wired for three-wire control (separate Start and Stop buttons), the inverter expects a start pulse after the stop button is released. Simply pressing the start button again should cause the display to switch from “06” to normal operation.
5. Check Communication Settings
   In scenarios where the inverter is governed by serial communication from a PLC or computer, the absence of a valid run command or a temporary communication fault can lead to freewheel stop. Verify that the communication settings (baud rate, parity, data bits) match, and confirm the controller has issued the correct commands to restore normal drive operation.
6. Avoid Signal Loss
   For advanced setups where the inverter is configured to freewheel stop upon losing an analog input (e.g., 4–20 mA), make sure sensors and cables are secure. Restoring the signal or adjusting the signal-loss strategy can eliminate “06.” Then, simply sending a valid run command should re-energize the motor.

---

V. Distinctions from Real Faults and Prevention

Unlike a code starting with “F,” which denotes actual faults requiring reset or more in-depth troubleshooting, “06” merely reflects the inverter’s execution of a normal freewheel stopping command. The user does not need to perform hardware inspections or a dedicated fault reset. However, an unintended or extended freewheel stop could disrupt production. Hence, it is crucial to configure your control logic carefully and secure all wiring to avoid unplanned “06” occurrences. Where higher safety requirements exist, you may prefer an alternative form of stopping such as fast ramp stop or DC injection, based on the demands of your process.

---

VI. Conclusion

To summarize, code “06” on the Schneider ATV303 inverter is not a sign of component malfunction. Instead, it indicates that the inverter is currently in Freewheel Stop mode—no torque or braking is being applied to the motor, so the load is free to coast to a standstill under its own inertia. Restoring normal operation involves determining the specific reason for freewheel stop—whether it’s a digital input function, an emergency stop condition, a missing run command, or a lost feedback signal. Once you remove or correct that cause, the inverter will automatically revert to a ready state (–00) or re-engage in normal operation if a run command is still active.

For real-world projects, ensuring your ATV303 is configured correctly—and that all external wiring and control signals are stable—will go a long way toward preventing unwanted freewheel stops from interrupting production. By grasping the function and handling of the “06” status, maintenance personnel can promptly troubleshoot and restore equipment to service, minimizing downtime and optimizing operational safety.

By understanding the meaning and responses associated with “06,” operators and technicians can effectively manage a common inverter behavior without confusion. Adhering to official Schneider documentation and combining that guidance with the specific control requirements of your system will ensure that the freewheel stop state works for you, rather than against you, in all industrial automation scenarios.

---