VFD Fault Code Troubleshooting: Systematic Diagnosis of Overcurrent, Overvoltage, Ground Fault, and Communication Errors

Problem Description & Scope

Variable Frequency Drives (VFDs) are critical components in modern industrial operations across the US and UK manufacturing sectors, offering precise motor control, energy efficiency, and extended equipment lifespan. However, VFDs are also susceptible to various fault conditions that can lead to nuisance tripping and unexpected downtime. This guide provides a systematic, diagnosis-first framework for identifying and resolving the root causes behind common VFD fault codes: overcurrent, overvoltage, ground fault, and communication errors.

This document addresses symptoms observed in a wide range of VFD-driven equipment, including pumps, fans, conveyors, compressors, and machine tools. Faults are generally classified by severity:

• Critical: Immediate shutdown, requiring urgent resolution to prevent production loss or secondary equipment damage.
• Major: Intermittent tripping or degraded performance, impacting efficiency and potentially leading to critical failure if unaddressed.
• Minor: Warning conditions or occasional, non-critical faults that still warrant investigation to prevent escalation.

Safety Precautions

WARNING: All VFD diagnostic and resolution procedures involve exposure to hazardous voltages, stored energy, and potential arc flash hazards. Failure to follow proper safety protocols can result in severe injury or fatality.

• Lockout/Tagout (LOTO): ALWAYS de-energize the VFD and associated motor circuit following OSHA 29 CFR 1910.147 (Control of Hazardous Energy) or equivalent local regulations. Verify zero voltage using a properly rated and calibrated multimeter.
• Stored Energy: VFD DC bus capacitors can retain dangerous voltage for several minutes after power removal. ALWAYS wait the manufacturer-specified discharge time (typically 5-10 minutes) and verify DC bus voltage is below 50V DC before touching any components.
• Personal Protective Equipment (PPE): Wear appropriate PPE, including arc-rated clothing (e.g., 8 cal/cm² for typical VFD work), electrical gloves, safety glasses, and non-conductive footwear, as dictated by your facility’s arc flash study and NFPA 70E requirements.
• Grounding: Ensure all test equipment is properly grounded.
• Bypass: Never bypass safety interlocks or protective devices during troubleshooting.

Diagnostic Tools Required

Effective troubleshooting relies on the correct application of specialized tools. Ensure all instruments are calibrated according to ANSI/NIST standards.

Initial Assessment Checklist

Before initiating detailed diagnosis, a thorough initial assessment can often provide crucial insights into the fault’s context and probable causes.

Systematic Diagnosis Flowchart

This flowchart provides a decision-tree approach to diagnose common VFD fault codes. Follow the steps sequentially based on the observed fault.

1. VFD Trips on Fault. Record Fault Code.
2. Is the fault an Overcurrent (OCx)?
   1. Does the Overcurrent occur immediately upon start?
      • Check 1: Motor Connections & Phase Balance.
        • Disconnect motor leads from VFD.
        • Measure resistance phase-to-phase (U-V, V-W, W-U). Expected: Balanced (within 5%) and low resistance (e.g., 0.1-5 Ω depending on motor size).
        • Measure resistance phase-to-ground (U-GND, V-GND, W-GND) with Megohmmeter at 500V or 1000V. Expected: >1.0 MΩ.
        • IF: Imbalance or low resistance phase-to-phase → Probable Cause: Motor winding short or incorrect wiring. Resolution: Repair/replace motor, correct wiring.
        • IF: Low resistance phase-to-ground → Probable Cause: Motor ground fault or cable ground fault. Resolution: Isolate motor vs. cable; repair/replace.
      • Check 2: Mechanical Load.
        • Is the driven equipment mechanically jammed or overloaded? Attempt to spin by hand if safe.
        • IF: Motor locked rotor / excessive breakaway torque → Probable Cause: Mechanical binding. Resolution: Clear jam, reduce load, inspect driven equipment.
      • Check 3: VFD Parameters.
        • Verify motor FLA, voltage, and RPM parameters in VFD match nameplate.
        • Check VFD acceleration ramp time. Is it too short for the load inertia? (e.g., <5 seconds for high inertia loads).
        • IF: Mismatch or excessively short ramp → Probable Cause: Incorrect VFD setup. Resolution: Adjust parameters according to motor nameplate and application requirements.
   2. Does the Overcurrent occur during operation (running)?
      • Check 1: Motor Current.
        • Use clamp-on ammeter to measure motor current on each phase (U, V, W) while running. Expected: Current should be at or below motor nameplate FLA (Full Load Amps).
        • IF: Current exceeds FLA → Probable Cause: Excessive mechanical load or failing motor bearings. Resolution: Reduce load, inspect/repair driven equipment, check motor bearings (vibration analysis).
      • Check 2: Load Transients.
        • Observe if fault occurs during sudden load changes or process events.
        • IF: Fault correlates with load transients → Probable Cause: Insufficient VFD sizing for dynamic loads or aggressive control loops. Resolution: Re-evaluate VFD sizing, adjust VFD gain/response parameters.
      • Check 3: VFD Cooling.
        • Is the VFD enclosure properly ventilated? Are cooling fans operational and clean?
        • IF: VFD overheating → Probable Cause: Inadequate cooling, dirty heatsink. Resolution: Clean filters/fans, ensure proper airflow, check ambient temperature.
3. Is the fault an Overvoltage (OVx)?
   1. Check 1: Input Line Voltage.
      • Measure input voltage at VFD terminals (L1-L2, L2-L3, L3-L1) using DMM. Expected: Within +/-10% of nominal VFD input voltage (e.g., 480V +/- 48V).
      • IF: Input voltage consistently high → Probable Cause: Utility supply issue or incorrect transformer tap setting. Resolution: Contact utility, adjust transformer taps.
   2. Check 2: DC Bus Voltage.
      • Monitor DC bus voltage via VFD display or programming software. Expected: Typically 1.35 * Peak AC input (e.g., for 480V AC, DC bus ~650-680V DC).
      • Does the DC bus voltage spike during deceleration?
        • IF YES: → Probable Cause: Regenerative braking from high inertia load. Resolution: Increase deceleration ramp time, install/check braking resistor, install braking unit.
      • Check 3: Braking Resistor.
        • (LOTO FIRST) Measure resistance of external braking resistor. Expected: Matches specification (e.g., 25 Ohms +/- 5%).
        • IF: Open circuit or high resistance → Probable Cause: Failed braking resistor. Resolution: Replace braking resistor.
4. Is the fault a Ground Fault (GFx)?
   1. Check 1: Motor and Cable Insulation.
      • (LOTO FIRST) Disconnect motor leads and input power from VFD.
      • Using Megohmmeter, test insulation resistance of motor windings to ground (U-GND, V-GND, W-GND) at 500V or 1000V. Expected: >1.0 MΩ.
      • Test insulation resistance of motor cable from VFD output to motor terminal box (T1-GND, T2-GND, T3-GND). Expected: >1.0 MΩ.
      • IF: Low insulation resistance on motor → Probable Cause: Motor winding insulation breakdown, moisture ingress. Resolution: Dry motor, rewind, or replace.
      • IF: Low insulation resistance on cable → Probable Cause: Damaged cable insulation (chafing, crushing, water ingress). Resolution: Replace motor cable.
   2. Check 2: VFD Output Stage.
      • (Only after ruling out motor/cable) If fault persists and motor/cable test clear, a fault within the VFD’s IGBT output stage is probable.
      • Resolution: VFD service or replacement. This often requires specialized VFD technician.
   3. Is the fault a Communication Error (COMx)?
      1. Check 1: Physical Connection.
         • Verify network cable integrity (e.g., Ethernet, RS-485). Check for cuts, kinks, loose connectors.
         • (LOTO FIRST if connecting to VFD terminals) Check terminal block connections for tightness.
         • IF: Physical damage or loose connection → Probable Cause: Damaged cable or poor contact. Resolution: Repair/replace cable, re-terminate connections.
      2. Check 2: Network Parameters.
         • Access VFD communication parameters (e.g., via HMI or programming software).
         • Verify communication address (e.g., Modbus ID), baud rate, parity, stop bits match network master.
         • Check network termination resistors (if RS-485/Profibus). Expected: Correct 120 Ω resistors at each end of the bus.
         • IF: Parameter mismatch or incorrect termination → Probable Cause: Incorrect network configuration. Resolution: Adjust VFD parameters, install/check termination resistors.
      3. Check 3: Network Traffic / EMI.
         • Observe network LED indicators on VFD and master. Look for excessive error lights.
         • Use oscilloscope to inspect RS-485 or fieldbus signals for noise or distortion.
         • Ensure proper cable shielding and grounding.
         • IF: Excessive errors or signal noise → Probable Cause: EMI interference, grounding loop, or overloaded network. Resolution: Improve cable shielding/grounding, isolate noisy sources, optimize network topology.

   Fault-Cause Matrix

   This matrix correlates observed symptoms with probable causes, diagnostic tests, and expected outcomes to guide rapid troubleshooting.

   Symptom	Probable Causes (ranked by likelihood)	Diagnostic Test	Expected Result if Cause Confirmed
   Overcurrent (OCx) – Immediate trip on start	1. Motor winding short or ground fault 2. Motor locked rotor / excessive breakaway load 3. Incorrect VFD motor parameters (FLA, accel time)	Insulation resistance test (motor, cables) Manual rotation of motor shaft VFD parameter verification	<1.0 MΩ (motor/cable) Motor unable to rotate freely Parameter mismatch, short accel time (e.g., <1.0s)
   Overcurrent (OCx) – Trips during run	1. Excessive mechanical load / motor bearing failure 2. Rapid acceleration/deceleration with high inertia 3. VFD output short or IGBT failure	Clamp-on ammeter for motor current (trend) VFD fault log analysis (time of trip) Visual inspection of VFD output stage, power cycling	Current consistently > Motor FLA (e.g., 110%) Fault consistently occurs during accel/decel ramp Visible damage to IGBTs, immediate trip on power-up
   Overvoltage (OVx) – Trip	1. Regenerative braking from high inertia load 2. High input line voltage / transients 3. Failed or undersized braking resistor	Monitor VFD DC bus voltage via HMI/software DMM for input line voltage (L1-L2, L2-L3, L3-L1) Resistance test of braking resistor (LOTO)	DC bus voltage > VFD threshold (e.g., >780V DC for 480V input) Input voltage > 528V AC (for 480V nominal) Open circuit or high resistance (e.g., >30Ω for 25Ω resistor)
   Ground Fault (GFx) – Trip	1. Motor winding insulation breakdown 2. Damaged motor power cable insulation 3. Moisture/contamination in motor or cable junction box	Insulation resistance test (motor, then cable) with Megohmmeter Visual inspection of motor terminal box and cable run	Motor/cable insulation resistance <1.0 MΩ Visible chafing, cuts, water ingress Condensation or foreign material present
   Communication Error (COMx) – Trip / No control	1. Network cable damage / loose connection 2. Incorrect VFD communication parameters (address, baud rate) 3. EMI interference / incorrect network termination	Continuity test of network cable VFD parameter verification (HMI/software) Oscilloscope on communication line (RS-485), check termination resistors	Open circuit or intermittent connection VFD address/baud rate does not match master Noisy signal, incorrect termination resistance (not 120Ω at ends)

   Root Cause Analysis for Each Fault

   Overcurrent Faults (OCx)

   Overcurrent faults occur when the motor draws current exceeding the VFD’s programmed limit or the drive’s internal component ratings. If left unresolved, persistent overcurrent can lead to motor winding degradation, premature VFD IGBT failure, and significant process downtime.

   • Mechanical Overload: This is a common cause, particularly in applications with varying load demands. A sudden increase in process material, binding bearings in the driven equipment, or a misaligned shaft can force the motor to draw excessive current to maintain speed. This leads to overheating in both the motor and VFD.
   • Motor Electrical Issues:
   • Winding Shorts/Ground Faults: Degradation of motor winding insulation due to age, heat, vibration, or moisture ingress can cause phase-to-phase or phase-to-ground shorts. These create low impedance paths, leading to very high currents.
   • Bearing Failure: Severely degraded motor bearings increase friction, causing the motor to work harder and draw more current. This is often accompanied by increased noise and vibration.
   • VFD Parameter Mismatch: Incorrectly set VFD parameters, such as motor FLA, acceleration/deceleration times, or current limits, can cause nuisance trips. An acceleration time that is too short for a high-inertia load will demand excessive current to rapidly increase speed, triggering an overcurrent fault.
   • VFD Output Stage Fault: Internal failure of VFD components, particularly the Insulated Gate Bipolar Transistors (IGBTs), can result in an output short circuit, leading to immediate and often catastrophic overcurrent faults.

   Overvoltage Faults (OVx)

   Overvoltage faults typically occur when the DC bus voltage within the VFD exceeds its safe operating limit. Prolonged overvoltage stresses the VFD’s DC bus capacitors and IGBTs, reducing their lifespan and potentially causing catastrophic failure.

   • Regenerative Braking: In applications with high inertia loads (e.g., centrifuges, large fans that decelerate quickly), the motor acts as a generator during deceleration, feeding energy back into the VFD’s DC bus. If this energy is not dissipated (e.g., by a braking resistor), the DC bus voltage will rise rapidly, triggering an overvoltage trip.
   • High Input Line Voltage: Fluctuations or sustained high voltage from the utility grid, or an incorrectly tapped transformer, can cause the rectified DC bus voltage to exceed the VFD’s rating. Transient voltage spikes can also induce temporary overvoltage conditions.
   • Braking Resistor / Unit Failure: If an external braking resistor or braking unit is installed to dissipate regenerative energy, an open circuit in the resistor, a faulty switching circuit, or an undersized resistor can prevent proper energy dissipation, leading to overvoltage.

   Ground Faults (GFx)

   A ground fault occurs when an energized conductor (phase or DC bus) inadvertently comes into contact with an equipment grounding conductor or the earth. This poses a significant safety hazard and can cause severe equipment damage if not promptly detected and interrupted. The VFD’s ground fault protection monitors current leakage to ground and trips when a preset threshold is exceeded.

   • Motor Winding Insulation Breakdown: This is a primary cause of ground faults. Factors such as extreme heat, moisture, abrasive dust, chemical exposure, or vibration can degrade the insulation around motor windings, allowing current to leak to the motor frame.
   • Damaged Motor Power Cable: VFD output cables are subjected to high dV/dT (rate of voltage change) transients, which can stress insulation. Physical damage (chafing, crushing, cuts) during installation or operation, or moisture ingress into conduit and junction boxes, can compromise cable insulation, leading to ground faults.
   • VFD Internal Ground Fault: While less common, a ground fault can originate within the VFD’s output section (e.g., a shorted IGBT to heatsink). If motor and cable insulation tests are clear, an internal VFD issue is highly probable.

   Communication Errors (COMx)

   Communication errors prevent the VFD from receiving commands or sending status information to the control system (PLC, DCS). This results in loss of control, inability to start/stop, or faults indicating a break in the communication link. These errors are common in networked industrial environments adhering to standards such as Modbus RTU (RS-485), Profibus, EtherNet/IP, or PROFINET.

   • Physical Layer Damage: The most frequent cause is damage to the network cabling (e.g., cuts, kinks, worn insulation), loose or improperly terminated connectors, or incorrect wiring (e.g., swapped data lines).
   • Incorrect Network Parameters: Mismatched communication settings between the VFD and the network master (e.g., incorrect Modbus address, baud rate, parity, or stop bits) will prevent successful data exchange.
   • Electromagnetic Interference (EMI): VFDs generate significant EMI. Poor cable shielding, inadequate grounding practices, improper routing of control wiring near power cables, or ground loops can induce noise onto communication lines, corrupting data and causing communication errors.
   • Network Termination Issues: In serial communication networks like RS-485 (Modbus RTU), proper termination resistors (typically 120 Ω) are required at both ends of the bus to prevent signal reflections. Missing or incorrectly placed termination can cause intermittent or complete communication failure.

   Step-by-Step Resolution Procedures

   Resolution: Overcurrent Faults

   1. (LOTO) Verify Mechanical Load: Systematically disconnect the motor from the driven equipment. Attempt to rotate the motor shaft manually; it should turn freely. Inspect driven equipment for binding, seizing bearings, or obstructions.
   2. (LOTO) Inspect Motor & Cables: Conduct insulation resistance tests on motor windings and output cables as detailed in the Fault-Cause Matrix. If insulation resistance is below 1.0 MΩ, isolate the fault. If the motor is the fault, consider drying, rewinding, or replacing. If the cable is the fault, replace with VFD-rated shielded cable, ensuring proper grounding of the shield.
   3. Adjust VFD Parameters:
      1. Verify VFD motor nameplate data (FLA, voltage, RPM) precisely matches the actual motor.
      2. Increase acceleration/deceleration ramp times by 25-50% if the fault occurs during these periods, particularly for high-inertia loads. Monitor current during ramps to optimize.
      3. Review current limit settings; ensure they are appropriate for the application.
   4. Verify VFD Cooling: Inspect VFD cooling fans for operation and cleanliness. Clean or replace dirty air filters and clear any obstructions to airflow. Ensure ambient temperature around VFD is within manufacturer specifications (e.g., typically <40°C or 104°F).
   5. (LOTO) Inspect VFD Output Stage: If previous steps yield no fault, a VFD internal fault is probable. Visual inspection for burnt components or discoloration is advised. This often necessitates VFD replacement or service by a qualified VFD technician.

   Resolution: Overvoltage Faults

   1. Verify Input Line Voltage: Measure and log input line voltage over time. If consistently high or experiencing significant transients (>10% nominal), investigate utility supply or adjust transformer tap settings.
   2. Adjust Deceleration Ramp Time: For regenerative loads, increase the deceleration ramp time in the VFD parameters. This slows the energy feedback rate, allowing more time for the motor to coast down.
   3. (LOTO) Inspect Braking Resistor/Unit:
      1. Measure the resistance of the braking resistor. It must match the manufacturer’s specified value (e.g., 25 Ohms +/- 5%). Replace if open circuit or significantly out of tolerance.
      2. Verify the braking unit’s control circuitry if applicable. Check for proper gate signals to the internal transistors.
   4. Install/Size Braking Components: If regenerative energy is consistently an issue, ensure the braking resistor and/or braking unit are correctly sized for the application’s energy requirements. Consider adding a dynamic braking unit for severe regenerative loads.

   Resolution: Ground Faults

   1. (LOTO) Isolate and Test Motor: Disconnect all three motor leads (T1, T2, T3) from the VFD output. Perform an insulation resistance test on the motor windings to ground at 500V or 1000V. Resistance must be >1.0 MΩ. If not, the motor is faulty.
   2. (LOTO) Isolate and Test Motor Cable: If the motor passes, perform an insulation resistance test on the motor output cable (from VFD terminals to motor side of disconnection point) to ground. Resistance must be >1.0 MΩ. If not, the cable is faulty.
   3. Repair/Replace Faulty Component: Based on isolation, repair or replace the compromised motor or VFD output cable. Ensure replacement cables are VFD-rated (e.g., conforming to NEMA MG 1 Part 30/31 for surge protection) and properly shielded, with the shield grounded at the VFD end.
   4. (LOTO) Inspect VFD: If both motor and cable test clear, the ground fault originates within the VFD. A qualified VFD technician should inspect the drive for internal component failures (e.g., IGBT short to heatsink).

   Resolution: Communication Errors

   1. (LOTO) Inspect Physical Layer: Visually inspect the communication cable for physical damage. Verify all connections at the VFD, control panel, and master device are secure and correctly wired according to manufacturer specifications (e.g., ‘A’ to ‘A’, ‘B’ to ‘B’ for RS-485). Use a continuity tester for damaged cables. Replace damaged cable with appropriate industrial-grade communication cable.
   2. Verify Network Parameters: Use the VFD’s HMI or programming software to confirm all communication parameters (address, baud rate, parity, stop bits) exactly match the settings configured in the network master (PLC, DCS).
   3. Check Network Termination: For serial bus networks (e.g., RS-485), ensure 120 Ω termination resistors are installed ONLY at the physical ends of the network bus. Verify resistance across the data lines at the VFD (with power off and disconnected from master) to confirm correct termination.
   4. Address EMI:
      1. Ensure VFD power and motor cables are properly shielded and grounded (shield grounded at both ends for motor cables, single end for communication cables if susceptible to ground loops, or according to specific network standard).
      2. Route communication cables separately from power cables, maintaining minimum separation distances (e.g., 12 inches / 30 cm for parallel runs).
      3. Verify proper grounding of the VFD and control system components according to IEEE and NFPA standards.
   5. Monitor Network Traffic: Utilize network diagnostic tools (e.g., ProfiTrace for Profibus, Wireshark with appropriate adapter for Ethernet/IP) to monitor traffic, identify corrupted packets, and diagnose subtle communication issues.

   Preventive Measures

   Proactive strategies are essential to minimize VFD fault occurrences and extend equipment life.

   Root Cause	Prevention Strategy	Monitoring Method	Recommended Interval
   Mechanical Overload	Properly size motor/VFD to application; lubricate driven equipment per OEM schedule; regular bearing inspection.	Motor current trend analysis (VFD logs), vibration analysis, thermal imaging of motor/bearings.	Monthly (current), Quarterly (vibration/thermal), Bi-annually (lubrication/inspection).
   Motor Electrical Degradation	Implement motor insulation testing program; ensure proper environmental protection (IP rating); use VFD-rated motors/cables.	Megohmmeter testing of motor/cables; partial discharge monitoring (advanced).	Annually (Megohmmeter), Continuous (VFD ground fault monitoring).
   VFD Parameter Mismatch	Standardize VFD programming procedures; regular parameter audits; robust change management.	Compare VFD parameters to documented baseline; review fault logs for consistent trip conditions.	Annually or after any VFD/motor replacement/maintenance.
   Regenerative Braking	Properly size braking resistors/units; optimize deceleration ramps.	Monitor VFD DC bus voltage and braking resistor temperature (if instrumented).	Continuous (DC bus), Quarterly (resistor inspection/thermal imaging).
   EMI / Communication Issues	Adhere to IEEE/NFPA grounding and shielding practices; separate power/control wiring; use shielded communication cables.	Oscilloscope for signal integrity; network diagnostic tools; visual inspection of cabling.	Annually (physical inspection), As needed (signal integrity check).

   Spare Parts & Components

   Maintaining a critical spares inventory is crucial for rapid recovery from VFD-related faults. Always consult OEM documentation for precise part numbers and specifications.

   Part Description	Specification (Example)	When to Replace	UNITEC Category
   VFD, Low Voltage (up to 690V)	VFD, 10 HP, 480V, IP20, e.g., Siemens SINAMICS G120 (PN: 6SL3210-1PE13-8UL0)	Catastrophic internal failure (e.g., multiple IGBT failures), irreparable control board damage, end-of-life.	Motor Control Systems
   Braking Resistor	5 kW, 25 Ohm, IP20, e.g., ABB NEMA 1 (PN: 3AXD10000000392)	Open circuit, resistance deviation >10%, visible charring or mechanical damage.	Braking Systems & Components
   Line/Load Reactor	3 Phase, 480V, 10A, 3% Impedance, e.g., Schaffner RN 103-10-02 (PN: RN103-10-02)	Overheating (discoloration), winding insulation breakdown, audible buzzing/vibration.	Power Quality & Filtering
   Fuses (Input/DC Bus)	UL Class J, 30A, 600V AC/DC, e.g., Eaton Bussmann FRS-R-30 (PN: FRS-R-30)	Blown due to overcurrent/short circuit. ALWAYS replace with exact type and rating.	Electrical Protection Devices
   Motor (3-Phase Induction)	10 HP, 1800 RPM, 480V, TEFC, NEMA Premium Efficient, e.g., Baldor M3615T (PN: M3615T)	Irreparable winding fault, severe bearing damage (shaft play >0.005 inches), catastrophic mechanical failure.	Industrial Electric Motors
   VFD Rated Motor Cable	12 AWG, 3 Conductor + Ground, Shielded, Tinned Copper, e.g., Belden 29501 (PN: 29501)	Insulation damage (cuts, chafing), visible fraying, significant water ingress, EMI issues.	Industrial Cabling & Wire
   Cooling Fans (VFD)	Manufacturer-specific replacement fan module, e.g., for Allen-Bradley PowerFlex 755 (PN: 20G1C021A0C0AAANN)	Non-operational, excessive noise, reduced airflow, fan fault indication from VFD.	VFD Spare Parts & Accessories

   For a complete range of VFD-related components and industrial spares, visit the UNITEC-D E-Catalog.

   References

   • ANSI/NEMA MG 1-2021: Motors and Generators
   • NFPA 70E: Standard for Electrical Safety in the Workplace
   • IEEE Std 519-2014: IEEE Recommended Practice and Requirements for Harmonic Control in Electric Power Systems
   • IEEE Std 43-2000: Recommended Practice for Testing Insulation Resistance of Rotating Machinery
   • OEM Variable Frequency Drive Installation and Maintenance Manuals (e.g., Siemens, Rockwell Automation, ABB)