Abstract The Leadshine L7 series AC servo drives are crucial components in the field of industrial automation. The startup display sequence reflects the device’s initialization status and operational readiness. This paper provides an in-depth analysis of the phenomenon where users observe a brief display of “1.d002” followed by a switch to “00ST,” indicating a normal initialization process. By interpreting the manual, safety precautions, and incorporating online resources from similar EL7 series, it explores the meanings of display codes, diagnostic methods, potential causes, and optimization strategies, aiming to offer comprehensive guidance to engineers and technicians.
Introduction In modern industrial automation systems, servo drives play a pivotal role. The Leadshine L7 series AC servo drives utilize the latest DSP from Texas Instruments (TI), featuring high integration and reliability. Users often encounter startup display issues, such as the display showing “1.d002” briefly after power-on, followed by a switch to “00ST.” This paper centers on this phenomenon, conducting a systematic analysis by combining excerpts from the user manual and online resources, aiming to assist users in understanding the technical implications of the display sequence and providing practical diagnostic steps.
Servo Drive Fundamentals
Basic Principles
Servo drives drive servo motors to achieve precise motion by receiving command signals from an upper-level controller. The fundamental principles include triple-loop control (position loop, speed loop, and current loop), with PID algorithms at the core.
L7 Series Characteristics
The L7 series belongs to AC servo drives, supporting 220VAC input and a wide power range. The manual emphasizes that improper operation can lead to severe consequences, and users must adhere to safety precautions.
Key Components and Initialization
The key components of a servo system include the drive, motor, and encoder. The drive integrates a DSP processor, and the initialization process involves self-tests, parameter loading, and status monitoring.
Display Panel Basics
The display panel employs a seven-segment LED digital tube, supporting status display, parameter settings, and alarm prompts. Understanding these codes is crucial for diagnosing device status.
Control Modes and Parameter Settings
Servo drives offer control modes including position, speed, and torque modes. Parameter settings are achieved through panel buttons or MotionStudio software.
Safety Guidelines
The manual stresses that product storage and transportation must comply with environmental conditions, and user modifications will void the warranty.
Overview of the L7 Series
Product Features and Updates
The Leadshine L7 series is a fully digital AC servo drive, utilizing TI DSP, supporting stiffness tables, inertia identification, and vibration suppression. The version has evolved from V1.00 to V2.10 with continuous updates.
Application Areas and Manual Structure
The L7 series finds wide applications in PLC control, robotic arms, and other fields. The manual structure covers the preface, safety matters, specifications, installation, wiring, commissioning, and maintenance.
Wiring and Version Descriptions
Wiring includes power, motor, encoder, and I/O ports. The version description indicates program compatibility and content updates.
Display Panel in Detail
Operation Interface and Key Functions
The L7 drive’s operation interface consists of a 6-digit LED digital tube and 5 keys for status display and parameter settings.
Initialization and Monitoring Mode Codes
Upon power-on, the panel first displays initialization codes. “1.d002” may be a custom or transient display, and switching to “00ST” indicates a standby state. Monitoring mode codes include position deviation, motor speed, etc.
Alarm Code Interpretation
Alarm codes start with “Er,” and the absence of “Er” indicates normal operation.
Diagnostic Analysis
Core Phenomenon Interpretation
The display showing “1.d002” briefly followed by a switch to “00ST” is a normal sequence. The initialization process includes self-tests and parameter loading.
Potential Causes Explored
Potential causes include normal boot-up, configuration influences, and external factors.
Diagnostic Steps and Methods
Diagnostic steps include checking the display history, software verification, and factory reset.
Troubleshooting
Non-Normal Situation Exclusion Methods
If non-normal, exclusion methods include power supply checks, wiring verification, parameter resets, and software tuning.
Common Faults and Solutions
Common faults such as overcurrent and overload are unrelated to the display sequence.
Applications and Optimization
Case Studies: CNC Machine Tools and Robotic Arms
Case 1: A CNC machine tool uses the L7 to control axes, and a normal startup sequence ensures precision. Case 2: A robotic arm in bus mode uses EtherCAT synchronization to avoid delays.
Optimization Strategies and Future Trends
Optimization strategies include adjusting control modes and vibration suppression. Future trends involve integrating AI tuning.
Conclusion The transition from “1.d002” to “00ST” indicates a normal state. Mastering diagnostic methods can enhance application efficiency. It is recommended to refer to the manual and technical support to ensure stable system operation.
The EST900 series inverter from Yiste, as a high-performance vector inverter, is widely applied in the control and speed regulation of three-phase asynchronous motors. This article, based on the official manual, will elaborate in detail on its operation panel functions, parameter setting methods, external terminal control and speed regulation implementation, as well as handling measures for common fault codes, helping users quickly master the usage skills.
I. Introduction to Operation Panel Functions and Parameter Settings
(A) Overview of Operation Panel Functions
The EST900 series inverter comes standard with an LED operation panel, which offers a variety of functions:
Status Monitoring: It can display key information such as operating frequency, current, voltage, and fault codes in real time.
Parameter Setting: It supports viewing and modifying functional parameters.
Operation Control: Control commands such as start, stop, and forward/reverse rotation can be executed through the panel.
Indicator Lights: It is equipped with indicator lights including RUN (operation), LOCAL/REMOT (control source), FWD/REV (direction), and TUNE/TC (tuning/torque/fault), which visually reflect the equipment status.
(B) Factory Parameter Settings
During debugging or when parameters are in disarray, a factory reset operation can be performed:
Steps:
Enter the FP – 01 parameter.
Set it to 1 (restore factory parameters, excluding motor parameters).
Press the ENTER key to confirm.
Wait for the display to restore, indicating parameter initialization is complete.
Notes:
FP – 01 = 2 can clear fault records and other information.
FP – 01 = 4 can back up the current parameters.
FP – 01 = 501 can restore the backed-up parameters.
(C) Password Setting and Clearing
To prevent misoperation, a user password can be set:
Setting a Password:
Enter FP – 00 and set it to a non-zero value (e.g., 1234).
After exiting, the password needs to be entered when accessing parameters again.
Clearing a Password:
Set FP – 00 to 0.
(D) Parameter Access Restrictions
Parameter access can be restricted in the following ways:
Parameter Group Display Control:
Set the FP – 02 parameter to control whether Group A and Group U parameters are displayed.
For example, setting it to “11” can hide some parameter groups to prevent mismodification.
Prohibition of Modification during Operation:
Some parameters marked with “★” cannot be modified during operation and need to be set after shutdown.
II. External Terminal Forward/Reverse Rotation Control and Potentiometer Speed Regulation
(A) External Terminal Forward/Reverse Rotation Control
Note: If a three-wire control system is used, set F4 – 11 = 2 or 3 and cooperate with other DI terminals.
(B) External Potentiometer Speed Regulation
Wiring Terminals:
+10V: Positive pole of potentiometer power supply
GND: Negative pole of potentiometer power supply
A11: Analog voltage input (0 – 10V)
Parameter Settings: | Parameter Code | Name | Setting Value | Description | | —- | —- | —- | —- | | F0 – 03 | Main Frequency Command Selection | 2 | A11 | | F4 – 13~F4 – 16 | A11 Curve Settings | Adjust according to actual conditions | Minimum/maximum input corresponds to frequency |
Tip: It is recommended that the potentiometer resistance be between 1kΩ and 5kΩ to ensure that the current does not exceed 10mA.
III. Common Fault Codes and Handling Methods
The EST900 series inverter has a comprehensive fault diagnosis function. The following are common faults and their handling methods:
(A) Overcurrent Faults
Fault Code
Name
Possible Causes
Handling Measures
Err02
Acceleration Overcurrent
Motor short circuit, too short acceleration time
Check motor insulation, increase acceleration time
Err03
Deceleration Overcurrent
Short deceleration time, large load inertia
Increase deceleration time, install a braking resistor
Err04
Constant-speed Overcurrent
Load mutation, mismatched motor parameters
Check the load, perform motor tuning again
(B) Overvoltage Faults
Fault Code
Name
Possible Causes
Handling Measures
Err05
Acceleration Overvoltage
High input voltage, external force during acceleration
Check power supply voltage, enable overvoltage suppression
Err06
Deceleration Overvoltage
Short deceleration time, energy feedback
Increase deceleration time, install a braking unit
Err07
Constant-speed Overvoltage
External force dragging during operation
Check the mechanical system, enable overvoltage suppression
(C) Other Common Faults
Fault Code
Name
Possible Causes
Handling Measures
Err09
Undervoltage Fault
Low power supply voltage, rectifier bridge fault
Check the power supply, measure the bus voltage
Err10
Inverter Overload
Excessive load, undersized selection
Check the load, replace with a higher-power inverter
Err11
Motor Overload
Excessive motor load, improper protection parameter setting
Adjust the F9 – 01 motor overload gain
Err14
Module Overheating
Poor heat dissipation, fan fault
Clean the air duct, replace the fan
Err16
Communication Fault
Wiring error, improper parameter setting
Check the communication line, set FD group parameters
(D) Fault Reset Methods
Press the STOP/RESET key on the panel.
Set a DI terminal to the “Fault Reset” function (F4 – xx = 9).
Write “2000H = 7” through communication.
Power off and restart (wait for more than 10 minutes).
IV. Conclusion
The Yiste EST900 series inverter is powerful and flexible in operation, capable of adapting to various industrial scenarios. Through the introduction in this article, users can master the following key contents:
Basic usage methods of the operation panel and parameter setting skills.
How to control and regulate the speed of the motor using external terminals and a potentiometer.
Diagnostic ideas and handling skills for common faults.
Effective use of password management and parameter protection mechanisms. During actual use, it is recommended that users strictly follow the manual specifications for wiring and parameter setting, and regularly carry out maintenance work to ensure the long-term stable operation of the equipment.
In industrial automation systems, frequency inverters are the key components for controlling motor speed and torque. The operational stability of an inverter directly determines the reliability of an entire production line. Among numerous industrial drive products, the Emerson EV2000 series is well recognized for its robust performance, precise vector control, and adaptability to a wide range of applications — from pumps and fans to textile machines and conveyors.
However, during field operation or long-term use, some users may encounter a display message reading “P.oFF” on the inverter’s LED panel. At first glance, this may look like a severe fault such as a power module failure or control board defect. In reality, “P.oFF” is not a typical fault alarm, but rather a protective shutdown state known as “Undervoltage Lockout (LU).”
This article provides a comprehensive technical analysis of the P.oFF condition in the Emerson EV2000 inverter. It integrates official documentation, field diagnostic data, and maintenance experience to explain its causes, triggering mechanism, troubleshooting methods, and preventive measures.
2. Technical Definition of P.oFF
According to the official EV2000 User Manual:
“When the DC bus voltage drops below the undervoltage threshold, the inverter outputs a protection signal and displays ‘P.oFF’ on the LED panel.”
This statement reveals the essence of the fault: P.oFF occurs when the inverter’s internal DC bus voltage (DC link voltage) falls below a safe limit.
Normally, the rectifier circuit inside the EV2000 converts three-phase AC power (380V ±10%) into DC voltage of approximately 540–620 VDC. When the input power drops, the rectifier is damaged, the DC bus capacitors age, or the braking unit malfunctions, the DC voltage may fall below the predefined undervoltage threshold (around 300 VDC). At that point, the inverter automatically enters a protective lockout to prevent unstable operation or component damage.
It is important to note that unlike “E” code faults (such as E001 – overcurrent, E002 – overvoltage), P.oFF does not trigger a trip alarm. Instead, the inverter temporarily disables output until the voltage returns to normal.
3. Electrical Mechanism Behind the P.oFF State
To fully understand this phenomenon, we must look into the EV2000’s main power structure.
3.1 Composition of the Main Circuit
The inverter’s main power path includes the following key components:
Input terminals (R, S, T): three-phase AC supply
Rectifier bridge module: converts AC to DC
DC bus capacitors: stabilize and filter DC voltage
Braking unit and resistor: absorb regenerative energy from motor deceleration
IGBT inverter bridge: converts DC back into PWM-controlled AC output
3.2 How Undervoltage Lockout Is Triggered
The control board constantly monitors the DC bus voltage. When it detects a voltage lower than the threshold (typically around 300–320 VDC), it executes the following logic sequence:
Disables IGBT outputs — halting motor operation
Displays “P.oFF” on the panel
Waits in standby mode until the DC bus recovers above the normal level (typically >380 VDC)
This mechanism is a preventive protection system designed to shield the inverter from grid voltage sags, capacitor discharges, or transient faults. Thus, P.oFF is not an error; it is an intentional safety lock.
4. Root Causes of the P.oFF Condition
From field experience and manual analysis, the following are the most common reasons for P.oFF to appear.
(1) Input Power Problems
Voltage imbalance between the three input phases (>3%)
Mains voltage below 320V AC or fluctuating severely
Loose power terminals or poor contact
Excessive line voltage drop due to long cable runs
These account for nearly half of all P.oFF cases and are primarily related to unstable supply power.
(2) Faulty Rectifier Module
A damaged or open diode inside the rectifier bridge reduces the DC bus voltage, often accompanied by audible hum or irregular current flow.
(3) Aged or Leaky DC Capacitors
Over time, electrolytic capacitors lose capacitance and their internal ESR increases. This weakens their ability to smooth the DC voltage, resulting in a temporary drop when load or braking energy fluctuates — enough to trigger an undervoltage lock.
In units running for 3–5 years, this is one of the most frequent root causes.
(4) Braking Circuit Malfunction
A shorted braking unit or resistor constantly discharges the DC bus, causing the voltage to collapse. To verify, disconnect the braking circuit and power on again — if P.oFF disappears, the issue lies in that circuit.
(5) Momentary Power Interruptions
Factories with welding machines, compressors, or heavy inductive loads can experience grid sags. If the inverter’s “Ride-through” (instantaneous power-loss recovery) function is disabled, any short voltage dip may cause P.oFF.
5. Systematic Troubleshooting Process
To effectively diagnose and repair the P.oFF issue, engineers can follow a step-by-step workflow:
Step 1 – Observe the Symptom
Panel displays “P.oFF”
No “E” fault code is present
Motor stops automatically
After a few minutes, the inverter may restart on its own
If these conditions match, the inverter is in undervoltage lockout mode.
Step 2 – Measure Input Power
Use a multimeter to measure R–S–T line voltages:
Normal range: 380–440 V
Below 360 V or phase difference >10 V → adjust power source or connections
Step 3 – Measure DC Bus Voltage
Check voltage across (+) and (–) terminals:
Normal: 540–620 VDC
Below 300 VDC → rectifier or capacitor failure
Step 4 – Isolate the Braking Circuit
Disconnect the braking resistor/unit and test again. If the problem disappears, replace or repair the braking components.
Step 5 – Test the DC Capacitors
After power-off, measure capacitance and discharge rate:
If voltage drops to zero within a few seconds, leakage is severe
Replace if measured capacitance is <70% of rated value
Step 6 – Verify Control Power
Check auxiliary voltages (P24, +10V, +5V). Low control supply may cause false P.oFF detection.
6. Repair and Recovery Procedures
Once the root cause has been identified, proceed with the following repair actions:
Stabilize Power Supply
Re-tighten input terminals
Ensure voltage balance across all three phases
Install an AC reactor or voltage stabilizer if necessary
Replace Faulty Components
Replace aged electrolytic capacitors as a set
Replace damaged rectifier modules with same-rated units
Inspect Braking Circuit
Measure P–PR resistance for shorts
Ensure thermal relay contacts (TH1, TH2) are functioning
Enable Ride-through Function The EV2000 allows short-duration undervoltage ride-through; enabling this can prevent false P.oFF triggers caused by brief voltage dips.
Recommission and Verify
Power up and observe DC voltage stability
Run at light load for 10 minutes, then gradually increase load
Once the display shows “RDY”, the inverter is ready for normal operation
7. Preventive and Optimization Measures
To avoid recurring undervoltage lockouts, adopt the following best practices:
7.1 Power-Side Protection
Use proper circuit breakers or fuses rated for inverter service
Add a DC reactor for harmonic suppression and voltage stabilization
Use thicker power cables if installation distance is long
7.2 Environmental Control
Maintain cabinet temperature below 40°C
Ensure clean airflow; avoid dust, oil, or moisture buildup
Regularly clean cooling fans and filters
7.3 Periodic Maintenance
Measure DC bus voltage and capacitor health yearly
Replace capacitors after ~3 years of continuous operation
Test rectifier module every 5 years or after heavy load operation
7.4 Parameter Optimization
Set appropriate acceleration/deceleration times to avoid current spikes
Enable AVR (Automatic Voltage Regulation) and Current Limit functions
Review output terminal settings in parameter group F7 to prevent incorrect logic assignments
8. Case Study: Intermittent P.oFF on a 22kW Fan Drive
Background: A 22kW EV2000 inverter controlling a centrifugal fan exhibited intermittent P.oFF shutdowns after six months of operation.
Symptoms:
Occurred around 45 Hz operation
The inverter automatically recovered after a few minutes
Mains voltage appeared normal
Diagnosis:
DC bus voltage fluctuated between 520–550V with periodic dips
Two electrolytic capacitors found bulging and degraded
Replaced capacitors → inverter operated normally
Conclusion: The failure was caused by aged capacitors reducing DC storage capacity, resulting in transient undervoltage. This is a classic “aging-induced P.oFF” scenario.
9. Conclusion
The P.oFF message on Emerson EV2000 inverters is not a random or critical failure, but a designed protective feature to safeguard the drive system when DC bus voltage drops abnormally.
Understanding its mechanism helps engineers correctly differentiate between true hardware faults and temporary protective lockouts. By following a structured diagnostic approach — from input power verification to capacitor and braking circuit inspection — technicians can quickly restore normal operation.
Furthermore, implementing preventive maintenance and enabling built-in functions such as ride-through and AVR can significantly enhance long-term reliability.
As the design philosophy of Emerson EV2000 suggests:
“Reliability is not accidental — it begins with every small detail of protection.”
From Overheated IGBT Modules to Full System Recovery
1. Introduction
In modern screw air compressors, the variable frequency drive (VFD) is the core component responsible for controlling motor speed and optimizing power consumption. The Chmairss VGS30A compressor, equipped with a 22 kW VEMC inverter, uses variable-speed control to maintain constant discharge pressure while achieving high energy efficiency.
However, after long-term operation, one of the most common issues that field engineers encounter is the “Err14 – Module Overheat” fault on the VEMC inverter. This error not only causes system shutdown but also indicates potential thermal imbalance or hardware degradation inside the inverter.
This article provides a comprehensive technical explanation and a complete repair workflow — from understanding the root cause of Err14, diagnosing the issue step-by-step, to repairing and preventing future failures. It is based on real-world field data from a VGS30A compressor maintenance case.
2. Fault Symptoms and Display Information
(1) On the Main Control Panel (HMI)
The compressor controller repeatedly shows the following message:
STATE: MOTOR INV FAULT
CODE: 00014
Multiple entries appear in the fault history list (024–028), all labeled “MOTOR INV FAULT.”
(2) On the VEMC Inverter Panel
The inverter LED display reads:
Err14
The red alarm indicator is on, and the motor cannot start. Once the contactor closes, the inverter trips immediately.
(3) PLC and System Reaction
The PLC detects the inverter fault signal and sends a stop command to the entire compressor. Frequency display freezes at 0.0 Hz, power output shows 0.0 kW, and total run time stops accumulating.
3. Understanding the “Err14” Code — Module Overheat Fault
The inverter continuously monitors the IGBT module temperature via an NTC thermistor attached to the power module. This analog signal is converted to a voltage and fed to the control CPU through an A/D converter.
Normal temperature range: 25 °C – 75 °C
Warning level: ~85 °C
Trip threshold: ~95 °C
If the module temperature exceeds the limit or the temperature signal becomes abnormal (open circuit, short circuit, or unrealistic value), the inverter will immediately shut down to protect the IGBT module. The control CPU disables PWM output and reports Err14.
4. Common Root Causes of Err14
Based on maintenance experience and field diagnostics, there are five main categories of causes for Err14:
Category
Cause
Description
🌀 Cooling failure
Fan blocked or not running
Dust, oil mist, or worn bearings stop the fan, reducing heat dissipation efficiency.
🌡️ Ambient overheating
Poor cabinet ventilation
When internal cabinet temperature exceeds 45 °C, the module’s junction temperature rises quickly.
🔌 NTC thermistor fault
Broken, oxidized, or loose sensor
The temperature signal becomes unstable or reads as “overheated” even at normal temperature.
⚡ IGBT module damage
Aging or partial short circuit
Localized overheating triggers overtemperature alarm even under light load.
🧭 Control board error
Faulty sampling or amplifier circuit
A/D converter malfunction misreads temperature as extreme value, causing false alarm.
5. Step-by-Step Diagnostic Procedure
Step 1 – Inspect the Cooling Fan and Air Duct
Power on the inverter and check whether the internal cooling fan starts automatically.
If the fan does not spin, measure the voltage at the fan terminals (usually DC 12 V or DC 24 V).
Voltage present but fan not spinning → fan motor failure.
No voltage → main control board output failure.
Clean the air duct, dust filter, and heat-sink fins thoroughly.
Step 2 – Check Cabinet Temperature
Use an infrared thermometer to measure temperature inside the control cabinet.
If it exceeds 45 °C, install additional exhaust fans or ventilation openings.
Avoid placing the cabinet near heat sources (e.g., compressor discharge pipe).
Step 3 – Test the NTC Thermistor
Power off and wait at least 10 minutes for discharge.
Remove the drive or power board.
Measure resistance between NTC terminals (typically around 10 kΩ at 25 °C).
Heat the sensor slightly with a hot-air gun — the resistance should decrease with rising temperature.
If resistance is fixed or open circuit → replace the thermistor.
Step 4 – Check the IGBT Power Module
Use a multimeter diode-test function to check each phase (U, V, W) to positive/negative bus.
Any shorted or low-resistance reading (< 0.3 Ω) indicates IGBT damage.
Verify that the power module is tightly clamped to the heat sink.
Reapply high-quality thermal grease (e.g., Dow Corning 340) if dried or cracked.
Step 5 – Check the Control Board Temperature Circuit
If all above components are normal but Err14 remains:
Inspect connector pins (often CN6 or CN8) for oxidation or loose contact.
Use an oscilloscope to observe temperature signal voltage (should decrease gradually as temperature rises).
Constant 0 V or 5 V output → indicates A/D converter or amplifier failure.
Replace the entire driver/control board if signal circuit is defective.
6. Case Study — Actual Field Repair of a VGS30A Compressor
Equipment details:
Model: Chmairss VGS30A
Inverter: VEMC 22 kW
Total runtime: 7 303 hours
Ambient temperature: ~38 °C
Fault: Err14 appears within seconds after startup; fan not rotating
Inspection and Findings
Component
Result
Action Taken
Cooling fan power
24 V output normal
Fan motor seized → replaced
Air duct
Heavy dust accumulation
Cleaned thoroughly
Thermistor
9.7 kΩ at 25 °C
OK
IGBT module
All phases normal
OK
Thermal grease
Completely dried
Reapplied new grease
Control board
No oxidation or damage
OK
After cleaning and replacing the fan, the inverter started normally. After 30 minutes of continuous operation, module temperature stabilized at 58 °C, confirming successful repair.
7. Electrical and Thermal Theory Behind Err14
(1) Power Loss and Junction Temperature
The IGBT’s heat generation consists of conduction and switching losses: [ P_{loss} = V_{CE} \times I_C + \tfrac{1}{2}V_{CE} I_C f_{sw} (t_{on}+t_{off}) ] If heat cannot be transferred efficiently to the heat sink, junction temperature (Tj) rises sharply, increasing conduction loss — a positive feedback that can lead to thermal runaway and module destruction.
(2) Importance of Thermal Interface
The thermal resistance (Rθjc) between IGBT and heat sink determines how quickly heat is removed. Dried or aged thermal compound increases resistance several times, leading to localized hot spots even when load current is normal.
(3) Protection Logic Inside VEMC Drive
The inverter CPU continuously samples the temperature signal:
Below 0.45 V (≈ 95 °C): trigger Err14 and shut down PWM output.
Above 0.55 V (≈ 85 °C): allow reset condition.
Open circuit: immediate fault lockout, manual reset required.
8. Preventive Maintenance Recommendations
Task
Frequency
Recommended Action
Clean cooling fan and duct
Every 3 months
Use compressed air to remove dust and oil residue.
Replace thermal grease
Every 12 months
Apply fresh silicone-based compound between IGBT and heat sink.
Check ambient temperature
Continuous
Ensure cabinet stays below 40 °C.
Tighten wiring terminals
Every 6 months
Prevent loose or oxidized connections.
Record temperature log
Each service
Document operating temperature trend.
Inspect power module
Upon abnormal fault
Use thermal camera to detect uneven heating.
Regular maintenance can extend inverter lifetime by 30–50 %, reduce downtime, and prevent expensive module failures.
9. Temporary Reset for Diagnostic Verification
If you suspect a false alarm:
Power off and wait at least 10 minutes for cooling.
Power on and press STOP/RESET.
If Err14 reappears immediately → likely sensor or circuit fault.
If it occurs after several minutes of operation → genuine overheating issue.
10. Troubleshooting Flow (Text Version)
Err14 Detected →
↓
Check Cooling Fan Running?
├─ No → Measure fan supply → replace fan if needed
└─ Yes →
↓
Is Ambient Temperature >45°C?
├─ Yes → Improve ventilation
└─ No →
↓
Measure NTC Thermistor Resistance
├─ Abnormal → Replace NTC
└─ Normal →
↓
Inspect IGBT Module & Thermal Grease
├─ Abnormal → Reapply grease / replace module
└─ Normal →
↓
Replace Driver Board (temperature circuit failure)
11. Practical Notes and Safety Reminders
Always discharge DC bus capacitors before touching power terminals (wait >10 minutes).
When replacing thermal grease, ensure no air gaps between module and heat sink.
If replacing the IGBT module, apply torque evenly and use original insulation pads.
Keep cabinet filters clean and avoid placing the compressor near exhaust heat or walls.
Use infrared thermometer to monitor heat sink temperature during first startup after repair.
12. Lessons Learned
This case of the Chmairss VGS30A compressor with VEMC inverter Err14 demonstrates the critical role of thermal management in power electronics. Although the message “Module Overheat” seems simple, it reflects a complex interaction between cooling airflow, thermal interface condition, and signal detection circuits.
Field statistics show:
About 70 % of Err14 faults are resolved by cleaning the cooling path, replacing fans, or re-greasing the module.
The remaining 30 % involve circuit faults or component failures (NTC or driver board).
Understanding these mechanisms allows engineers to diagnose quickly, repair efficiently, and reduce costly downtime.
13. Conclusion
The Err14 (Module Overheat) fault is not merely an alarm — it is the inverter’s self-protection mechanism preventing irreversible IGBT damage. Proper analysis requires both electrical and thermal reasoning. By following the structured diagnostic steps in this guide — inspecting the fan, air duct, thermistor, power module, and control board — maintenance engineers can isolate the root cause systematically.
Regular preventive maintenance, good ventilation, and periodic internal cleaning are the best strategies to ensure long-term reliability of VEMC inverters in air compressor applications.
The DOVOL DV950E series permanent magnet synchronous frequency converter is a general-purpose, high-performance current vector frequency converter. It is mainly used to control and adjust the speed and torque of three-phase AC synchronous motors. This guide provides detailed information on the converter’s functional features, operation methods, parameter settings, and troubleshooting, helping users quickly master the skills of using the equipment.
II. Basic Functions and Wiring
Product Main Features
Control Modes: Supports sensorless vector control (SVC), sensor-based vector control (FVC), and V/F control.
Frequency Range: 0 – 500Hz.
Overload Capacity: 150% of the rated current for 60 seconds, 180% of the rated current for 3 seconds.
Speed Regulation Range: 1:50 in SVC mode, 1:1000 in FVC mode.
Built-in PID Regulator: Supports process closed-loop control.
Multiple Communication Protocols Supported: Modbus, ProfiBus-DP, CANlink, CANopen.
Electrical Installation Precautions
Main Circuit Wiring: Correctly distinguish between input terminals (R, S, T) and output terminals (U, V, W).
Braking Resistor: Do not connect the braking resistor directly between the DC bus (+) and (-) terminals.
Motor Cable Length: When the motor cable length exceeds 100m, install an AC output reactor.
Grounding: Ensure reliable grounding with a grounding wire resistance of less than 10Ω.
Power Supply Voltage: Before powering on, ensure that the power supply voltage matches the rated voltage of the frequency converter.
III. Operation Panel Usage
Panel Layout and Indicators
RUN: Running status indicator (lights up when in operation).
LOCAL/REMOT: Control mode indicator (off – panel control; on – terminal control; flashing – communication control).
FWD/REV: Forward/reverse rotation indicator (lights up for reverse rotation).
TUNE/TC: Tuning/torque control/fault indicator.
Five-digit LED Digital Display Area.
Function Keys: PRG (programming), ENTER (confirmation), ▲▼ (increase/decrease), ◄ (shift), etc.
Basic Operation Process
Enter the parameter setting mode by pressing the PRG key.
Select the function group using the ▲▼ keys.
Press ENTER to enter the specific parameter setting.
After modifying the parameter value, press ENTER to save it.
Press the PRG key to return to the previous menu.
IV. Core Function Implementation Methods
Motor Forward/Reverse Rotation Control
Method 1: Panel Control
Set P0-02 = 0 (panel command channel).
Set the running direction via P0-09 (0 – same direction; 1 – opposite direction).
Press the RUN key to start and the STOP key to stop.
Method 2: Terminal Control
Set P0-02 = 1 (terminal command channel).
Assign DI terminal functions: P4-00 = 1 (DI1 for forward rotation), P4-01 = 2 (DI2 for reverse rotation).
Control the on/off state of the DI terminals through external switches to achieve forward/reverse rotation.
Method 3: Communication Control
Set P0-02 = 2 (communication command channel).
Send forward/reverse rotation commands through communication (requires a communication card).
Note: To disable reverse rotation, set P8-13 = 1.
Frequency Regulation Methods
Digital Frequency Setting
Set P0-03 = 0 or 1 (digital setting).
Set the preset frequency via P0-08.
During operation, fine-tune the frequency using the panel ▲▼ keys or UP/DOWN terminals.
Analog Frequency Setting
Set P0-03 = 2 (AI1)/3 (AI2)/4 (AI3).
Configure the curve characteristics of the corresponding AI input (P4-13 – P4-27).
Adjust the frequency using an external potentiometer or PLC analog output.
Multi-speed Control
Set P0-03 = 6 (multi-speed instruction).
Assign DI terminals as multi-speed instructions (P4-00 – P4-09 = 12 – 15).
Set the frequency values for each speed segment in the PC group (PC-00 – PC-15).
PID Frequency Regulation
Set P0-03 = 8 (PID).
Configure the PID parameters in the PA group.
Automatically adjust the frequency based on the feedback signal.
Motor Parameter Tuning
No-load Tuning Steps
Ensure that the motor is mechanically decoupled from the load.
Correctly input the motor nameplate parameters (P1-01 – P1-05).
Set P1-37 = 12 (synchronous motor no-load tuning).
Press the RUN key to start tuning (approximately 2 minutes).
The parameters are automatically saved after tuning is completed.
Loaded Tuning Steps
Set P1-37 = 11 (synchronous motor loaded tuning).
Press the RUN key to start tuning.
The parameters are automatically saved after tuning is completed.
Note: Loaded tuning cannot obtain the back electromotive force coefficient, and the control accuracy is slightly lower than that of no-load tuning.
V. Advanced Function Configuration
Frequency Sweeping Function (Textile Applications)
Set PB-00 = 0 (relative to the center frequency) or 1 (relative to the maximum frequency).
Set PB-01 (frequency sweeping amplitude), PB-02 (jump amplitude).
Set PB-03 (frequency sweeping period), PB-04 (triangular wave rise time).
Control the frequency sweeping pause through the DI terminal (P4-xx = 24).
Fixed-length Control
Set DI5 function as length counting input (P4-04 = 27).
Set PB-07 (pulses per meter).
Set PB-05 (preset length).
Assign DO terminals as length arrival signals (P5-xx = 10).
Counting Function
Set DI terminals as counting input (P4-xx = 25) and reset (P4-xx = 26).
Set PB-08 (preset count value), PB-09 (specified count value).
Assign DO terminals as counting arrival signals (P5-xx = 8 or 9).
Timing Control
Set P8-42 = 1 (timing function enabled).
Set P8-44 (timing operation time) or select AI input via P8-43.
The equipment automatically stops after reaching the preset time.
VI. Fault Diagnosis and Handling
Common Fault Codes and Handling
Fault Code
Fault Type
Possible Causes
Handling Methods
Err02
Acceleration Overcurrent
Short acceleration time/heavy load
Extend the acceleration time P0-17/check the mechanical load
Err03
Deceleration Overcurrent
Short deceleration time
Extend the deceleration time P0-18
Err04
Constant-speed Overcurrent
Load突变 (Load mutation)/motor short circuit
Check the motor insulation/adjust the torque limit P2-10
Err09
Undervoltage
Low input voltage/power outage
Check the power supply voltage/set P9-59 for instantaneous power failure without stop
Err11
Motor Overload
Heavy load/undersized motor
Reduce the load/check the rated current setting P1-03
Err14
Module Overheating
High ambient temperature/poor heat dissipation
Improve the heat dissipation conditions/reduce the carrier frequency P0-15
Err20
Encoder Fault
Signal interference/wiring error
Check the encoder wiring/set P2-32 = 0 to disable Z correction
Fault Reset Methods
Panel Reset: Press the STOP/RES key in the fault state.
Terminal Reset: Set the DI terminal function to 9 (fault reset).
Communication Reset: Send a reset command through communication.
Fault Record Inquiry
Recent Fault: Check P9-16 – P9-22.
Second Fault: Check P9-27 – P9-34.
First Fault: Check P9-37 – P9-44.
VII. Maintenance and Upkeep
Daily Inspection
Check if the cooling fan is operating normally.
Check for loose wiring terminals.
Check if the enclosure temperature is abnormal.
Regularly remove dust from the radiator.
Regular Maintenance
Check the appearance of electrolytic capacitors every six months.
Check the insulation resistance annually (measure after powering off).
Replace the cooling fan every 2 years (depending on the operating environment).
Parameter Backup
Set PP-01 = 4 (backup user parameters).
To restore, set PP-01 = 501.
Restore to factory settings: PP-01 = 1.
VIII. Safety Precautions
Do not open the cover when powered on. After powering off, wait for 10 minutes before performing wiring operations.
Do not connect the braking resistor directly to the DC bus.
Perform an insulation check on the motor before the first use (≥5MΩ).
Derate the equipment when the altitude exceeds 1000m (derate by 1% for every 100m).
Derate the equipment when the ambient temperature exceeds 40℃ (derate by 1.5% for every 1℃).
Do not install capacitors or surge suppressors on the output side of the frequency converter.
This guide provides a detailed introduction to the various function implementation methods of the DV950E frequency converter. When using it in practice, please select the appropriate configuration method according to the specific application scenario. For complex application scenarios, it is recommended to contact the manufacturer’s technical support for more professional guidance.
Frequency range limitation: F0-10 = 50.00Hz, F0-12 = 50.00Hz, F0-14 = 0.00Hz.
III. Fault Diagnosis and Handling
3.1 Common Fault Codes and Solutions
Fault Code
Fault Type
Possible Causes
Solutions
ERR02
Acceleration Overcurrent
Load mutation, short acceleration time
Check the load, increase the acceleration time F0-17
ERR03
Deceleration Overcurrent
Short deceleration time, large load inertia
Increase the deceleration time F0-18, install a braking resistor
…
…
…
…
ERR20
Encoder Fault
PG card fault, wiring error
Check the encoder wiring, set the F1-36 detection time
3.2 Fault Information Query and Reset
Fault History Query:
F9-14 to F9-16: Record the types of the last three faults.
F9-17 to F9-46: Record the operating status parameters at the time of the fault.
Fault Reset Methods:
Panel reset: Press the STOP/RES key.
Terminal reset: Set the DI terminal to 9.
Communication reset: Send a reset command through Modbus communication.
3.3 Fault Protection Action Settings
Fault Action Selection 1 (F9-47):
Units digit: Motor overload action.
Tens digit: Input phase loss action.
Fault Action Selection 2 (F9-48):
Units digit: Encoder fault action.
Tens digit: Parameter read/write abnormal action.
Fault Action Selection 3 (F9-49):
Units digit: Custom fault 1 action.
Tens digit: Custom fault 2 action.
IV. Advanced Functions and Application Examples
4.1 Multi-Motor Control Function
Motor Parameter Group Selection:
Select the current motor parameter group using F0-24.
Motor Parameter Settings:
First group: F1 group (motor parameters), F2 group (vector parameters).
Second group: A2 group (motor parameters), A5 group (vector parameters).
Switching Notes:
Switching must be performed in the stop state.
After switching, check the motor rotation direction.
4.2 PID Control Function Application
Basic Parameter Settings:
FA-00: PID setpoint source selection.
FA-02: PID feedback source selection.
PID Parameter Settings:
FA-05: Proportional gain Kp1.
FA-06: Integral time Ti1.
FA-07: Differential time Td1.
4.3 Communication Function Configuration
Basic Parameter Settings:
Fd-00: Baud rate setting.
Fd-01: Data format.
Fd-02: Local address.
Communication Control:
Run command: Communication address 0x1001.
Frequency setpoint: Communication address 0x1000.
V. Maintenance and Upkeep
5.1 Daily Maintenance Points
Regular Inspection Items:
Check the operation of the cooling fan.
Remove dust from the radiator.
Check the wiring terminals.
Check the electrolytic capacitors.
Maintenance Cycle Recommendations:
Daily: Check the operating status.
Monthly: Clean the radiator.
Annually: Conduct a comprehensive inspection.
5.2 Long-Term Storage Notes
Storage Environment Requirements:
Temperature: -20°C to +60°C.
Humidity: ≤95%RH (no condensation).
Inspection Before Reuse:
Measure the insulation resistance of the main circuit.
Check the control board.
5.3 Lifespan Prediction and Replacement
Lifespan Reference for Wear Parts:
Electrolytic capacitors: Approximately 8-10 years.
Cooling fans: Approximately 30,000-50,000 hours.
Replacement Notes:
Cut off the power supply and wait for 10 minutes before operation.
After replacement, check the parameter settings.
Conclusion
The XC-5000 series frequency converters are powerful and have superior performance. Through this guide, users can comprehensively master core skills such as operation panel usage, parameter settings, external control, and fault diagnosis. Correct installation, parameter settings, and maintenance are key to ensuring the long-term stable operation of the frequency converters. It is recommended that users refer to this guide and make appropriate adjustments according to specific working conditions to fully leverage the performance advantages of the XC-5000 frequency converters.
In CNC machining center maintenance and commissioning, the calibration of the Z-axis reference point and tool change point is critical for ensuring the machine’s precision and stability. This article takes the XD-40A vertical machining center manufactured by Dalian Machine Tool Group as an example. The machine is equipped with a GSK983Ma-H CNC system, DA98D servo drive, and a Sanyo OIH 5000P/R incremental encoder. The machine adopts an umbrella-type tool magazine, where the Z-axis must accurately position at the second reference point during tool change.
During routine maintenance, the Z-axis servo motor was replaced. After replacement, the machine could start and home normally, but an abnormality appeared during tool change (M06): The Z-axis stopped about 3 mm higher than before, causing the spindle taper to fail to engage the tool holder. The operator had to manually lower the Z-axis by 3 mm to complete the tool change.
Although this deviation did not trigger any alarms, it seriously affected the reliability of automatic tool change and could lead to tool gripper misalignment, incomplete release, or even tool crashes.
II. System Structure and Signal Relationship Analysis
To solve the issue, it is essential to understand how the GSK983Ma-H system defines the Z-axis “reference point (home position).” The Z-axis homing position is determined by two signals:
Proximity switch signal (HOME/ORG) – used for coarse positioning;
Encoder Z-phase signal (Z-phase) – used for fine positioning.
When the machine executes the “Home” (G28 Z0) command after power-up, the sequence is as follows:
The Z-axis moves in the specified direction until it detects the proximity switch signal.
The system records the pulse position at this point.
After the proximity signal is released, the axis continues moving.
When the next Z-phase pulse is detected, the system defines that position as the machine reference point (zero point).
Based on parameter 0161, the system then calculates the second reference point (e.g., tool change point).
Thus, the Z-axis zero position is not determined by the limit switch alone, but by the phase relationship between the proximity signal and the encoder Z-phase pulse.
III. Root Cause Analysis After Motor Replacement
In this case, the proximity switch, lead screw, and limit mechanism remained unchanged, yet a 3 mm tool change deviation occurred after replacing the motor. The underlying causes are as follows:
1. Encoder Z-phase Signal Phase Difference
Even among identical motor models, the internal encoder Z-phase position relative to the rotor magnetic pole can vary slightly due to manufacturing tolerances. When the system executes “find proximity then find Z-phase,” a phase delay or advance changes the zero-point position.
For a 5000-line encoder: [ 5\text{ mm / rev} \Rightarrow 1 \text{ Z pulse = 5 mm} ] If the Z-phase triggers 0.6 turns later, the system’s reference point shifts upward by approximately 3 mm.
2. Coupling Installation Angle Deviation
If the motor–lead screw coupling is reassembled with a slight angular misalignment or reversed orientation, the timing between the proximity and Z-phase signals changes, causing a fixed offset.
3. Second Reference Point Parameter Not Recalibrated
Parameter 0161 in the GSK system defines the distance between the first and second reference points. If the old value is retained after encoder replacement, the stored Z-phase relationship becomes invalid, resulting in a tool change height deviation.
4. Servo Phase Angle or Polarity Mismatch
If the servo drive’s electrical phase offset (in DA98D) is not re-calibrated, it can cause inconsistent homing. However, such errors typically lead to random deviations, not a consistent 3 mm offset.
IV. Parameter Framework and Signal Interaction
The GSK983Ma-H system controls Z-axis referencing using several key parameters:
Parameter
Description
Function
0160
Home direction
Defines positive or negative direction of homing
0161
Distance from 1st to 2nd reference point
Defines tool change position
0162
Home offset
Compensates fine homing deviation (if available)
0163–0165
Homing speeds
Control homing speed at each stage
0171–0175
Home switch logic
Defines trigger mode and direction
Thus, the final tool change position can be expressed as: [ Z_{tool} = Z_{prox} + ΔZ_{Z-phase} + P_{0161} ] Any change in the above components—especially the Z-phase offset—will cause a physical shift in the tool change height.
V. Comparative Analysis of Available Solutions
When parameter modification (0161) is restricted by password protection, alternative methods must be considered. Below is a comparison of practical options used in the field.
Method
Principle
Application
Advantage
Risk
Modify 0161
Adjusts tool change offset
If password available
Accurate and safe
Requires password
Adjust proximity switch
Shifts home reference mechanically
No password
Simple and direct
Changes all Z references
Change servo electronic gear ratio
Alters pulses per unit
Mismatch in lead screw
Fixes scaling
Affects entire travel accuracy
Modify home offset (if available)
Software correction
Some versions only
No mechanical adjustment
Usually locked
Adjust motor phase
Alters encoder–rotor relationship
Encoder misalignment
Permanent correction
Complex, risky
Conclusion:
If password access is available, adjusting 0161 is best.
If not, physically adjusting the proximity switch by 3 mm is the most practical.
Avoid changing gear ratios unless lead screw or encoder specifications differ.
VI. Practical Solution Without Password Access
When the system password is unknown or locked, the following mechanical method effectively corrects the deviation.
1. Required Tools
Hex wrench, caliper or feeler gauge, insulation gloves, and a tool holder or alignment gauge.
2. Determine Adjustment Direction
If Z-axis stops too high → move the proximity switch upward.
If Z-axis stops too low → move the switch downward.
3. Adjustment Procedure
Power off the machine.
Loosen the Z-axis home switch screws.
Move the switch up by approximately 3 mm.
Tighten screws and power on.
Re-home the Z-axis and test tool change.
4. Verification
Execute:
G28 Z0
M06 T1
Check if the spindle taper aligns with the tool gripper. Fine-tune the switch by ±0.5 mm if needed.
5. Update Work Coordinate
Since the machine reference has shifted, redefine the Z=0 in G54 by touching off the workpiece again.
VII. DA98D Drive Parameter Verification
To ensure that the deviation is not caused by drive scaling, verify the following parameters in the DA98D servo drive:
Parameter
Function
Recommended
Description
P1.05
Electronic gear numerator
20000
Encoder output per rev
P1.06
Electronic gear denominator
1
1:1 transmission
P2.04
Home polarity
Depends on axis
Match direction
P4.01
Auto phase calibration
Execute after motor replacement
Syncs magnetic poles
Any incorrect electronic gear ratio can cause axis scaling errors and must be restored to 1:1.
VIII. Pulse Calculation for 3 mm Offset
Given:
Lead screw pitch = 5 mm
Encoder = 5000 PPR
Pulses per revolution = 5000 × 4 = 20000
Pulses per mm = 20000 ÷ 5 = 4000
Then: [ 3 \text{ mm} × 4000 = 12000 \text{ pulses} ] To compensate for a 3 mm height difference, parameter 0161 should change by ±12000 pulses. For example:
0161: -133500 → -145500
IX. Unlocking System Parameters
If full software correction is preferred, parameter protection can be disabled as follows:
Navigate to: SYSTEM → PARAM → NC PARAM
Press SET;
When prompted, enter one of the following passwords:
Password
Description
983
GSK default
889
Service engineer code
1111 / 0000
User level
1314 / 8888
OEM-defined
After successful entry, “Protection Released” appears at the bottom of the screen, allowing parameter editing.
If unavailable, restart and hold DELETE or ALT+M during boot to enter the maintenance menu and disable “Parameter Protection.”
X. Understanding the Z-Axis Homing Logic
The following illustrates the Z-axis homing process:
From that zero, parameter 0161 defines the tool change position.
If the Z-phase occurs later relative to the proximity switch, the zero point shifts upward, making the spindle stop higher during tool change. By moving the proximity switch 3 mm upward, the zero point effectively moves downward by 3 mm, correcting the deviation.
XI. Key Lessons and Maintenance Practices
Always re-calibrate reference points after replacing incremental encoders. Even a small Z-phase shift can cause millimeter-level errors.
Back up all NC parameters before maintenance. Parameter loss or mismatch is a frequent cause of deviation.
Prefer software compensation over mechanical adjustments. Mechanical adjustments are practical but less precise.
Do not change electronic gear ratios arbitrarily. They affect all axis scaling, not just tool change height.
Umbrella-type tool changers rely heavily on parameter 0161. Incorrect values lead to failed or dangerous tool changes.
After adjustment, verify through a full test:
Home the Z-axis;
Execute tool change;
Check gripper alignment;
Recalibrate work coordinate (G54).
XII. Conclusion
This study analyzed a real case of Z-axis tool change deviation on an XD-40A vertical machining center equipped with GSK983Ma-H control and DA98D servo drives. Through a detailed investigation of encoder Z-phase behavior, servo drive settings, and CNC reference logic, it was concluded that the 3 mm deviation was caused by a Z-phase timing difference, not mechanical misalignment.
When parameter modification is possible, adjusting parameter 0161 is the optimal solution. When access is restricted, mechanically adjusting the proximity switch by 3 mm effectively compensates for the offset. If hardware specifications differ, recalibration of the electronic gear ratio is necessary.
This case highlights that CNC positioning precision depends not only on mechanical accuracy but also on the synchronization between hardware signals and software logic. A deep understanding of the system’s internal mechanisms allows technicians to restore functionality efficiently, accurately, and safely.
Preamble: Getting to Know the Weite TW-ZX Series Frequency Inverter
The Weite TW-ZX series frequency inverter is a high-performance drive control device specifically designed for lifting equipment. It is particularly suitable for precise control of heavy-duty machinery such as construction elevators and tower cranes. As a leading electrical transmission solution in the industry, this series of frequency inverters integrates advanced motor control algorithms and a rich set of functional configurations, enabling it to meet the stringent requirements of various lifting application scenarios.
This technical guide will comprehensively analyze the functional features, installation specifications, parameter settings, and maintenance essentials of the Weite TW-ZX frequency inverter, aiming to provide users with a systematic operational reference. By thoroughly understanding the content of this manual, users can fully leverage the performance advantages of the equipment, ensuring the safe, stable, and efficient operation of lifting equipment.
The TW-ZX series frequency inverter adopts optimized control algorithms specifically tailored for lifting applications, featuring core characteristics such as low-frequency high-torque output, intelligent braking control, and wide voltage adaptability. It is renowned in the industry for its high reliability and exceptional control precision. Below, we will commence with an overview of the product’s features and gradually unfold a complete application guide for this professional device.
I. Core Product Features and Technical Advantages
1.1 Professional Lifting Control Functions
The Weite TW-ZX frequency inverter is specifically designed for the lifting industry, incorporating a range of highly targeted professional functions:
Low-Frequency High-Torque Output: At 0.5Hz, it can provide 150% of the rated torque, ensuring stability during heavy-load startups and low-speed operations. This feature is particularly suitable for tower crane hoisting and elevator applications, addressing the industry challenge of insufficient torque in traditional frequency inverters at low frequencies.
Intelligent Brake Control Logic: It incorporates optimized braking timing control to precisely coordinate the actions of mechanical brakes and motors. Parameters Fb-00 to Fb-11 allow for flexible adjustment of brake release/closure frequencies and delay times, effectively preventing hook slippage and significantly enhancing operational safety.
Dynamic Current Limiting Technology: Advanced current control algorithms automatically adjust output during severe load fluctuations, preventing frequent overcurrent trips. Users can configure current stall protection characteristics via parameter FC-07 to balance system response speed and stability.
Wide Voltage Adaptability: The input voltage range extends up to 380V±20%, with automatic voltage regulation (AVR) functionality. It maintains sufficient torque output even when grid voltage drops, making it particularly suitable for construction sites with unstable grid conditions.
1.2 Hardware Design Characteristics
The TW-ZX series reflects the unique needs of lifting equipment in its hardware architecture:
Enhanced Cooling Design: The entire series adopts a forced air cooling structure with real-time protection against overheating of the散热器 (radiator) (OH fault), ensuring reliable operation in high-temperature environments. Larger power models (above 90kW) utilize an up-draft and down-draft air duct design to optimize cooling efficiency.
Modular Power Units: The power modules employ industrial-grade IGBT devices with an overload capacity of 150% rated current for 1 minute and 180% rated current for 10 seconds, fully meeting the short-term overload requirements of lifting equipment.
Rich Interface Configuration: It provides 7 multifunctional digital input terminals (X1-X7), 2 analog inputs (VS/VF for voltage signals, IS/IF for current signals), 2 open-collector outputs (Y1/Y2), and 1 relay output (R1), catering to complex control needs.
Built-in Brake Units (Select Models): Models below 18.5kW come standard with built-in brake units, allowing direct connection to brake resistors. Larger power models require external dedicated brake units, with the BR100 series recommended as a complementary product.
1.3 Control Performance Advantages
Compared to general-purpose frequency inverters, the TW-ZX series has undergone in-depth optimization in its control algorithms:
Optimized S-Curve Acceleration/Deceleration: Parameter FC-00 enables the S-curve acceleration/deceleration mode, with FC-01/02 setting the S-curve proportions for the acceleration and deceleration phases, respectively, effectively reducing mechanical shock and enhancing operational smoothness.
Multi-Speed Precise Control: It supports up to 16 preset speed stages (F3-00 to F3-14), allowing rapid switching through terminal combinations to meet the speed requirements of lifting equipment under various operating conditions. Each speed stage can independently set acceleration and deceleration times (F3-15 to F3-20).
Motor Parameter Self-Learning: It offers both stationary and rotational self-identification modes (F1-15) to automatically measure motor electrical parameters, significantly improving vector control accuracy. For applications where the load cannot be decoupled, the stationary identification mode provides a safe and reliable option.
Table: Typical Models and Specifications of the TW-ZX Series Frequency Inverter
Model
Rated Power (kW)
Rated Current (A)
Brake Unit
Dimensions (mm)
TW-ZX-011-3
11
26
Built-in
270×200×470
TW-ZX-022-3
22
48
Built-in
386×300×753
TW-ZX-045-3
45
90
Built-in
497×397×1107
TW-ZX-110-3
110
220
External
855×825×793
II. Equipment Installation and Electrical Wiring Specifications
2.1 Mechanical Installation Requirements
Proper installation is fundamental to ensuring the long-term reliable operation of the frequency inverter. The TW-ZX series requires particular attention to the following points during installation:
Installation Orientation: It must be installed vertically to ensure unobstructed airflow through the cooling ducts. Sufficient space (recommended ≥100mm) should be left on all sides to prevent heat accumulation. When multiple frequency inverters are installed side by side in a control cabinet, the ambient temperature should not exceed 40℃.
Environmental Conditions: The operating environment should have a temperature range of -10℃ to +40℃ and a humidity range of 20% to 90%RH (non-condensing). It should be avoided in locations with conductive dust, corrosive gases, or oil mist, and kept away from vibration sources and electromagnetic interference sources.
Vibration Protection: The installation base should be sturdy and vibration-free, with a maximum allowable vibration of 0.5g. For vehicle-mounted or mobile equipment applications, shock absorbers are recommended to prevent internal components from loosening due to prolonged vibration.
Protection Level: Standard models have a protection level of IP20 and are not suitable for direct exposure to outdoor or humid environments. For special environments, customized protective enclosures or models with higher protection levels should be selected.
2.2 Main Circuit Wiring Specifications
The main circuit wiring directly affects system safety and EMC performance, and must strictly adhere to the following specifications:
Power Input Terminals (R/S/T):
A suitable circuit breaker (MCCB) must be installed, with a rated current of 1.5 to 2 times the rated value of the frequency inverter.
The power cable cross-sectional area should be selected according to Table 3-3, ensuring a voltage drop not exceeding 5V.
An AC reactor (optional) can be installed on the input side to suppress grid surges and harmonics.
Motor Output Terminals (U/V/W):
Motor cables should be shielded cables or laid through metal conduits to reduce electromagnetic radiation.
It is absolutely prohibited to install power factor correction capacitors or LC/RC filters on the output side.
When the motor wiring length exceeds 50 meters, the carrier frequency should be reduced or an output reactor should be installed.
Brake Resistor Connection:
For models with built-in brake units, connect to the PB terminals. For models with external brake units, connect to the P/N terminals.
The resistance value and power rating must be strictly selected according to Table 11-1 to prevent overload damage to the brake unit.
Brake resistor wiring must use high-temperature-resistant cables and be kept away from flammable materials.
Grounding Requirements:
The protective grounding terminal must be reliably grounded (Class III grounding, grounding resistance <10Ω).
The grounding wire cross-sectional area should be no less than half of the power cable cross-sectional area, with a minimum of 16mm².
When grounding multiple frequency inverters, avoid forming grounding loops and adopt a star grounding configuration.
2.3 Control Circuit Wiring Essentials
The control circuit serves as the bridge for interaction between the frequency inverter and external devices, and special attention should be paid to the following points during wiring:
Analog Signal Processing:
Speed reference signals (VS/VF) should use twisted-pair shielded cables, with the shield grounded at one end.
Signal lines should be separated from power lines by a distance of no less than 30cm and arranged perpendicularly when crossing.
Jumpers JP1/JP2 can select the analog output M0/M1 to operate in voltage (0-10V) or current (0-20mA) mode.
Digital Terminal Configuration:
By default, X1 is set for operation, X2 for forward/reverse rotation, and X3-X7 are programmable for functions such as multi-speed control (F2-00 to F2-06).
The PLC common terminal can be connected to either 24V or COM, supporting both NPN and PNP wiring modes.
The relay output R1 (EA-EB-EC) can directly drive contactor coils, with a contact rating of 250VAC/3A.
RS485 Communication:
Use shielded twisted-pair cables to connect the A+/A- terminals, with proper termination resistor matching.
Communication parameters are set via F1-16 to F1-19, supporting the Modbus RTU protocol.
It is recommended to set the baud rate not exceeding 19200bps and reduce the rate for long-distance communication.
Figure: Standard Wiring Diagram for the TW-ZX Frequency Inverter [Insert wiring diagrams similar to Figures 12-1 to 12-4 here, showcasing typical application wiring for elevators, tower crane hoisting, etc.]
III. Parameter Settings and Functional Configuration
3.1 Basic Parameter Setting Procedure
After powering on the TW-ZX frequency inverter, follow the procedure below for basic settings:
Restore Factory Settings:
Set F0-28=1 to restore the factory settings corresponding to the application macro.
Select F4-28=9 for elevator applications and F4-28=6 for tower crane hoisting applications.
After resetting, check F0-27=1 to ensure all parameter groups are displayed.
Motor Parameter Input:
Accurately input the motor nameplate data (F1-00 to F1-07).
For elevators with dual motors in parallel, set the power and current to the sum of the two motors.
The motor winding connection method (F1-06) must match the actual configuration (Y/△).
Motor Parameter Self-Learning:
Perform rotational self-identification (F1-15=2) after decoupling the load.
If the load cannot be decoupled, select stationary self-identification (F1-15=1).
Do not operate the frequency inverter during the identification process. Parameters are automatically stored upon completion.
Speed Control Parameters:
Set the maximum frequency F0-16 (usually 50Hz) and the upper limit frequency F0-17.
Adjust the acceleration time F0-09 and deceleration time F0-10, extending them appropriately for heavy loads.
The carrier frequency F0-14 is generally set to 1-4kHz, and can be increased if noise is significant.
Terminal Function Allocation:
Configure X3-X7 according to application requirements for functions such as multi-speed control and fault reset.
Set the output functions for Y1/Y2/R1, such as fault signals and brake control.
3.2 Configuration of Lifting-Specific Functions
The TW-ZX series requires special configuration for the unique functions tailored to lifting applications:
Brake Control Timing:
Set the ascending brake release frequency Fb-00 (usually 3Hz) and the descending release frequency Fb-01.
Configure the pre-release delay Fb-02 (approximately 0.3s) and the post-release delay Fb-03.
Set the brake closure frequencies Fb-04/Fb-11 and the corresponding delays Fb-05/Fb-06.
Zero-Crossing Acceleration Function:
Enable Fb-09 to set the zero-crossing acceleration/deceleration time (approximately 2s).
Adjust Fb-10 to set the frequency point for acceleration/deceleration changes (usually 2.5Hz).
Combine with S-curve parameters FC-01/02 to achieve smooth transitions.
Brake Inspection Function:
Set the inspection torque Fd-09 (150% of rated) and time Fd-10 (4s).
Define the inspection interval Fd-16 (e.g., 80 hours).
Set the Y2 terminal to provide a brake inspection reminder (F2-13=27).
Industry-Specific Protections:
Disable current limiting FC-07=0 and overvoltage stall FC-19=0010.
The operation panel of the Sourze A500/A500S frequency inverter is equipped with comprehensive control and display functions. Its interface is composed of the following elements:
Indicator Light Area:
Unit Indicator Lights (Hz/A/V/RPM/%): Display the current parameter units.
Running Status Indicator Light (RUN): Green indicates the running state.
Control Mode Indicator Light (L/D/C): Red indicates the current control mode (panel/terminal/communication).
Direction Indicator Lights (FWD/REV): Red indicates the forward/reverse running states.
Digital Display Area: A 5-digit LED display that can show the set frequency, output frequency, monitoring data, and alarm codes.
Keyboard Buttons:
PRG/ESC: Enter/exit the menu.
ENTER: Confirmation key.
+/-: Data increment/decrement.
>: Cycle through displayed parameters.
RUN: Running key.
STOP/RESET: Stop/reset key.
QUICK/JOG: Jog running/direction key.
2. Restoring Factory Parameters
Parameters can be initialized using function code A0-28:
Enter parameter A0-28 (parameter initialization operation).
Set it to 1: Restore factory parameters (excluding motor parameters, recorded information, and A0-20).
Press the ENTER key to confirm and execute.
The system will automatically return after completion.
3. Password Setting and Management
Setting a Password:
Enter A7-50 (user password).
Set it to a non-zero number (e.g., 12345).
The password protection will take effect after returning to the status interface.
After Password Protection is Activated:
Pressing the PRG key will display “—–“.
The correct password must be entered to view and modify function codes.
Incorrect entries will keep the display as “—–“.
Clearing the Password:
Enter the menu using the password.
Set A7-50 to 0.
The password protection function will be canceled.
4. Parameter Access Restriction Settings
Parameter read-only mode can be set using function code E0-00:
Enter E0-00 (function code read-only selection).
Set it to 1: All function codes except E0-00 can only be viewed but not modified, preventing accidental parameter changes.
II. External Terminal Control and Speed Adjustment Settings
1. External Terminal Forward/Reverse Control
Hardware Wiring:
Forward signal: Connect to the X(DI)2 terminal (default FWD function).
Reverse signal: Connect to the X(DI)4 terminal (default REV function).
Common terminal: COM terminal.
24V power supply: Provides power for external switches (optional).
Parameter Settings:
A0-04 = 1: Select the terminal command channel.
A5-01 = 1: Set X2(DI2) for forward running.
A5-03 = 2: Set X4(DI4) for reverse running.
A5-11 = 0: Select two-wire operation mode 1.
Control Logic:
SW1 closed: Forward running.
SW2 closed: Reverse running.
Both closed or open: Stop running.
2. External Potentiometer Speed Adjustment
Hardware Wiring:
Connect the three terminals of the potentiometer as follows:
Upper terminal: +10V.
Sliding terminal: AI1.
Lower terminal: GND.
Recommended potentiometer resistance: 1-5kΩ.
Parameter Settings:
A0-06 = 2: Select AI1 as the main frequency source.
A5-15 = 0.00V: Minimum input value for AI1.
A5-16 = 0.0%: Corresponding to 0.0%.
A5-17 = 10.00V: Maximum input value for AI1.
A5-18 = 100.0%: Corresponding to 100.0%.
Calibration Adjustment:
If the actual speed does not match the potentiometer position, adjust A5-15 to A5-18.
Different AI curve characteristics can be selected via A5-45.
III. Fault Diagnosis and Handling
1. Common Fault Codes and Solutions
Fault Code
Fault Name
Possible Causes
Solutions
Err12
Undervoltage Fault
Input power voltage too low
Check if the power voltage is within the allowable range (±20%)
Err14
Motor Overload
Excessive load or short acceleration time
Check the mechanical load and adjust the acceleration time in A0-23
Err20
Ground Short Circuit
Motor or cable insulation damage
Disconnect the inverter and check the motor insulation resistance (should be ≥5MΩ)
Err23
Input Phase Loss
Three-phase input phase loss
Check the input power wiring
Err24
Output Phase Loss
Motor or output cable fault
Check the output wiring and motor
Err27
Communication Fault
Communication interruption or format error
Check the communication line and confirm the settings in A8-00 to A8-05
Err28
External Fault
External fault terminal activation
Check the external fault signal source
Err29
Excessive Speed Deviation
Load突变 (sudden change) or inaccurate motor parameters
Retune the motor (A1-00 = 2)
2. Fault Reset Methods
Panel Reset: Use the STOP/RESET key.
Terminal Reset: Set any X(DI) terminal function to 9 (fault reset).
Automatic Reset: Set A9-11 (number of fault automatic resets) and A9-13 (reset interval time).
3. Fault Record Inquiry
Historical fault records can be viewed through the U0 group parameters:
U0-00 to U0-03: The last 4 fault codes.
U0-04 to U0-07: Corresponding running frequencies at the time of the faults.
U0-08 to U0-11: Corresponding output currents at the time of the faults.
U0-12 to U0-15: Corresponding DC bus voltages at the time of the faults.
IV. Advanced Function Applications
1. Multi-Speed Control
Setting Steps:
A0-06 = 4: Select multi-speed as the frequency source.
Set AC-00 to AC-15: Define 16 speed frequency values.
Allocate X(DI) functions: Set A5-00 to A5-04 to 12 to 15 (multi-speed terminals 1 to 4).
Combination Control:
Through 4 DI terminals, 16 states can be combined (binary 0000 to 1111).
Each state corresponds to one of the frequency values in AC-00 to AC-15.
2. PID Control Application
Basic Settings:
A0-06 = 6: Select PID as the frequency source.
AA-00: Select the PID setpoint source (e.g., AI1).
AA-03: Select the PID feedback source (e.g., AI2).
AA-04: Set the PID action direction (0 for positive, 1 for negative).
Parameter Adjustment:
AA-06: Proportional gain (increase to speed up response).
AA-07: Integral time (decrease to eliminate steady-state error).
AA-08: Derivative time (improve dynamic characteristics).
3. Frequency Sweep Function
Suitable for the textile and chemical fiber industries:
Ab-00 = 0: Sweep amplitude relative to the center frequency.
Ab-01 = 30.0%: Set the sweep amplitude.
Ab-03 = 10.0s: Set the sweep frequency period.
Ab-04 = 50.0%: Triangular wave rise time coefficient.
V. Maintenance and Upkeep
1. Daily Inspection Items
Check for abnormal motor running sounds.
Check motor vibration.
Check the operation status of the inverter’s cooling fan.
Check for overheating of the inverter.
2. Regular Maintenance
Clean the air duct dust every 3 months.
Check the tightness of screws.
Check the wiring terminals for arc traces.
Use a 500V megohmmeter to test the main circuit insulation (disconnect the inverter).
3. Replacement Cycles for Wear Parts
Cooling fan: 2-3 years (depending on the usage environment).
Electrolytic capacitor: 4-5 years.
4. Long-Term Storage Precautions
Store in the original packaging.
Power on every 2 years (for at least 5 hours).
The input voltage should be raised slowly to the rated value.
Conclusion
The Sourze A500 series frequency inverter is powerful and flexible, capable of meeting various industrial application requirements through reasonable settings. This guide provides a detailed introduction to the entire process, from basic operations to advanced applications. It is recommended that users carefully read the relevant sections of the manual before use, especially the safety precautions. For complex application scenarios, it is advisable to contact the manufacturer’s technical support for professional guidance.
Operation Panel Functions and Parameter Settings 1.1 Operation Panel Features
The YTA/YTB series features a 4-digit LED display panel with:
Status indicators: RUN (operation), STOP (stop), CTC (timer/counter), REV (reverse) Function keys: FUNC: Parameter setting PROC: Parameter save ▲/▼: Frequency adjustment FWD/REV: Forward/reverse control STOP/RESET: Stop/reset 1.2 Password Protection and Parameter Initialization
Password Setup:
Press FUNC to enter parameter mode Set D001 parameter (user password) to 1 for unlocking Restore to 0 after modification to lock parameters
Factory Reset:
Unlock parameters (D001=1) Locate D176 parameter (factory reset) Set to 1 and press PROC to execute initialization
External Control Implementation 2.1 External Terminal Forward/Reverse Control
Wiring:
Forward: Connect FWD terminal to COM Reverse: Connect REV terminal to COM Common: COM terminal
Parameter Settings:
D032=1 (external terminal control) D096=0 (FWD for forward/stop, REV for reverse/stop) D036=2 (allow bidirectional operation) D097 sets direction change delay (default 0.5s) 2.2 External Potentiometer Speed Control
Wiring:
Potentiometer connections: Ends to +10V and COM Wiper to AVI terminal AVI range selection via DIP switch (0-5V or 0-10V)
Parameter Configuration:
D031=1 (frequency source from AVI) Match potentiometer output range with DIP switch Set D091-D095 for analog-frequency mapping
Fault Diagnosis and Solutions 3.1 Common Error Codes Code Meaning Solution Eo/EoCA Overcurrent Increase acceleration time (D011) EoCn Running overcurrent Check load/motor condition EoU Overvoltage Extend deceleration time (D012) EoL Overload Reduce load or increase capacity ELU Undervoltage Check power supply voltage 3.2 Maintenance Guidelines
Regular Checks:
Clean heat sinks and vents every 3 months Verify terminal tightness Monitor operating current Record fault history (D170-D172)
Advanced Functions 4.1 PLC Programmable Operation
Configuration:
D120=1/2/3 (select single/cyclic/controlled cycle) D122-D136 set segment speeds D141-D156 set segment durations D137/D138 set direction for segments 4.2 PID Closed-loop Control
Setup:
D070=1 (enable PID) D072-D074 set P/I/D parameters Connect feedback signal to ACI terminal (4-20mA) Set target value via AVI or panel 4.3 RS485 Communication
Parameters:
D160: Station address (1-254) D161: Baud rate (4800-38400bps) D163: Communication format (8N2 RTU mode)
This guide covers all operational aspects from basic controls to advanced applications of Yuchao YTA/YTB series inverters. For complex issues, please contact us.
