When people talk about “programming” a Variable Frequency Drive (VFD), they are not usually referring to traditional software programming such as C++, Python, or Java.
In most industrial applications, VFD programming means configuring parameters and control functions that determine how the drive operates the motor, responds to external signals, and communicates with PLCs or other automation systems.
For engineers, electricians, and commissioning technicians, understanding this distinction is important. You normally do not need to write a large amount of code to configure a VFD. Instead, you need to understand the motor, control commands, reference sources, input and output signals, protection functions, and communication settings.
This article explains a practical three-level approach to programming and commissioning a WOLONG VFD.
A VFD controls an AC motor by adjusting the output voltage, frequency, and other control variables according to the configured operating mode.
To make the drive operate correctly, technicians normally configure parameters for:
Motor nameplate data
Start and stop commands
Speed or frequency reference
Forward and reverse operation
Acceleration and deceleration
Digital inputs and outputs
Analog inputs and outputs
Protection functions
PID control
Communication
Application-specific functions
The exact parameter numbers and menu structure depend on the VFD series.
For WOLONG VFDs, parameter configuration should always follow the relevant product manual and application requirements.
The basic commissioning logic, however, is straightforward.
The first level is about getting the VFD and motor operating safely.
Before configuring advanced functions, make sure the basic motor and drive configuration is correct.
Before applying power, verify the complete installation.
Check that:
The VFD rating is suitable for the motor and application.
The input power matches the VFD requirements.
The motor cable is correctly connected.
Protective grounding is properly installed.
The motor is connected to the VFD output terminals correctly.
Control wiring is correctly identified.
The installation environment meets the VFD's temperature, humidity, ventilation, and protection requirements.
In a typical three-phase VFD installation, the incoming AC power is connected to the drive input terminals, while the motor is connected to the drive output terminals.
Never connect the incoming AC supply directly to the VFD output terminals.
Always follow the wiring diagram for the specific WOLONG VFD model.
Before entering parameters, record the information shown on the motor nameplate.
Typical motor data includes:
Rated power
Rated voltage
Rated current
Rated frequency
Rated speed
Number of poles
Power factor
Motor connection
For example, a motor may be rated:
90 kW / 400 V / 50 Hz / 1480 rpm
The actual values must be taken from the motor nameplate.
Entering accurate motor data is one of the most important steps in VFD commissioning.
Incorrect motor parameters can result in:
Poor speed control
Excessive motor current
Insufficient torque
Motor overheating
Incorrect protection behavior
Poor vector-control performance
Many modern VFDs support a motor identification or auto-tuning function.
Depending on the drive and selected control mode, the VFD can perform electrical measurements to obtain additional motor characteristics and optimize its control model.
This can significantly improve motor performance, particularly when using vector control.
There are generally two types of identification procedures:
Static identification:
The motor remains stationary while the drive performs electrical measurements.
Rotating identification:
The motor rotates during the identification process.
The available functions depend on the VFD model.
Before performing motor identification, make sure the mechanical system is safe.
For rotating identification, ensure that:
The motor can rotate freely.
The machine is in a safe condition.
Personnel are clear of moving equipment.
Unexpected rotation will not damage the machine or process.
Never perform a rotating motor identification procedure without first checking the mechanical system and the manufacturer's instructions.
After configuring the motor, determine how the VFD will receive its start and stop commands.
This is called the run command source or command source.
Common options include:
The operator starts and stops the motor using the VFD keypad or control panel.
This is useful for:
Commissioning
Testing
Maintenance
Standalone equipment
External switches, push buttons, relays, or PLC outputs are connected to the VFD digital inputs.
For example:
DI1 → Run/Stop
DI2 → Forward/Reverse
DI3 → Fault Reset
The exact terminal assignment can be configured according to the application.
A PLC, HMI, SCADA system, or other controller sends run commands through an industrial communication network.
This approach is common in automated production systems.
The next question is:
How does the VFD know how fast the motor should run?
This is determined by the speed reference or frequency reference source.
Typical options include:
The operator enters the required frequency or speed directly from the keypad.
For example:
25 Hz → low-speed operation
50 Hz → rated-frequency operation
The speed reference comes from an analog input.
Common industrial signals include:
0–10 V
4–20 mA
For example, a potentiometer can provide a variable voltage reference, while a pressure or flow transmitter may provide a 4–20 mA signal.
Several digital inputs can be assigned to select predefined speed values.
For example:
Speed 1 = 20 Hz
Speed 2 = 30 Hz
Speed 3 = 40 Hz
Speed 4 = 50 Hz
The number of available preset speeds depends on the VFD model and control configuration.
A PLC or automation controller can send a digital speed reference through the communication network.
This is particularly useful when multiple drives must be coordinated by a central control system.
At this point, the most important control relationship is:
Run Command + Speed Reference = Basic Motor Control
The run command tells the VFD:
“Should the motor run?”
The speed reference tells it:
“At what speed should it operate?”
For example:
Run command: Digital input
Speed reference: 0–10 V analog input
This means an external switch can start the motor while a potentiometer determines its operating speed.
This simple configuration is widely used in industrial machinery.
Once the basic motor control has been established, the VFD can be configured for more advanced applications.
This is where VFD programming becomes more than simply starting and stopping a motor.
A VFD can be configured with multiple preset speeds.
Digital inputs can be assigned as speed-selection inputs.
For example:
DI1 = Run
DI2 = Speed Selection 1
DI3 = Speed Selection 2
Different combinations of the digital inputs can select different preset speeds.
This can be useful for:
Conveyors
Machine tools
Material handling equipment
Packaging machines
Processing equipment
Many WOLONG VFD applications can use PID control for automatic process regulation.
A common example is a constant-pressure water supply system.
The basic control loop is:
Pressure Setpoint → PID Controller → VFD → Pump → Pressure Sensor → Feedback
The pressure sensor sends a feedback signal to the VFD.
The VFD compares the actual pressure with the desired pressure and adjusts the motor speed accordingly.
For example:
If pressure is too low:
VFD increases pump speed
If pressure is too high:
VFD reduces pump speed
Typical PID configuration includes:
PID enable
Setpoint source
Feedback source
Feedback scaling
Proportional gain
Integral time
Derivative function, when required
Output limits
Sleep/wake functions, where applicable
PID parameters should be tuned according to the actual process dynamics rather than simply using default values.
Industrial equipment often needs both local and remote operating modes.
For example:
Local mode → operator controls the VFD from the local interface
Remote mode → PLC controls the VFD
A digital input or selector switch can be assigned to switch between these operating modes, depending on the system design.
This is particularly useful during:
Commissioning
Maintenance
Troubleshooting
Automatic production
A well-designed local/remote control strategy allows technicians to test equipment locally while maintaining normal automatic operation when the system is returned to service.
The third level involves integrating the VFD into a complete automation system.
At this level, programming is normally performed in the PLC, DCS, SCADA system, or industrial controller rather than inside the VFD itself.
The VFD becomes one controlled device within the larger automation architecture.
Depending on the VFD and communication option, the system may use protocols such as:
Modbus RTU
Modbus TCP
PROFINET
EtherNet/IP
CANopen
Other industrial communication protocols
The PLC and VFD must be configured with compatible communication parameters.
Depending on the network, this may include:
Device address
IP address
Baud rate
Node ID
Communication format
Data mapping
Network configuration
When a VFD is controlled through a fieldbus, the PLC does not simply send a text command such as “START MOTOR.”
Instead, data is normally exchanged using defined words, registers, bits, or structured data.
For example, the PLC may send:
Control word
Speed reference
while the VFD returns:
Status word
Actual speed
Output current
Fault information
Drive status
The exact data structure depends on the communication protocol and VFD.
Understanding the communication data structure is essential when integrating WOLONG VFDs into a PLC-controlled system.
Once communication is established, the PLC program can control the VFD.
A typical control sequence might look like:
Start command → Enable drive → Set speed reference → Monitor drive status → Monitor actual speed → Detect faults
The PLC can also implement application-specific logic.
For example:
If a pump pressure is too low:
Increase speed reference
If pressure reaches the setpoint:
Maintain speed
If a drive fault occurs:
Stop the process and generate an alarm
For complex systems, the PLC may also coordinate multiple VFDs, valves, sensors, pumps, fans, and other equipment.
Many modern VFDs provide predefined application configurations, often referred to as:
Application macros
Connection macros
Quick setup
Application presets
Commissioning assistants
These functions provide predefined parameter configurations for common applications.
For example, an application configuration may assign:
Digital input → Run/Stop
Analog input → Speed reference
Digital input → Fault reset
Instead of manually configuring every parameter, the technician can start with an appropriate application configuration and then adjust the remaining parameters.
This can significantly reduce commissioning time.
The exact functions and terminology depend on the WOLONG VFD series.
For larger installations, PC-based commissioning software can make VFD configuration considerably easier.
Depending on the WOLONG VFD platform and available software tools, engineers may use PC tools to:
Configure parameters
Monitor operating values
View fault history
Perform commissioning
Back up parameters
Restore parameters
Compare parameter sets
Monitor trends and operating conditions
Graphical software is particularly useful when commissioning multiple drives or troubleshooting intermittent problems.
Once a VFD has been successfully commissioned, the parameter configuration should be backed up.
This is one of the simplest ways to reduce future maintenance time.
A parameter backup can be stored on:
A commissioning computer
An approved memory device
A service workstation
A controlled company server
For multiple machines using the same drive configuration, an approved parameter set can be used as a starting point for other drives.
However, technicians should never assume that identical machines have identical parameter requirements.
Before loading a parameter set into another VFD, always verify:
Motor nameplate data
Drive rating
Application requirements
I/O configuration
Communication settings
Safety-related settings
Parameter cloning should be controlled and documented.
VFD commissioning does not end when the motor starts.
A properly configured drive should also be monitored under normal operating conditions.
Important operating values include:
Output frequency
Output current
DC-link voltage
Motor speed
Torque
Temperature
Fault history
Communication status
If the drive trips, do not simply reset the fault repeatedly.
First determine the cause.
Common VFD faults include:
Overcurrent
Overvoltage
Undervoltage
Overtemperature
Motor overload
Communication failure
Ground fault
External fault
The fault code should be interpreted together with the machine condition and drive parameters.
For most applications, a structured commissioning sequence is more effective than changing parameters randomly.
A practical workflow is:
1. Check the hardware
↓
2. Verify motor nameplate data
↓
3. Enter motor parameters
↓
4. Select the motor control mode
↓
5. Perform motor identification when required
↓
6. Select the run command source
↓
7. Select the speed reference source
↓
8. Configure acceleration and deceleration
↓
9. Check motor direction
↓
10. Perform a low-speed test
↓
11. Test the complete operating range
↓
12. Configure application-specific functions
↓
13. Configure PLC or fieldbus communication if required
↓
14. Test protection and fault handling
↓
15. Back up the final parameter configuration
This sequence provides a systematic approach to commissioning and troubleshooting.
You do not need to memorize hundreds of parameters to become effective at VFD commissioning.
Instead, focus on the underlying control architecture.
Ask these questions:
What motor am I controlling?
What is the motor's rated voltage, current, frequency, and speed?
Where does the run command come from?
Where does the speed reference come from?
What do the digital inputs do?
What do the analog inputs represent?
Is the VFD operating in V/Hz or vector control?
Does the application require PID, multi-speed, or other advanced functions?
Does the VFD need to communicate with a PLC?
How will faults and parameter backups be handled?
Once these questions are answered, the actual parameter configuration becomes much easier.
WOLONG provides variable frequency drive solutions for a wide range of industrial motor applications.
Depending on the application, VFD systems can be configured for:
General-purpose motor control
Pumps and fans
Conveyors
Compressors
Process machinery
Water and wastewater systems
Mining and metallurgy
Cement production
Power generation
Petrochemical applications
OEM machinery
WOLONG VFD solutions can support different control architectures, from simple keypad operation and terminal control to analog speed references, PID regulation, and PLC-based industrial communication.
The right configuration depends on the motor, machine, process, and required control system.
If you need help selecting or configuring a WOLONG VFD for your application, contact our technical team:
“Programming” a VFD is usually less about writing traditional software and more about understanding and configuring the drive's control architecture.
The process can be viewed in three levels:
Level 1: Basic commissioning
Configure the motor, run command, speed reference, and basic operating parameters.
Level 2: Advanced drive functions
Configure multi-speed operation, PID control, local/remote control, and application-specific functions.
Level 3: System integration
Connect the VFD to a PLC, DCS, SCADA system, or industrial network and exchange control, status, and process data.
Once these three levels are understood, VFD commissioning becomes a structured engineering process rather than a matter of memorizing parameter numbers.
The parameter names may change from one drive series to another, but the underlying logic remains the same: configure the motor, define the command source, define the speed reference, configure the required functions, integrate the drive with the control system, and verify the final operation.
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