WHB04B-6 CNC Pendant Controller

A .NET 8 library and console application for interfacing with the WHB04B-6 wireless CNC pendant remote controller via USB. Provides a strongly typed high level API using direct HID communication (no longer requires vendor PHB04B.dll).

Application

flowchart LR
    CNC[CNC System]
    Pendant[WHB04B Pendant]
    
    subgraph WHB04BClient
        HID[HID Communication]
    end

    CNC <--> HID
    HID <--> Pendant

Loading

Features

• Direct HID Communication: Native USB HID communication with WHB04B-6 pendant (no vendor DLL required)
• Real-time Input Processing: Continuously polls pendant for button presses, dial positions, and jog wheel movements
• Display Output: Send coordinate data and control information to the pendant's LCD display
• Modern C# Implementation: Built with .NET 8, using latest C# features and best practices
• Exception Handling: Comprehensive error handling with specific exception types for pendant operations

Hardware Requirements

• WHB04B-6 wireless CNC pendant
• USB receiver/controller for the pendant
• Cross-platform compatible (Windows, Linux, macOS)

Project Structure

• WHB04BClient.csproj - Project file for .NET 8 application
• HidCommunication.cs - Direct HID communication implementation using HidSharp library
• WHB04BClient.cs - High-level managed client with automatic polling and event handling
• PendantInputData.cs - Classes for parsing pendant input (buttons, dials, jog wheel)
• PendantDisplayData.cs - Classes for formatting display output data
• HidCommunicationException.cs - Custom exception types for HID communication operations
• Program.cs - Console application demonstrating library usage

Usage

Basic Example

using var controller = new WHB04BClient();

// Subscribe to input events
controller.DataChanged += (sender, e) =>
{
    Console.WriteLine($"[{e.Timestamp:HH:mm:ss.fff}] " +
                     $"Key1: {e.FirstKeyPressed} | Key2: {e.SecondKeyPressed} | " +
                     $"RightDial: {e.RightDial} | LeftDial: {e.LeftDial} | " +
                     $"Jog: {e.JogCountOffset}");
};

// Send display data
var displayData = new PendantDisplayData(
    JogMode.Continuous,
    CoordinateSystem.XYZ,
    number1: 123.4567m,  // X coordinate
    number2: -98.7654m,  // Y coordinate
    number3: 0.1234m,    // Z coordinate
    feedRate: 120,       // 120% feed rate (displayed as "F:120")
    spindleRate: 1200    // 1200 RPM (displayed as "S:1200")
);

controller.SendDisplayData(displayData);

Input Data

The pendant provides the following data through the PendantInputData event:

• Timestamp (DateTime) - When the data was received
• FirstKeyPressed (KeyPressed) - Primary button press (Key1 - Key16, None, Unknown)
• SecondKeyPressed (KeyPressed) - Secondary button press(Key1 - Key16, None, Unknown)
• RightDial (DialPosition) - Right rotary dial position (Position1 - Position7, Unknown)
• LeftDial (DialPosition) - Left rotary dial position (Position1 - Position7, Unknown)
• JogCountOffset (int) - Jog wheel movement offset since last poll (-128 to +127)

Display Output

Coordinate Values

Display accepts any values for X, Y and Z positions. Range: ±65535.9999

⚠️ Important: The pendant display will not update if the left dial is in Position1 (Off). Ensure the left dial is set to Position2 or higher for display data to be visible.

Jog Mode

Display accepts any one of 4 choices:

None

Continuous

Step

Reset

Coordinate System

Display accepts any one of 2 choices:

X, Y, Z / A, B, C

X1, Y1, Z1 / A1, B1, C1

Selected Axis

Always matches the chosen option in the left dial.

Primary (XYZ) / Secondary (ABC) Axis

Axis names shown always match chosen option in the left dial.

Percentage

Percentage always matches chosen option in the right dial.

Building

Requires .NET 8 SDK:

cd src
dotnet build

Running

cd src
dotnet run

The console application will:

1. Initialize the pendant controller
2. Display real-time input data from the pendant
3. Send sample coordinate data to the pendant display every 10 seconds
4. Run until Ctrl+C is pressed

Dependencies

• .NET 8.0
• HidSharp NuGet package (cross-platform HID library)

Changes Made

• ✅ Replaced PHB04B.dll dependency with direct HID communication using HidSharp
• ✅ Updated input packet parsing to handle 8-byte HID packets (vs 5-byte vendor format)
• ✅ Updated output packet generation to create 21-byte HID compatible format
• ✅ Mapped all button key codes to match LinuxCNC implementation exactly
• ✅ Cross-platform compatibility (no longer Windows-only)
• ✅ Added support for feed rate and spindle speed display (F:xxx and S:xxxx)

Acknowledgments

This implementation is based on the excellent reverse engineering work done by the LinuxCNC community for the XHC WHB04B-6 pendant. Special thanks to:

• Raoul Rubien (github.com/rubienr) - Original author of the LinuxCNC xhc-whb04b-6 component
• alkabal_free.fr - Updated the LinuxCNC component for LinuxCNC 2020
• LinuxCNC Project - For the open-source CNC control software and community
• Machinekit contributors - Listed at https://github.com/machinekit/machinekit/graphs/contributors

The USB protocol documentation, button mappings, and HID communication patterns used in this .NET implementation are derived from their reverse engineering efforts documented in the LinuxCNC xhc-whb04b-6 component.

Source code for the LinuxCNC xhc-whb04b-6 component: https://github.com/LinuxCNC/linuxcnc/tree/master/src/hal/user_comps/xhc-whb04b-6

License

See LICENSE file for details.

Note: This project is not associated or endorsed by Chengdu Xinhecheng Technology Co.,Ltd.