ZeroBus.Core 1.1.0

ZeroBus

ZeroBus is a deterministic industrial motion fieldbus engine for .NET with zero external dependencies. It provides:

1. CAN 2.0A / 2.0B & SocketCAN Core: Zero-allocation raw CAN frame transport, hardware acceptance filters, and lock-free virtual bus routers.
2. CANopen Application Layer (CiA 301): Network Management (NMT Master), Service Data Object (SDO Client with expedited & segmented transfers), and Process Data Objects (PDO).
3. CiA 402 Servo Drive & Motion Control: Multi-axis servo drive state machine transitions (Shutdown, SwitchOn, EnableOperation) with Profile Position (PPM), Profile Velocity (PVM), and Cyclic Synchronous Position (CSP).
4. EtherCAT Master Stack: Pure C# EtherCAT state machine (Init, Pre-Op, Safe-Op, Op), Datagram serialization (APRD, FPRD, BRD, LRW), CoE (CANopen over EtherCAT), and sub-millisecond cyclic PDO exchange.

🏛️ Architecture & Governance

ZeroBus complies strictly with SPEC-ARCH-001 as a Tier 2 (Transport & Storage) subsystem. It cleanly separates real-time deterministic servo motion fieldbuses (ZeroBus) from general PLC register polling (ZeroComm).

       Tier 0: ZeroPrimitives & ZeroConcurrency (Lock-Free Ring Buffers & Schedulers)
                         ↓
       Tier 2: ZeroBus (CAN / CANopen CiA 402 & EtherCAT Master)
                         ↓
       Tier 3: ZeroMotion (Kinematics & Trajectory Feedforward Coordinates)

📦 Developer API Examples

1. Multi-Axis Servo Control over CANopen (CiA 402)

using ZeroBus.Can;
using ZeroBus.CanOpen;

// 1. Initialize Virtual or SocketCAN Transport
var bus = new VirtualCanBus();
using var transport = new VirtualCanTransport(bus);
await transport.ConnectAsync();

// 2. Attach CANopen NMT Master & SDO Client
var nmt = new NmtMaster(transport);
var sdo = new SdoClient(transport);

// 3. Connect CiA 402 Servo Drive (Node ID 1)
var drive = new CiA402Drive(nodeId: 1, transport, sdo);

// 4. Power up servo state machine
await nmt.StartNodeAsync(1);
await drive.StartupServoAsync();

// 5. Send Cyclic Synchronous Position (CSP) command
await drive.SendCspPdoAsync(controlword: 0x000F, targetPosition: 125000);

2. EtherCAT Master Scan & State Transition

using ZeroBus.EtherCat;

using var ecTransport = new VirtualEtherCatTransport();
await ecTransport.ConnectAsync();

var master = new EtherCatMaster(ecTransport);

// 1. Scan online slaves via Broadcast Read (BRD)
int slaveCount = await master.ScanSlavesAsync();
Console.WriteLine($"Discovered {slaveCount} EtherCAT slaves.");

// 2. Transition slaves from Init -> Pre-Op -> Safe-Op -> Operational
await master.TransitionStateAsync(EtherCatState.PreOp);
await master.TransitionStateAsync(EtherCatState.SafeOp);
await master.TransitionStateAsync(EtherCatState.Op);

// 3. High-frequency cyclic PDO process data exchange
byte[] txPdo = new byte[32]; // Target positions / controlwords
byte[] rxPdo = new byte[32]; // Actual positions / statuswords
ushort wkc = await master.ExchangeProcessDataAsync(txPdo, rxPdo);

3. Multi-Axis Motion Coordination & Following-Error Trip

using ZeroBus.CanOpen;

// Multi-axis coordinator ensures lockstep execution and mechanical safety
var sync = new SyncProducer(transport);
var coordinator = new MotionBusCoordinator(sync);

coordinator.AddAxis(driveAxis1, maxAllowedFollowingError: 500);
coordinator.AddAxis(driveAxis2, maxAllowedFollowingError: 500);

// Emergency trip callback (triggers sub-ms QuickStop on mechanical jamming)
coordinator.OnFollowingErrorTripped += (nodeId, error, max) =>
{
    Console.WriteLine($"[EMERGENCY] Node {nodeId} tripped following error: {error} counts!");
};

// Cyclic synchronous tick (called at 250Hz - 1kHz)
await coordinator.SyncTickAsync(new int[] { targetPos1, targetPos2 });

4. CANopen Heartbeat & Liveness Monitor

var monitor = new HeartbeatMonitor(transport);
monitor.RegisterNode(nodeId: 2);

monitor.OnNodeTimeout += nodeId =>
{
    Console.WriteLine($"[ALERT] Servo Drive Node {nodeId} connection lost!");
};

// Periodically evaluate slave liveness
monitor.CheckTimeouts(TimeSpan.FromMilliseconds(200));

5. EtherCAT CoE (CANopen over EtherCAT) Mailbox Transfer

using ZeroBus.EtherCat;

// Build SDO Download (Write Target Velocity 0x60FF)
byte[] sdoWriteFrame = EtherCatCoeMailbox.BuildSdoDownload(
    index: 0x60FF, subIndex: 0,
    value: BitConverter.GetBytes(50000),
    slaveAddress: 1001
);

// Build SDO Upload (Read Actual Position 0x6064)
byte[] sdoReadFrame = EtherCatCoeMailbox.BuildSdoUpload(index: 0x6064, subIndex: 0);

📄 License

MIT License © 2026 Phong Võ. Part of the ZeroPlatform project.