石墨岛搬移上位机系统设计与实现：基于 Modbus TCP 的状态机与安全联锁

public enum BoatState { Idle, Homing, Ready, Picking, Moving, Placing, Error }

public interface IPlcClient
{
    Task<bool> ReadCoilAsync(ushort addr);
    Task WriteCoilAsync(ushort addr, bool value);
    Task WriteRegisterAsync(ushort addr, ushort value);
    Task<bool> ReadInputAsync(ushort addr);
}

public class BoatMoveController
{
    private readonly IPlcClient _plc;
    private BoatState _state = BoatState.Idle;

    public BoatMoveController(IPlcClient plc) => _plc = plc;

    public async Task LoopAsync(CancellationToken ct)
    {
        while (!ct.IsCancellationRequested)
        {
            if (!await SafetyOkAsync())
            {
                _state = BoatState.Error;
                await _plc.WriteCoilAsync(99, false);
                await Task.Delay(500, ct);
                continue;
            }

            switch (_state)
            {
                case BoatState.Idle:
                    if (await _plc.ReadCoilAsync(0)) _state = BoatState.Homing;
                    break;
                case BoatState.Homing:
                    await _plc.WriteCoilAsync(10, true);
                    if (await _plc.ReadCoilAsync(11)) _state = BoatState.Ready;
                    break;
                case BoatState.Ready:
                    if (await _plc.ReadCoilAsync(1)) _state = BoatState.Picking;
                    break;
                case BoatState.Picking:
                    await _plc.WriteCoilAsync(20, true);
                    if (await _plc.ReadCoilAsync(21)) _state = BoatState.Moving;
                    break;
                case BoatState.Moving:
                    await _plc.WriteRegisterAsync(30, 1000);
                    if (await _plc.ReadCoilAsync(31)) _state = BoatState.Placing;
                    break;
                case BoatState.Placing:
                    await _plc.WriteCoilAsync(40, true);
                    if (await _plc.ReadCoilAsync(41)) _state = BoatState.Idle;
                    break;
                case BoatState.Error:
                    await Task.Delay(1000, ct);
                    break;
            }
            await Task.Delay(50, ct);
        }
    }

    private async Task<bool> SafetyOkAsync()
    {
        return await _plc.ReadInputAsync(0)   // 急停
            && await _plc.ReadInputAsync(1)   // 安全光栅
            && await _plc.ReadInputAsync(2);  // 限位
    }
}