新增 scene.signal 信号交互插件，落地 PLC 握手与扫车放行。

Co-authored-by: Cursor <cursoragent@cursor.com>

StandardScene.Signal/Plc/SiemensPlcSession.cs

@@ -0,0 +1,152 @@
+using System;
+using System.Text.RegularExpressions;
+using IoTClient.Clients.PLC;
+using IoTClient.Common.Enums;
+
+namespace StandardScene.Signal.Plc
+{
+    /// <summary>西门子 S7 长连接。地址兼容 Hsl 的 DB1.0 与 IoTClient 的 DB1.DBB0。</summary>
+    public sealed class SiemensPlcSession : IDisposable
+    {
+        private static readonly Regex BareDbByte = new Regex(@"^DB(\d+)\.(\d+)$", RegexOptions.IgnoreCase | RegexOptions.Compiled);
+
+        private readonly SiemensVersion _version;
+        private readonly string _ip;
+        private readonly int _port;
+        private readonly byte _slot;
+        private SiemensClient _client;
+        private readonly object _sync = new object();
+
+        public SiemensPlcSession(string version, string ip, int port, int slot)
+        {
+            _version = ParseVersion(version);
+            _ip = ip ?? "";
+            _port = port > 0 ? port : 102;
+            _slot = (byte)Math.Max(0, slot);
+        }
+
+        public bool Connected
+        {
+            get
+            {
+                lock (_sync) return _client?.Connected == true;
+            }
+        }
+
+        public bool EnsureOpen()
+        {
+            lock (_sync)
+            {
+                try
+                {
+                    if (_client == null)
+                        _client = new SiemensClient(_version, _ip, _port, _slot);
+                    if (_client.Connected)
+                        return true;
+                    var r = _client.Open();
+                    return r != null && r.IsSucceed;
+                }
+                catch
+                {
+                    return false;
+                }
+            }
+        }
+
+        public bool TryReadByte(string address, out byte value)
+        {
+            value = 0;
+            if (string.IsNullOrWhiteSpace(address) || !EnsureOpen())
+                return false;
+            try
+            {
+                var r = _client.ReadByte(NormalizeByteAddress(address));
+                if (r == null || !r.IsSucceed)
+                    return false;
+                value = r.Value;
+                return true;
+            }
+            catch
+            {
+                return false;
+            }
+        }
+
+        public bool TryWriteByte(string address, byte value)
+        {
+            if (string.IsNullOrWhiteSpace(address) || !EnsureOpen())
+                return false;
+            try
+            {
+                var r = _client.Write(NormalizeByteAddress(address), value);
+                return r != null && r.IsSucceed;
+            }
+            catch
+            {
+                return false;
+            }
+        }
+
+        public bool TryReadBool(string address, out bool value)
+        {
+            value = false;
+            if (string.IsNullOrWhiteSpace(address) || !EnsureOpen())
+                return false;
+            try
+            {
+                var r = _client.ReadBoolean(address.Trim());
+                if (r == null || !r.IsSucceed)
+                    return false;
+                value = r.Value;
+                return true;
+            }
+            catch
+            {
+                return false;
+            }
+        }
+
+        public bool TryWriteBool(string address, bool value)
+        {
+            if (string.IsNullOrWhiteSpace(address) || !EnsureOpen())
+                return false;
+            try
+            {
+                var r = _client.Write(address.Trim(), value);
+                return r != null && r.IsSucceed;
+            }
+            catch
+            {
+                return false;
+            }
+        }
+
+        public void Close()
+        {
+            lock (_sync)
+            {
+                try { _client?.Close(); }
+                catch { }
+                _client = null;
+            }
+        }
+
+        public void Dispose() => Close();
+
+        internal static string NormalizeByteAddress(string address)
+        {
+            var addr = address.Trim();
+            var m = BareDbByte.Match(addr);
+            return m.Success ? $"DB{m.Groups[1].Value}.DBB{m.Groups[2].Value}" : addr;
+        }
+
+        internal static SiemensVersion ParseVersion(string version)
+        {
+            if (string.IsNullOrWhiteSpace(version))
+                return SiemensVersion.S7_1500;
+            return Enum.TryParse(version.Replace("-", "_"), true, out SiemensVersion parsed)
+                ? parsed
+                : SiemensVersion.S7_1500;
+        }
+    }
+}