Phase 3 PR 62 -- Siemens S7 native driver project scaffold (S7comm via S7netplus). First non-Modbus in-process driver. Creates src/ZB.MOM.WW.OtOpcUa.Driver.S7 (.NET 10, x64 -- S7netplus is managed, no bitness constraint like MXAccess) + tests/ZB.MOM.WW.OtOpcUa.Driver.S7.Tests + slnx entries. Depends on S7netplus 0.20.0 which is the latest version on NuGet resolvable in this cache (0.21.0 per driver-specs.md is not yet published; 0.20.0 covers the same Plc+CpuType+ReadAsync surface). S7DriverOptions captures the connection settings documented in driver-specs.md \u00A75: Host, Port (default 102 ISO-on-TCP), CpuType (default S71500 per most-common deployment), Rack=0, Slot=0 (S7-1200/1500 onboard PN convention; S7-300/400 operators must override to slot 2 or 3), Timeout=5s, Tags list + Probe settings with default MW0 probe address. S7TagDefinition uses S7.Net-style address strings (DB1.DBW0, M0.0, I0.0, QD4) with an S7DataType enum (Bool, Byte, Int16, UInt16, Int32, UInt32, Int64, UInt64, Float32, Float64, String, DateTime -- the full type matrix from the spec); StringLength defaults to 254 (S7 STRING max). S7Driver implements the IDriver-only subset per the PR plan: InitializeAsync opens a managed Plc with the configured CpuType + Host + Rack + Slot, pins WriteTimeout / ReadTimeout on the underlying TcpClient, awaits Plc.OpenAsync with a linked CTS bounded by Options.Timeout so the ISO handshake itself respects the configured bound; health transitions Unknown -> Initializing -> Healthy on success or Unknown -> Initializing -> Faulted on handshake failure, with a best-effort Plc.Close() on the faulted path so retries don't leak the TcpClient. ShutdownAsync closes the Plc and flips health back to Unknown. DisposeAsync routes through ShutdownAsync + disposes the SemaphoreSlim. Internal Gate + Plc accessors are exposed to the test project (InternalsVisibleTo) so PRs 63-65 can stack read/write/subscribe on the same serialization semaphore per the S7netplus documented 'one Plc per PLC, SemaphoreSlim-serialized' pattern. ITagDiscovery, IReadable, IWritable, ISubscribable, IHostConnectivityProbe are all deliberately omitted from this PR -- they depend on the S7AddressParser (PR 63) and land sequenced in PRs 64-65. Unit tests (S7DriverScaffoldTests, 5 facts): default options target S7-1500 / port 102 / slot 0, default probe interval 5s, tag defaults to writable with StringLength 254, driver reports DriverType=S7 + Unknown health pre-init, Initialize against RFC-5737 reserved IP 192.0.2.1 with 250ms timeout transitions to Faulted and throws (tests the connect-failure path doesn't leave the driver in an ambiguous state). 5/5 pass. dotnet build ZB.MOM.WW.OtOpcUa.slnx: 0 errors. No regression in Modbus / Galaxy suites. PR 63 ships S7AddressParser next, PR 64 wires IReadable/IWritable over S7netplus, PR 65 adds discovery + polling-overlay subscribe + probe.

src/ZB.MOM.WW.OtOpcUa.Driver.S7/S7DriverOptions.cs

@@ -0,0 +1,112 @@
+using S7NetCpuType = global::S7.Net.CpuType;
+
+namespace ZB.MOM.WW.OtOpcUa.Driver.S7;
+
+/// <summary>
+///     Siemens S7 native (S7comm / ISO-on-TCP port 102) driver configuration. Bound from the
+///     driver's <c>DriverConfig</c> JSON at <c>DriverHost.RegisterAsync</c>. Unlike the Modbus
+///     driver the S7 driver uses the PLC's *native* protocol — port 102 ISO-on-TCP rather
+///     than Modbus's 502, and S7-specific area codes (DB, M, I, Q) rather than holding-
+///     register / coil tables.
+/// </summary>
+/// <remarks>
+///     <para>
+///         The driver requires <b>PUT/GET communication enabled</b> in the TIA Portal
+///         hardware config for S7-1200/1500. The factory default disables PUT/GET access,
+///         so a driver configured against a freshly-flashed CPU will see a hard error
+///         (S7.Net surfaces it as <c>Plc.ReadAsync</c> returning <c>ErrorCode.Accessing</c>).
+///         The driver maps that specifically to <c>BadNotSupported</c> and flags it as a
+///         configuration alert rather than a transient fault — blind Polly retry is wasted
+///         effort when the PLC will keep refusing every request.
+///     </para>
+///     <para>
+///         See <c>docs/v2/driver-specs.md</c> §5 for the full specification.
+///     </para>
+/// </remarks>
+public sealed class S7DriverOptions
+{
+    /// <summary>PLC IP address or hostname.</summary>
+    public string Host { get; init; } = "127.0.0.1";
+
+    /// <summary>TCP port. ISO-on-TCP is 102 on every S7 model; override only for unusual NAT setups.</summary>
+    public int Port { get; init; } = 102;
+
+    /// <summary>
+    ///     CPU family. Determines the ISO-TSAP slot byte that S7.Net uses during connection
+    ///     setup — pick the family that matches the target PLC exactly.
+    /// </summary>
+    public S7NetCpuType CpuType { get; init; } = S7NetCpuType.S71500;
+
+    /// <summary>
+    ///     Hardware rack number. Almost always 0; relevant only for distributed S7-400 racks
+    ///     with multiple CPUs.
+    /// </summary>
+    public short Rack { get; init; } = 0;
+
+    /// <summary>
+    ///     CPU slot. Conventions per family: S7-300 = slot 2, S7-400 = slot 2 or 3,
+    ///     S7-1200 / S7-1500 = slot 0 (onboard PN). S7.Net uses this to build the remote
+    ///     TSAP. Wrong slot → connection refused during handshake.
+    /// </summary>
+    public short Slot { get; init; } = 0;
+
+    /// <summary>Connect + per-operation timeout.</summary>
+    public TimeSpan Timeout { get; init; } = TimeSpan.FromSeconds(5);
+
+    /// <summary>Pre-declared tag map. S7 has a symbol-table protocol but S7.Net does not expose it, so the driver operates off a static tag list configured per-site. Address grammar documented in S7AddressParser (PR 63).</summary>
+    public IReadOnlyList<S7TagDefinition> Tags { get; init; } = [];
+
+    /// <summary>
+    ///     Background connectivity-probe settings. When enabled, the driver runs a tick loop
+    ///     that issues a cheap read against <see cref="S7ProbeOptions.ProbeAddress"/> every
+    ///     <see cref="S7ProbeOptions.Interval"/> and raises <c>OnHostStatusChanged</c> on
+    ///     Running ↔ Stopped transitions.
+    /// </summary>
+    public S7ProbeOptions Probe { get; init; } = new();
+}
+
+public sealed class S7ProbeOptions
+{
+    public bool Enabled { get; init; } = true;
+    public TimeSpan Interval { get; init; } = TimeSpan.FromSeconds(5);
+    public TimeSpan Timeout { get; init; } = TimeSpan.FromSeconds(2);
+
+    /// <summary>
+    ///     Address to probe for liveness. DB1.DBW0 is the convention if the PLC project
+    ///     reserves a small fingerprint DB for health checks (per <c>docs/v2/s7.md</c>);
+    ///     if not, pick any valid Merker word like <c>MW0</c>.
+    /// </summary>
+    public string ProbeAddress { get; init; } = "MW0";
+}
+
+/// <summary>
+///     One S7 variable as exposed by the driver. Addresses use S7.Net syntax — see
+///     <c>S7AddressParser</c> (PR 63) for the grammar.
+/// </summary>
+/// <param name="Name">Tag name; OPC UA browse name + driver full reference.</param>
+/// <param name="Address">S7 address string, e.g. <c>DB1.DBW0</c>, <c>M0.0</c>, <c>I0.0</c>, <c>QD4</c>. Grammar documented in <c>S7AddressParser</c> (PR 63).</param>
+/// <param name="DataType">Logical data type — drives the underlying S7.Net read/write width.</param>
+/// <param name="Writable">When true the driver accepts writes for this tag.</param>
+/// <param name="StringLength">For <c>DataType = String</c>: S7-string max length. Default 254 (S7 max).</param>
+public sealed record S7TagDefinition(
+    string Name,
+    string Address,
+    S7DataType DataType,
+    bool Writable = true,
+    int StringLength = 254);
+
+public enum S7DataType
+{
+    Bool,
+    Byte,
+    Int16,
+    UInt16,
+    Int32,
+    UInt32,
+    Int64,
+    UInt64,
+    Float32,
+    Float64,
+    String,
+    DateTime,
+}