PlcComm.Slmp 0.1.13

SLMP Protocol for .NET

High-level SLMP helpers for Mitsubishi PLC communication over Binary 3E and 4E frames.

The recommended user surface is the extension-method layer:

• SlmpClientFactory.OpenAndConnectAsync
• SlmpConnectionOptions
• ReadTypedAsync / WriteTypedAsync
• ReadWordsSingleRequestAsync / ReadDWordsSingleRequestAsync
• ReadWordsChunkedAsync / ReadDWordsChunkedAsync
• WriteBitInWordAsync
• ReadNamedAsync
• WriteNamedAsync
• PollAsync
• SlmpAddress.Normalize
• ReadDeviceRangeCatalogAsync

Quick Start

Installation

• Package page: https://www.nuget.org/packages/PlcComm.Slmp/

dotnet add package PlcComm.Slmp

Or add a package reference directly:

<PackageReference Include="PlcComm.Slmp" Version="0.1.13" />

Recommended High-Level Usage

using PlcComm.Slmp;

var options = new SlmpConnectionOptions("192.168.250.100", SlmpPlcFamily.IqR)
{
    Port = 1025,
};

await using var client = await SlmpClientFactory.OpenAndConnectAsync(options);

var snapshot = await client.ReadNamedAsync(["D100", "D200:F", "D50.3"]);
Console.WriteLine(snapshot["D100"]);
Console.WriteLine(snapshot["D200:F"]);
Console.WriteLine(snapshot["D50.3"]);

Supported PLC Registers

Start with these public high-level families first:

• word devices: D, SD, R, ZR, TN, CN
• bit devices: M, X, Y, SM, B
• typed forms: D200:F, D300:L, D100:S
• mixed snapshot forms: D50.3, D100, D200:F
• current-value long families: LTN, LSTN, LCN
• 32-bit index register: LZ

See the full public table in Supported PLC Registers.

For live PLC-dependent device limits resolved from a user-selected PLC family plus family SD registers, see Device Range Catalog.

Long Current / 32-bit Values

LTN, LSTN, and LCN are not normal 16-bit word devices in the high-level API. They represent 32-bit current values. LZ is also a 32-bit device. Use the typed or named API with :D or :L:

var timer = await client.ReadTypedAsync("LTN100", "L");
await client.WriteTypedAsync("LTN100", "L", 1234);

var lz = await client.ReadTypedAsync("LZ0", "D");
var snapshot = await client.ReadNamedAsync(["LTN100:L", "LSTN10:D", "LCN0:L", "LZ0:D"]);
await client.WriteNamedAsync(new Dictionary<string, object>
{
    ["LCN0:L"] = 10,
    ["LZ0:D"] = 0,
});

LCN current values use random dword access in the high-level helpers. The low-level word block APIs intentionally reject LTN / LSTN / LCN / LZ as word writes and random word entries. Direct DWord reads/writes are also rejected for these families so the 32-bit route is selected explicitly through ReadTypedAsync / ReadNamedAsync or WriteTypedAsync / WriteNamedAsync.

Contact and coil devices in the long families, such as LTS, LTC, LSTS, LSTC, LCS, and LCC, are bit-style addresses. Do not treat them as current-value words. ReadLtsStatesAsync, ReadLtcStatesAsync, ReadLstsStatesAsync, and ReadLstcStatesAsync read the LTN / LSTN 4-word status block and use the third word (b1 for contact, b0 for coil). LCS and LCC reads use direct bit read through the typed/named helpers. For LTS, LTC, LSTS, LSTC, LCS, and LCC writes, WriteTypedAsync / WriteNamedAsync select the random bit write route (0x1402) instead of the contiguous bit write route (0x1401).

Route guard note: direct bit read/write (0x0401 / 0x1401) and Read Random (0x0403) are intentionally rejected for LTS, LTC, LSTS, and LSTC before a PLC request is sent. Direct bit write (0x1401) is also rejected for LCS and LCC; use WriteTypedAsync / WriteNamedAsync so 0x1402 is selected.

Device Range Catalog

Use ReadDeviceRangeCatalogAsync after opening a connection with a selected SlmpPlcFamily. The catalog reports whether each device is supported, its point count, lower bound, upper bound, display range, notation, and source.

var catalog = await client.ReadDeviceRangeCatalogAsync();
var stn = catalog.Entries.First(entry => entry.Device == "STN");

if (!stn.Supported || stn.PointCount == 0)
{
    Console.WriteLine("STN is unavailable in the current PLC settings.");
}

Applications should use this catalog to clamp monitor scroll ranges and reject out-of-range reads or writes before issuing SLMP commands.

Public Documentation

• Getting Started
• Supported PLC Registers
• Device Range Catalog
• Latest Communication Verification
• User Guide
• Samples
• High-Level API Contract

Maintainer-only notes and retained evidence live under internal_docs/.

High-Level API Guide

Typed Values

float temperature = (float)await client.ReadTypedAsync("D200", "F");
int position = (int)await client.ReadTypedAsync("D300", "L");

await client.WriteTypedAsync("D100", "U", (ushort)42);
await client.WriteTypedAsync("D200", "F", 3.14f);
await client.WriteTypedAsync("D300", "L", -100);
await client.WriteTypedAsync("LTN100", "L", 1000);

Mixed Reads

var snapshot = await client.ReadNamedAsync(
[
    "D100",
    "D200:F",
    "D300:L",
    "D50.3",
]);

Use .bit notation only with word devices such as D50.3. Address bit devices directly as M1000, M1001, X20, or Y20.

Use :D or :L with LTN, LSTN, and LCN.

Development

run_ci.bat
build_docs.bat
release_check.bat

Pack the NuGet package locally:

dotnet pack src\PlcComm.Slmp\PlcComm.Slmp.csproj -c Release

License

Distributed under the MIT License.