Usage guide

Recommended entry points

API	Use
SlmpConnectionOptions	Holds host, profile, port, transport, timeout, target, and monitoring timer settings.
SlmpClientFactory.OpenAndConnectAsync	Opens a connected QueuedSlmpClient from SlmpConnectionOptions.
ReadTypedAsync	Reads one typed scalar such as D100 as U, S, D, L, or F.
WriteTypedAsync	Writes one typed scalar.
ReadNamedAsync	Reads a mixed snapshot of named addresses.
WriteNamedAsync	Writes a named set of values.
ReadWordsSingleRequestAsync / ReadDWordsSingleRequestAsync	Reads one contiguous block in one protocol request.
ReadWordsChunkedAsync / ReadDWordsChunkedAsync	Reads an explicitly chunked contiguous block.
WriteBitInWordAsync	Sets or clears one bit in a word device.
PollAsync	Repeats a named snapshot on an async interval.
SlmpAddress	Parses, formats, and normalizes SLMP address text.

Connection

using System;
using PlcComm.Slmp;

var options = new SlmpConnectionOptions("192.168.250.100", SlmpPlcProfile.IqR)
{
    Port = 1025,
    Timeout = TimeSpan.FromSeconds(3),
    Transport = SlmpTransportMode.Tcp,
    Target = new SlmpTargetAddress(Station: 0xFF, ModuleIo: 0x03FF),
    MonitoringTimer = 0x0010,
};

await using var client = await SlmpClientFactory.OpenAndConnectAsync(options);
Console.WriteLine($"{client.FrameType} {client.CompatibilityMode}");

Read a single value

Type suffix	.NET value	PLC size
U	ushort	1 word
S	short	1 word
D	uint	2 words
L	int	2 words
F	float	2 words

using System;
using PlcComm.Slmp;

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

await using var client = await SlmpClientFactory.OpenAndConnectAsync(options);
var value = await client.ReadTypedAsync("D100", "U");
Console.WriteLine($"D100 = {value}");

Write a single value

using System;
using PlcComm.Slmp;

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

await using var client = await SlmpClientFactory.OpenAndConnectAsync(options);
await client.WriteTypedAsync("D100", "U", (ushort)123);
Console.WriteLine("Wrote D100.");

Named snapshot

using System;
using PlcComm.Slmp;

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

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

foreach (var (address, value) in snapshot)
{
    Console.WriteLine($"{address} = {value}");
}

Block reads

using System;
using PlcComm.Slmp;

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

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

ushort[] words = await client.ReadWordsSingleRequestAsync("D0", 10);
uint[] dwords = await client.ReadDWordsSingleRequestAsync("D200", 4);
ushort[] chunkedWords = await client.ReadWordsChunkedAsync("D1000", 1000, maxWordsPerRequest: 480);
uint[] chunkedDwords = await client.ReadDWordsChunkedAsync("D2000", 200, maxDwordsPerRequest: 240);

Console.WriteLine($"words={words.Length}, dwords={dwords.Length}");
Console.WriteLine($"chunked words={chunkedWords.Length}, chunked dwords={chunkedDwords.Length}");

Bit in word

Use WriteBitInWordAsync when a PLC stores flags inside a word. Use .n notation such as D50.3 when reading the same bit in a named snapshot.

using System;
using PlcComm.Slmp;

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

await using var client = await SlmpClientFactory.OpenAndConnectAsync(options);
await client.WriteBitInWordAsync("D50", bitIndex: 3, value: true);
var snapshot = await client.ReadNamedAsync(["D50.3"]);
Console.WriteLine($"D50.3 = {snapshot["D50.3"]}");

Polling

using System;
using System.Threading;
using PlcComm.Slmp;

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

await using var client = await SlmpClientFactory.OpenAndConnectAsync(options);
using var cts = new CancellationTokenSource(TimeSpan.FromSeconds(10));

await foreach (var snapshot in client.PollAsync(["D100", "D200:F", "D50.3"], TimeSpan.FromSeconds(1), cts.Token))
{
    Console.WriteLine($"D100 = {snapshot["D100"]}");
}

Device range catalog

ReadDeviceRangeCatalogAsync reads live device range bounds from your PLC after you connect with an explicit PLC profile. It does not auto-discover the profile.

using System;
using System.Linq;
using PlcComm.Slmp;

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

await using var client = await SlmpClientFactory.OpenAndConnectAsync(options);
var catalog = await client.ReadDeviceRangeCatalogAsync();
var row = catalog.Entries.First(entry => entry.Device == "D");

Console.WriteLine($"{row.Device}: supported={row.Supported}, range={row.AddressRange}");

Long device families

LTN, LSTN, LCN, and LZ are 32-bit families. Always use :D or :L in named addresses, or pass D or L as the ReadTypedAsync / WriteTypedAsync dtype.

using System;
using PlcComm.Slmp;

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

await using var client = await SlmpClientFactory.OpenAndConnectAsync(options);
var current = await client.ReadTypedAsync("LTN0", "D");
var snapshot = await client.ReadNamedAsync(["LTN0:D", "LSTN0:L", "LCN0:D", "LZ0:L"]);

Console.WriteLine($"LTN0 = {current}");
Console.WriteLine($"LCN0:D = {snapshot["LCN0:D"]}");

Caution: Plain word access to LTN, LSTN, LCN, and LZ is rejected by the library.

Address reference

Form	Example	Meaning
Plain word	D100	Unsigned 16-bit word by default.
Plain bit	M1000	Boolean bit value.
:U	D100:U	Unsigned 16-bit word.
:S	D100:S	Signed 16-bit word.
:D	D200:D	Unsigned 32-bit value.
:L	D200:L	Signed 32-bit value.
:F	D200:F	Float32 value.
.n	D50.3	Bit n inside one word, where n is hexadecimal 0 to F.