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Add ConnectionGroupId attribute to Tag class #479

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26 changes: 26 additions & 0 deletions docs/libplctag.md
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Expand Up @@ -34,6 +34,32 @@ myTag.Write();
Console.WriteLine($"Updated value: {updatedValue}");
```

To force separate channels to the same PLC from one process, set different `ConnectionGroupId` values:

```csharp
var channel1Tag = new Tag()
{
Name = "SomeDINT",
Gateway = "10.10.10.10",
Path = "1,0",
PlcType = PlcType.ControlLogix,
Protocol = Protocol.ab_eip,
ConnectionGroupId = 1
};

var channel2Tag = new Tag()
{
Name = "SomeOtherDINT",
Gateway = "10.10.10.10",
Path = "1,0",
PlcType = PlcType.ControlLogix,
Protocol = Protocol.ab_eip,
ConnectionGroupId = 2
};
```

If `ConnectionGroupId` is not set, the channel is shared.

See the examples projects for further detail and usage:

* [C# (.NET)](../examples/CSharp%20DotNetCore/)
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2 changes: 1 addition & 1 deletion examples/CSharp NativeImport/CallbackEx.cs
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Expand Up @@ -29,7 +29,7 @@ public static void Run()
{

// Create the tag handle
var tagHandle = plctag.plc_tag_create("protocol=ab_eip&gateway=127.0.0.1&path=1,0&plc=LGX&elem_size=4&elem_count=1&name=MyTag[0]", 1000);
var tagHandle = plctag.plc_tag_create("protocol=ab_eip&gateway=127.0.0.1&path=1,0&plc=LGX&elem_size=4&elem_count=1&name=MyTag[0]&connection_group_id=1", 1000);
var statusBeforeRead = plctag.plc_tag_status(tagHandle);
if (statusBeforeRead != 0)
{
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3 changes: 2 additions & 1 deletion examples/CSharp NativeImport/Multithread.cs
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Expand Up @@ -13,7 +13,8 @@ namespace NativeImport_Examples
{
class Multithread
{
const string TAG_PATH = "protocol=ab_eip&gateway=192.168.0.10&path=1,0&plc=LGX&elem_size=4&elem_count=1&name=MY_DINT";
// Optional: set connection_group_id to isolate this tag's channel from other tags in the same process.
const string TAG_PATH = "protocol=ab_eip&gateway=192.168.0.10&path=1,0&plc=LGX&elem_size=4&elem_count=1&name=MY_DINT&connection_group_id=1";
const int ELEM_COUNT = 1;
const int ELEM_SIZE = 4;
const int DATA_TIMEOUT = 2000;
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7 changes: 4 additions & 3 deletions examples/CSharp NativeImport/NativeImportExample.cs
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Expand Up @@ -21,7 +21,8 @@ public static void Run()
//Please reference the libplctag documentation for API and usage


var tagHandle = plctag.plc_tag_create("protocol=ab_eip&gateway=192.168.0.10&path=1,0&plc=LGX&elem_size=4&elem_count=1&name=MY_DINT", 1000);
// Optional: set connection_group_id to create a separate channel to the same PLC when needed.
var tagHandle = plctag.plc_tag_create("protocol=ab_eip&gateway=192.168.0.10&path=1,0&plc=LGX&elem_size=4&elem_count=1&name=MY_DINT&connection_group_id=1", 1000);

while (plctag.plc_tag_status(tagHandle) == 1)
{
Expand Down Expand Up @@ -54,7 +55,7 @@ public static void Run()
public static void RunCallbackExample()
{

var tagHandle = plctag.plc_tag_create("protocol=ab_eip&gateway=192.168.0.10&path=1,0&plc=LGX&elem_size=4&elem_count=1&name=MY_DINT", 1000);
var tagHandle = plctag.plc_tag_create("protocol=ab_eip&gateway=192.168.0.10&path=1,0&plc=LGX&elem_size=4&elem_count=1&name=MY_DINT&connection_group_id=1", 1000);

while (plctag.plc_tag_status(tagHandle) == 1)
{
Expand Down Expand Up @@ -105,7 +106,7 @@ public static void RunLoggerExample()
Console.WriteLine($"Something went wrong {statusAfterRegistration}");
}

var tagHandle = plctag.plc_tag_create("protocol=ab_eip&gateway=127.0.0.1&path=1,0&plc=LGX&elem_size=4&elem_count=1&name=MyTag&debug=4", 1000);
var tagHandle = plctag.plc_tag_create("protocol=ab_eip&gateway=127.0.0.1&path=1,0&plc=LGX&elem_size=4&elem_count=1&name=MyTag&debug=4&connection_group_id=1", 1000);

while (plctag.plc_tag_status(tagHandle) == 1)
{
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18 changes: 18 additions & 0 deletions src/libplctag.Tests/OtherTests.cs
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Expand Up @@ -68,5 +68,23 @@ public void Attribute_string_does_not_contain_unset_properties()
nativeTag.Verify(m => m.plc_tag_create_ex(expectedAttributeString, It.IsAny<NativeImport.plctag.callback_func_ex>(), It.IsAny<IntPtr>(), It.IsAny<int>()), Times.Once);

}

[Fact]
public void Attribute_string_contains_connection_group_id_when_set()
{
// Arrange
var nativeTag = new Mock<INative>();
var tag = new Tag(nativeTag.Object)
{
ConnectionGroupId = 7,
};

// Act
tag.Initialize();

// Assert
var expectedAttributeString = "connection_group_id=7";
nativeTag.Verify(m => m.plc_tag_create_ex(expectedAttributeString, It.IsAny<NativeImport.plctag.callback_func_ex>(), It.IsAny<IntPtr>(), It.IsAny<int>()), Times.Once);
}
}
}
23 changes: 23 additions & 0 deletions src/libplctag/Tag.cs
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Expand Up @@ -47,6 +47,7 @@ public sealed class Tag : IDisposable
private bool? _allowFieldResize;
private int? _readCacheMillisecondDuration;
private uint? _maxRequestsInFlight;
private int? _connectionGroupId;
private TimeSpan _timeout = defaultTimeout;
private TimeSpan? _autoSyncReadInterval;
private TimeSpan? _autoSyncWriteInterval;
Expand Down Expand Up @@ -630,6 +631,27 @@ public uint? MaxRequestsInFlight
set => SetField(ref _maxRequestsInFlight, value);
}

/// <summary>
/// [OPTIONAL]
/// A user-defined identifier, in the form of an integer, used to separate PLC connections into distinct groups.
/// </summary>
///
/// <remarks>
/// By default, tags that share the same <see cref="Gateway"/> and <see cref="Path"/> are
/// multiplexed over a single shared connection/session to the PLC.
/// Setting <see cref="ConnectionGroupId"/> to a distinct value forces those tags onto their
/// own, independent connection, even when the gateway and path are otherwise identical.
/// This allows a single process to maintain multiple simultaneous connections to the same PLC,
/// for example to isolate latency-sensitive polling from bulk/background requests.
/// Like the other connection attributes, this cannot be changed after the tag is initialized.
/// Note: Leave unset to preserve existing connection sharing behavior.
/// </remarks>
public int? ConnectionGroupId
{
get => GetField(ref _connectionGroupId);
set => SetField(ref _connectionGroupId, value);
}


public void Dispose()
{
Expand Down Expand Up @@ -1207,6 +1229,7 @@ string FormatTimeSpan(TimeSpan? timespan)
{ "str_pad_bytes", StringPadBytes?.ToString() },
{ "str_total_length", StringTotalLength?.ToString() },
{ "max_requests_in_flight", MaxRequestsInFlight?.ToString() },
{ "connection_group_id", ConnectionGroupId?.ToString() },
{ "allow_field_resize", FormatNullableBoolean(AllowFieldResize) },
};

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