FieldTalk Modbus Slave Library for .NET

Data Provider

A Data Provider acts as an agent between your Application and the Server Engine.

Modbus Slave classes collaboration diagram

After instantiating a Server Engine class of any protocol flavour, you have to associate it with a Data Provider by calling addDataTable and passing a reference of the Data Provider object.

C++

Copy

MbusRtuSlaveProtocol mbusServer = new MbusRtuSlaveProtocol();
MyDatatable dataTable = new MyDatatable();
mbusServer.addDataTable(1, dataTable);

Dim mbusServer As New MbusRtuSlaveProtocol()
Dim dataTable As New MyDatatable()
mbusServer.addDataTable(1, dataTable)

To create an application specific Data Provider derive a new class from MbusDataTableInterface and override the required data access methods.

A minimal Data Provider which realises a Modbus slave with read access to holding registers would be:

C++

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class MyDatatable: MbusDataTableInterface
{
    // Override readHoldingRegistersTable method:
    protected override bool readHoldingRegistersTable(Int32 startRef, Int16[] regArr)
    {
        ... your application specific implementation
    }
}

Class MyDatatable
    Inherits MbusDataTableInterface
    ' Override readHoldingRegistersTable method:
    Protected Overrides Function readHoldingRegistersTable(ByVal startRef As Int32, ByVal regArr() As Int16) As Boolean
        ... your application specific implementation
    End Function
End Class

FieldTalk Modbus Slave Library for .NET
Library version 2.11.0