First steps PLCCom Modbus API for .NET

What is Modbus, anyway?

• developed with industrial applications in mind
• openly published and royalty-free
• easy to deploy and maintain
• moves raw bits or words without placing many restrictions on vendors

What provides PLCCom for Modbus?

• Access via TCP, UDP, RTU, RTU over TCP or ASCII
• integrated ModBus-Master components
• integrated ModBus-Slave components
• The internal routines are optimized for High-Performance-accesses Various recurring read accesses can be combined into a collection; thereby Modbus requests are combined to an absolute minimum.
• Optional 32-Bit Register-Modus to plotting 32-Bit-Numbers in a Register (Usually other tool only provide 16Bit-Register)
• Read and write all logiclly primitives .Net/Java-data types. Including converting with an adjustable method (e.g. Big-Endian, Little-Endian, etc.)
• Slave-component whit multiple listeners; that means it is possible to make any numbers of accesses to a Modbus Slave available at the same time e.g. TCP Port502, TCP Port503, UDP Port 502, etc.
• Extensive Logs incl. Record of all sent data
• Extensive example projects
• Master- und Slave-simulation to support your development and also helps for putting your programs into operation
• You receive a large collection of code examples to help and illustrate the connection of your program to a PLC. Usable on your own code.

Which system components require the PLCcom?

• Microsoft .NET Framework 4.7.2 or newer (.Net version) or
• Microsoft .NET Standard 2.1 or newer (.Net version) or
• Microsoft .NET Core 3.1 or newer (.Net version) or
• Microsoft .NET 5 or newer (.Net version) or
• Microsoft .NET 6 or newer (.Net version) or
• Microsoft .NET 7 or newer (.Net version) or
• Microsoft .NET 8 or newer (.Net version) or

• Visual Studio 2017 or newer (.Net version)

First steps PLCCom-ModBus-Master

Syntax: Create and initialize a Modbus-Master-Object

C#
VB
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ModbusMaster Device = new ModbusMaster("user","serial");
Device As ModbusMaster= new ModbusMaster("user","serial")

Syntax: Creating a Data-connector and bind to the Modbus-Master

C#
VB
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Device.SetConnector_TCP("192.168.1.21);
Device.SetConnector_TCP("192.168.1.21)

Syntax: Creat a Modbus-Request e.g. read / write data

C#
VB
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//read 10 holding register from adress 100
ReadRequest myReadRequest = RequestBuilder.ReadRequestBuilder.Create(1,  //Slave ID
        eReadFunction.F03_Read_Holding_Registers, // function
        100,          //Read start address
        eDataType.SHORT,       //Target Datatype
        10);          //quantity of objects to be read
'read 10 holding register from adress 100 '
Dim myReadRequest As ReadRequest = RequestBuilder.ReadRequestBuilder.Create(1,
          eReadFunction.F03_Read_Holding_Registers, _ 
          100, _ 
          eDataType.[SHORT], _ 
          10)

Syntax: Transfer the Request to Modbus-Master and receive the Result

C#
VB
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ReadResult res = Device.Read(myReadRequest);
Dim res As ReadResult = Device.Read(myReadRequest)

C#
VB
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//evaluate results
Console.WriteLine(DateTime.Now.ToString() + ": " + res.Message);

if (res.Quality == OperationResult.eQuality.GOOD)
{
    StringBuilder sb = new StringBuilder();
    foreach (ReadValue item in res.FetchValues())
     {
  sb.Append("Address " + item.Address.ToString() + " / Pos" + item.AddressPosition.ToString());
  sb.Append(" >> ");
  sb.Append(item.ToString());
  sb.Append(Environment.NewLine);
      }
     Console.WriteLine(sb.ToString());
  }
'evaluate results '
Console.WriteLine((DateTime.Now.ToString() & ": ") + res.Message)

If res.Quality = OperationResult.eQuality.GOOD Then 
   Dim sb As New StringBuilder()
   For Each item As ReadValue In res.FetchValues()
  sb.Append("Address " & item.Address.ToString() & " / Pos" & item.AddressPosition.ToString())
  sb.Append(" >> ")
  sb.Append(item.ToString()) 
  sb.Append(Environment.NewLine)
   Next   
   Console.WriteLine(sb.ToString())
 End If

First steps PLCCom- ModBus-Slave

Syntax: Create and initialize a Modbus-Slave-Object

C#
VB
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ModbusSlave Device = new ModbusSlave("user","serial",1); //SlaveID 1
Device As ModbusSlave = new ModbusSlave ("user","serial",1) 'SlaveID 1'

Syntax: Adding at least one Listener

C#
VB
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//add TCP listener
slave.AddOrReplaceListener_TCP("listener_tcp1", 502);

//add UDP listener
slave.AddOrReplaceListener_UDP("listener_udp1", 502);

//or add RTU listener
slave.AddOrReplaceListener_RTU("listener_rtu1",
        "COM1",
        eBaudrate.b9600,
        eDataBits.DataBits8,
        Parity.None,
        StopBits.One,
        Handshake.None);

//or add ASCII listener
slave.AddOrReplaceListener_ASCII("listener_ascii1",
        "COM2",
        eBaudrate.b9600,
        eDataBits.DataBits8,
        Parity.None,
        StopBits.One,
        Handshake.None);
'add TCP listener '
slave.AddOrReplaceListener_TCP("listener_tcp1", 502)

'add UDP listener '
slave.AddOrReplaceListener_UDP("listener_udp1", 502)

'or add RTU listener '
slave.AddOrReplaceListener_RTU("listener_rtu1",
        "COM1",    
        eBaudrate.b9600,
        eDataBits.DataBits8, 
        Parity.None, 
        StopBits.One, 
        Handshake.None) 

'or add ASCII listener '
slave.AddOrReplaceListener_ASCII("listener_ascii1",
        "COM2",  
        eBaudrate.b9600,
        eDataBits.DataBits8,
        Parity.None, 
        StopBits.One,
        Handshake.None)