AMWD.Protocols.Modbus/docs/articles/getting-started.md

Getting Started

To begin, you need at least the Common package.

In this package you'll find everything you need to implement you own client as the package contains the protocol implementations (TCP, RTU and ASCII).

The ModbusClientBase is the place, where most of the magic happens. In this base client you have all known (and implemented) methods to request a device.

The Protocol implementations are the other magic place to be, as there the request will be converted into bits and bytes, before they get transfered.

Using a TCP client

To use a TCP Modbus client, you need the Common package and the TCP package installed.

using AMWD.Protocols.Modbus.Common;
using AMWD.Protocols.Modbus.Common.Contracts;
using AMWD.Protocols.Modbus.Common.Protocols;
using AMWD.Protocols.Modbus.Tcp;

namespace ConsoleApp;

internal class Program
{
	string hostname = "modbus-device.internal";
	int port = 502;

	byte unitId = 5;
	ushort startAddress = 19000;
	ushort count = 2;

	using var client = new ModbusTcpClient(hostname, port);
	await client.ConnectAsync(CancellationToken.None);

	var holdingRegisters = await client.ReadHoldingRegistersAsync(unitId, startAddress, count);
	float voltage = holdingRegisters.GetSingle();

	Console.WriteLine($"The voltage of the device #{unitId} between L1 and N is {voltage:N2}V.");
}

This will automatically create a TCP client using the TCP protocol. If you want to change the protocol sent over TCP, you can specify it:

// [...] other code

using var client = new ModbusTcpClient(hostname, port)
{
	Protocol = new RtuProtocol()
};

// [...] other code

Using a Serial client

To use a Serial Modbus client, you need the Common package and the Serial package installed.

using AMWD.Protocols.Modbus.Common;
using AMWD.Protocols.Modbus.Common.Contracts;
using AMWD.Protocols.Modbus.Common.Protocols;
using AMWD.Protocols.Modbus.Serial;

namespace ConsoleApp;

internal class Program
{
	string serialPort = "/dev/ttyUSB0";

	byte unitId = 5;
	ushort startAddress = 19000;
	ushort count = 2;

	using var client = new ModbusSerialClient(serialPort);
	await client.ConnectAsync(CancellationToken.None);

	var holdingRegisters = await client.ReadHoldingRegistersAsync(unitId, startAddress, count);
	float voltage = holdingRegisters.GetSingle();

	Console.WriteLine($"The voltage of the device #{unitId} between L1 and N is {voltage:N2}V.");
}

This will automatically create a Serial client using the RTU protocol. If you want to change the protocol sent over serial line, you can specify it:

// [...] other code

using var client = new ModbusSerialClient(serialPort)
{
	Protocol = new AsciiProtocol()
};

// [...] other code