FieldTalk Modbus® Master Protocol Library
C++ Editions
FOCUS Software Engineering

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General Description

Introduction

This FieldTalk Modbus® Master Library - C++ Editions are a C++ class library suite which provides connectivity to Modbus slave compatible devices and applications.

Typical applications are supervisory control systems, data concentrators and gateways, user interfaces and factory information systems.

Features:

Library Structure

The library is organised into one class for each Modbus master protocol flavour and a common base class, which applies to all protocol flavours. Because the two serial protocols ASCII and RTU share some common code, an intermediate base class implements the functions specific to serial protocols.

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The base class MbusMasterFunctions contains all protocol unspecific functions, in particular the data and control functions defined by Modbus. All protocol flavours inherit from this base class.

The class MbusAsciiMasterProtocol implements the Modbus ASCII protocol, the class MbusRtuMasterProtocol implements the Modbus RTU protocol. The class MbusTcpMasterProtocol implements the MODBUS/TCP protocol and the class MbusRtuOverTcpMasterProtocol the Encapsulated Modbus RTU master protocol (also known as RTU over TCP or RTU/IP).

In order to use one of the three master protocols, the desired protocol flavour class has to be instantiated:

MbusRtuMasterProtocol mbusProtocol;

After a protocol object has been declared and opened, data and control functions can be used:

mbusProtocol.writeSingleRegister(slaveId, startRef, 1234);

Overview