libmodbus: Modbus Library from Raditex Control
The rSCADA libmodbus is a software library for Modbus TCP and Modbus UDP. The Modbus protocol is an industrial standard for communicating with control and data acquisition hardware. It can be used with a number of transport protocols, such as serial lines, TCP, UDP, etc. With this Modbus library, we aim to provide support for the TCP/UDP transport layers, as these two are the most commonly used nowadays.
See, e.g., the Wiki page for Modbus or the official Modbus web site for more information about the Modbus protocol and its uses. Of particular importance is the Modbus Application Protocol specification (V1.1b).
Features
The rSCADA Modbus library currently only support a subset of the Modbus standard. The feature set is planned to be expanded in upcoming releases.
The rSCADA Modbus library is split into two main parts: the protocol layer and the transport layer. The protocol layer is responsible for parsing and packing Modbus packets, and the transport layer is responsible for sending and receiving packets. There are two transport-layer implementations: one for TCP/IP and one for UDP/IP communication.
A summary of the main features and characteristics:
- Support for both client and server side Modbus TCP
- Support for both client and server side Modbus UDP
- Support for the following Modbus functions:
- READ_COIL_STATUS, READ_INPUT_STATUS, READ_HOLDING_REGISTER, READ_INPUT_REGISTERS, FORCE_SINGLE_COIL, PRESET_SINGLE_REGISTER
Download
You can browse the source code here, or download the latest source. The current version of the library is 0.2.
License
The libmbus library is a component of RaditexSCADA that is published as open source, and it is free for anyone to use as long as due credit it given to RaditexSCADA and Raditex Control in derivative work based on the libmodbus library.
