Modbus Protocol

The Modbus protocol is a data communications standard that has grown to become the accepted standard messaging structure throughout the industrial and manufacturing industries. Modbus makes use of TCP/IP (the standard internet protocol) and was first developed by Modicon. Modbus is an open source protocol that is maintained by the Modbus Organization. The Modbus protocol was designed to provide master-slave client-server communications. Modbus is commonly used to handle communication with field devices. There are over 7 million Modbus nodes within the US and Europe, with hundreds of Modbus hardware devices.

Modbus Gateway Providers

• FieldServer Technologies: a protocol gateway provider dedicated to meeting the interoperability needs of the industrial market. FieldServer offers Modbus gateway solutions and has an extensive protocol library that includes Modbus protocol drivers as well as Modbus gateways. FieldServer enable communication between devices with non-compatible protocols. The Fieldserver Modbus library includes Modbus RTU, Modbus TCP, Modbus Plus, Modbus ASCII, and many more.
• Protocessor: providing protocol devices for equipment manufacturers, including both embedded and external solutions. Protocessor provides Modbus gateways making use of the extensive FieldServer library. Protocessor offers embedded Modbus gateways, as well as a Modbus protocol gateway daughter card and external serial/ethernet for fast adaption to Modbus.

Common Modbus Uses

Modbus is commonly used as a communications protocol throughout the manufacturing sectors of the industrial market and can be used to both monitor and program field devices. Modbus is an essential component of industrial automation, especially where wireless communication is necessary. Industries that make heavy use of the Modbus protocol include:

• Transportation industry
• Building automation
• Energy industry

Advantages of the Modbus Protocol

Two of the primary advantages of the Modbus protocol is that it is entirely open source (thus free of licensing costs) and that it is built on an Ethernet network. The fact that Modbus is built on the ethernet physical layer means that the current falling costs and dramatically increasing capabilities of ethernet will immediately and directly benefit Modbus as well. Further, Modbus makes use of standard Ethernet TCP/IP, meaning that unique chipsets are not needed to enable Modbus communications -- the standard PC can communication via Ethernet with a Modbus device.