Comparison between HART, Profibus and Foundation Fieldbus

What is HART?

HART is “Highway Addressable Remote Transducer”, which is a communication protocol for control field devices that work with a 4-20 mA control signal.

The HART® protocol uses a 1200 baud frequency shift (FSK) encoding based on the Bell 202 standard to superimpose digital information on the conventional 4-20 mA analog signal. Maintained by an independent organization, HART® Communication Foundation, the HART® protocol is an industry standard developed to define the communication protocol between intelligent field devices and a control system.

HART is the oldest and most widely used communication protocol.

Main features:

  • HART will support all major field device

  • HART works in existing 4-20mA loop, to co-exist with digital communication on existing 2-wire loops.

  • It provides important information for installation and maintenance, such as tag identification, measurement values, range and range data, product information and diagnostics.

  • Can save cable through using multidrop

  • Reduces operating costs via improved management and utilisation of smart instrument networks.

What is Profibus?

Profibus stands for Process field bus and DP stands for Decentralized peripherals. Profibus collects data from all types of field devices and operator terminals communicate with the automation systems via an efficient, real-time communication system. As with data, alarms, parameters and diagnostic data can also be transmitted cyclically if necessary.

Profibus® can be used for both high-speed time-critical applications and complex communication tasks.Profibus® offers functionally graduated communication protocols for DP and FMS.

Main features:

  • Profibus® offers functionally graduated communication protocols DP and FMS.

  • The transmission technologies RS-485, IEC 1158-2 or fibre optics can be used.

  • The information flow requires large data packet flow, such as Intranet and Internet via TCP/IP and Ethernet.

  • High functionality for automation needs from drives to instruments.

  • Transmission technologies RS-485, IEC 1158-2 or fibre optics can be used.

What is Foundation Fieldbus?

Fieldbus is a digital serial, two-way communications system. Fieldbus is used in both process and manufacturing automation applications and has a built-in capability to distribute the control application across the network. The Foundation Fieldbus is owned by a non-profitable organization.

The Fieldbus serves as a Local Area Network (LAN) for factory /plant instrumentation and control devices.

Main features:

  • Foundation ™ Fieldbus offers interoperability; a Fieldbus® device can be replaced by a similar device with additional functionality from a different provider in the same Fieldbus® network while maintaining the specified operations

  • With Foundation ™ Fieldbus, multiple variables from each device can be incorporated into the plant’s control system to analyze trends, optimize processes and generate reports.

  • Fieldbus technology helps manufacturing plants meet the stringent safety requirements. It can provide operators with a prior warning of possible dangerous conditions.

  • The use of existing cabling and multipoint connections provides significant savings in the costs of installing the network.

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