I am currently on a research regarding wireless networks in the Process Automation Industry. and first of all I would like to know what are the differences between the ISA 100.11a standard and the IEEE 802.XY standards?

 

To the best of my knowledge, there is no IEEE 802.XY. X and Y are placeholders in the IEEE nomenclature schema.

ISA100.11a is an ANSI accredited standard that has just failed of acceptance by the IEC. There are three large vendors supporting this standard, but only one (Yokogawa) makes very large volumes of field instruments.

IEC62591 (also known as WirelessHART) has the most traction of any wireless standard currently, with thousands of units installed, and over a dozen vendors making devices for it.

There are virtually no operational differences (the way we will actually use them) between ISA100.11a and IEC62591, except that by ISA's design, they are mutually incompatible and non-interoperable. Vendor politics killed a convergence effort called ISA 100.12 earlier this year.

The reason both standards were developed is that there exists no IEEE standard that directly fits the use cases for process automation. Both ISA100.11a and IEC62591 are developments based on IEEE 802.15.4, as are the Chinese standard WIA-PA and the building automation and smart grid standard, Zigbee.

Walt Boyes, FInstMC, Chartered Measurement and Control Technologist
Life Fellow, International Society of Automation
Editor in Chief, Control and ControlGlobal.com
[email protected]

 

ISA100.11a is an approved ISA/ANSI standard built specifically for process automation and control, and is based on IEEE 802.15.4, a "personal area network" (PAN) standard that covers only the lowest 2 layers of the communications stack. ISA100.11a completes the communications stack by adding multipath and interference protection, duocast meshing, tool-free field configuration, peer-to-peer messaging, and internet addressability. It currently in the middle of IEC standardization as IEC 62734.

The IEEE series of 802 standards includes 802.3 (Ethernet) and 802.11 (Wi-Fi). All IEEE 802 standards define only the lowest 2 layers of the ISO Open System Interconnection communications stack. Typically, other consortiums specialize IEEE 802 protocols for specific application needs. There are a number of industrial application specific add-ons to IEEE 802.3 - Ethernet such as EtherNet/IP, PROFINET, Foundation Fieldbus HSE, EtherCAT, and Modbus TCP. There are currently no industrial application specific add-ons to IEEE 802.11.

Dick Caro
Certified Automation Professional (ISA)
Buy my books at the ISA Bookstore:
Wireless Networks for Industrial Automation
Automation Network Selection
Consumers Guide to Fieldbus Network Equipment for Process Control
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