Friday, May 2, 2014

Could IEC 61850 be used for I/O applications as AS-i bus or Profibus DP?

Definitely one of the crucial objectives of IEC 61850 is to model, collect, and exchange Input and Output data! Many of the I/O technologies listed below (in a job description I just found today) are simply providing the exchange of bits and bytes over a communication link:

A well known company is looking (maybe) for you if you have – among other qualifications – “Experience with I/O technologies including FF, HART, WirelessHART, Profinet / Profibus DP, Ethernet IP / DeviceNet, Modbus / Modbus TCP, AS-i bus, IEC 61850, Wireless, Remote I/O technologies.”

IEC 61850 is much more than a I/O technology: BUT it is also a (very smat) I/O technology!! Sure it is! Why not?

So, is IEC 61850 competing with AS-i? No! I have written the first draft of the AS-i standard (IEC 62026-2) … some 20 years ago. It could provide the data we model and communicate to a higher level in an automation system. Data about a simple switch status or whatever. In the same way a Modbus device could provide I/O-data to an IEC 61850 server that provides input to a higher layer IEC 61850 or …

Yes, many signals are simply I/O data. IEC 61850 can handle them all …

What is the main difference between IEC 61850 and many of the field busses? Simply this: IEC 61850 applies an event-driven approach with DataSets and Controlblocks while most field busses run cyclic polling by a master device. The master polls for values … one field device after the other … again and again … IEC 61850 works like this:


IEC 61850 is usually (if used that way!) communicating useful information rather than bunches of Data – that just may tell the receiver: nothing has changed, nothing has changed, nothing has changed, … stop here and make it smarter. This could easily applied when Ethernet infrastructure is in place anyway.

This is one of the major paradigm shifts in process information exchange … that will take decades to understand by …

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