Thread Starter


I am looking at upgrading a control system which currently uses Interbus as it's main fieldbus interface. I have noted that the Interbus Club users group has closed and recommends upgrading to Profinet.

Other than this, I can find no other information on Interbus obsolescence status. Does anybody else have any other information on this? If this is obsolete then is the most obvious upgrade to Profinet?

bob peterson

A lot depends on what equipment is actually connected to the network and what part of the world you are in.

Interbus seems to have all but died, so it is probably a good idea to migrate to something that will be around a while.

It is possible there is some kind of adaptor doohickey you could purchase that would simplify the conversion, but most likely it will be moderately painful and expensive.

Your other option is to buy enough spares that you can keep the plant going until you either quit or retire.

Interbus was/is a perfectly acceptable low level fieldbus for discrete I/O. Competition over the years has made it less competitive than other buses such as ASi and DeviceNet. The only reason to change bus technologies is when you can no longer expand or maintain your current network as suppliers drop support or no longer make compatible devices.

PROFINET does not replace Interbus at the lowest levels, although it is an excellent technology for higher level aggregation of low level I/O. I usually recommend the use of ASi at the device level unless your plant uses Rockwell or Omron PLCs; then I recommend DeviceNet for the I/O devices. Connection of ASi to the PLC is easily made with either PROFIBUS or PROFINET.

My book, Automation Network Selection, covers these fieldbus choices. We all learn a lot by reading these messages; I was not aware the Interbus Club had closed.

Dick Caro
Richard H. Caro, CEO, CMC Associates
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

bob peterson

ASI is not well supported in the US, and does not handle analog well at all.

Devicenet is a PITA a lot of times if all you are worried about is I/O. It is better used as a device bus rather than for I/O. It handles analog better than ASI but not real well.

A lot depends on what you have there now. Sometimes it is relatively simple to go to something else, other times it is painful and expensive.

You should check with ODVA. Their website is ODVA is the organization that supports a variety of device level network protocols: DeviceNET, EthernetIP, CompoNet and ControlNet.

Alternatively, Profibus and ProfiNet are supported by the Profibus International organization, PI, whose website is


Walt Boyes, FInstMC, Chartered Measurement and Control Technologist
Life Fellow, International Society of Automation
Editor in Chief, Control and
wboyes [at] putman [dot] net