foundation fieldbus or profibus from field devices?


Thread Starter


Availability of foundation fieldbus or profibus from field devices. Can someone help in regards this with respect to the PLC brands which supports this. If possible configuration details for such a system

Jeff Hunkele

Definately don't use Fieldbus. We just did a study on a project coming up with over 60 instruments on one reactor. We are planning on upgrading our system to DeltaV, but wanted to study the differences between fieldbus, ASiBus, and traditional I/O.

The total cost: DeltaV hardware, Installation, and instrumentation between the different options were within $7,000 of each other. Surprisingly, Fieldbus WAS NOT the cheapest, against everything published from Emerson (Fisher Rosemount). This was a detailed study. Plus there are questions as to whether any of the buses will stay around long enough although Fieldbus is definately the strongest.

Just please take a look at whether or not you are truly saving capital, plus the added expense of training maintenance on the new devices, spare parts, plus, try to find a contractor who has experience installing them.

Good luck.
I am interested in hearing a few more details about your project as I am now currently involved in an upgrade and our group is attempting to answer the Fieldbus question. The wiring benifets for us are a little more obvious, cutting over a purely pneumatic system. But where existing wiring is already run a more practical approach would see us leave the bus technology alone
utilize existing wiring and save money on the end devices by going with HART or simple 4-20.

On the other hand we have some reactors as well and field bus seems like a good alternative for that due to the type J thermo-couple home runs that would be costly to re-route. Utilizing Rosemounts multi-input temp transmitters we can
see 8 points on one transmitter and many points back on one H1 segment, a very cost effective alternative.

I guess it comes down to how effective is your host at handling several types of comm. FF, Profibus, Ausibus, Hart. As all of these protocols have thier own place in industry based on popularity and installed base, not weather they do the job the best.



Jeff Hunkele


I will be glad to when we are fully complete. I completed the study, with another engineer, but we have yet to present it. There may be
some questions/changes after that.

It sounds like we are in the same boat...although we don't have much pneumatic. Most of ours is manual operation. So all of our wiring will be new....and the installation cost of Fieldbus is MUCH less expensive (about half the cost!). However, our study found that going completely with FB instruments was not cost effective. We also looked at ASiBus and IS systems (due to Cl I, Div I) and mixtures of all of the above.

Again, I will be glad to share this info (once we share it with our bosses - w/ their approval). Please send me your email at [email protected]