Hello people.

I had an interview a week or so ago and during the more general chat I have either misheard something or come across something that doesn't seem normal.

that being that a fella said he was in the process of swapping some signals from Fieldbus to 4-20ma.

have I simply heard wrong or is there a reason why someone might swap a working loop from Fieldbus to 4-20ma.
I'm no expert AT ALL but I thought Fieldbus was advantageous in every way.
The loop/signal in question was on a Delta-V ICSS system.

If anyone can give me any insight it would be greatly appreciated.

Kind Regards
Marty

 

I know of one plant in the midwest that tore out all its Foundation Fieldbus and went back to 4-20mA HART two years ago.

The reason is that in the 20 odd years since FF was installed, those initially trained on it have left or gone on to other jobs and attempts to hire FF-experienced and skilled personnel to keep the now 20 year old networks running was a huge burden. It takes a skilled guy interpret the data using one of those FF network analyzers.

FF never took off like it did in Asia because the US built so few greenfield plants whereas they were popping up like weeds in Asia.

I had a first time ever brush with FF a year ago and found there was very little support for FF from the US manufacturer. 95% of the Youtube videos are sales presentations. There's very little dealing with commissioning or troubleshooting FF networks. There was lots of manufacturer training when FF was new, but that's largely disappeared over time.

 

David_2 is so right ...

But Fieldbus and it's associated protocols such as Profibus is very much alive in Europe mainly due to Siemens.
Another view is the Nuclear Industry - always looking for the Kiss principle (keep it simple stupid), so Analogue signals appear far more reliable when it's one-per-cable than Networking several hundred together. Having a plethora of signals down a fibre cable can frighten a Nuclear Engineer all for the right reasons when he is looking at diverse cable routing and seismic protection.