We currently use a Modbus system through P+F barriers in order to pick up several 4-20ma loops. We want to change to Fieldbus in order to reduce cabling. All our instruments are Rosemount Fieldbus capable but we need some guidance on how we can use this in a hazardous area and how we can collect data using ISaGRAF software.

 

Hello there,

Have you tried looking into Emerson Rosemount 3420 Series: Fieldbus Interface Module. Basically it converts several field instrument Fieldbus input signal to a single MODBUS RTU (RS485) output for TX. So you can keep your exsiting MODBUS system.

However the 3420 is certified to EEx nA nL IIC which means it is suitable for use in Zone 2 only. Depending on your site's standards I believe it could be Exd for use in Zone 1. Have a chat with Emerson and see what they have to say. It might also be worth speaking to MTL.

I have no clue on ISaGRAF software!

 

Hello;

The best information on Fieldbus Foundation that I have found on the Web comes from Emerson's Plantweb University; search for it on the Net. They have a free modular tutorial that is complete, well-documented and very clear. It is worth spending one or 2 days to go through the material, especially if you want to make your conversion as fast and painless as needed.

About you Isagraph connection, I hope someone here can give you more information, this is somewhat out of my range.

Hope this helps,
Daniel Chartier